Prognostic factors and treatment outcomes in patients with pleomorphic rhabdomyosarcoma: a population-based cohort study.

BACKGROUND: Pleomorphic rhabdomyosarcoma is a rare sarcoma in adults. The clinical characteristics, outcomes and prognostic factors associated with pleomorphic rhabdomyosarcoma remain unclear. METHODS: We retrospectively analyzed data from the Bone and Soft Tissue Tumor Registry of Japan, and enrolled patients with pleomorphic rhabdomyosarcoma. Disease-specific overall survival, local recurrence-free survival and distant metastasis-free survival were estimated using the Kaplan-Meier method; Cox regression model was used to identify prognostic factors. RESULTS: In total, 182 patients with pleomorphic rhabdomyosarcoma were included. Median age was 63 (range 20-95) years. The lower extremity (48%) was the most frequent tumor origin site, while head and neck were rare (4%). A total of 43 patients (24%) had distant or regional nodal metastases at first presentation. In all cases, the 2-year and 5-year survival rates were 66.3% and 54.1%, respectively. Distant metastasis was a significant poor prognostic factor (Hazard ratio 6.65; 95% confidence intervals, 3.00-14.75, P < 0.0001), with median survival of such patients being 9.4 (95% confidence intervals: 5.3-12.2) months. In 134 localized cases, the 2-year and 5-year survival rates were 91.5% and 68.3%, respectively. Large tumor size and older age were associated with poorer prognosis. Through data from localized and locally curative cases extracted and adjusted by propensity score matching, we found that perioperative chemotherapy did not improve disease-specific overall survival, distant metastasis-free survival or local recurrence-free survival. CONCLUSIONS: Clinical characteristics and outcomes of pleomorphic rhabdomyosarcoma are similar to those of other high-grade soft tissue sarcomas. Pleomorphic rhabdomyosarcoma may be less chemosensitive, and a strategy other than the standard cytotoxic chemotherapy is required to improve its prognosis.

Extended curettage for tumour-induced osteomalacia in the bone.

BACKGROUND: extended curettage is generally used to treat infiltrative bone tumours. However, the extent of the curettage performed in previous studies remains unclear. This study aimed to investigate the efficacy of extended curettage for bone tumour-induced osteomalacia. METHODS: we included 12 patients with tumour-induced osteomalacia who underwent extended curettage at our hospital between 2000 and 2022. Extended curettage was applied in cases where tumour resection could cause functional impairment or necessitate complex reconstruction. We investigated patients' clinical and oncological outcomes. RESULTS: patients had a mean age of 55 (24-81) years, and the median follow-up duration after surgery was 3.9 (1.0-14.0) years. The causative tumours were located in the pelvis and lumbar spine. Imaging revealed the tumours to be of the sclerotic, intertrabecular, lytic and mixed types. Intraoperative 3D fluoroscopy was used in 10 patients. Extended curettage with high-speed burring and adjuvant therapy with cauterization using an electric scalpel and ethanol resulted in a remission rate of 83%; no recurrence or metastasis was observed in cases of early postoperative biochemical remission. In cases where the causative tumour was at the lumbar spine and ischium close to the acetabulum, no postoperative biochemical remission was observed, and conservative treatment was continued. Except for one patient with a tumour in the lumbar spine, all patients could walk without a cane. CONCLUSIONS: extended curettage for bone tumour-induced osteomalacia is oncologically and functionally favourable, especially in cases where resection of the causative tumour could cause functional impairment or necessitate complex reconstruction.

Embryonal and alveolar rhabdomyosarcoma in adolescents/young adults, adults and older adults: a population-based cohort study.

BACKGROUND: The clinical characteristics, outcomes, and prognostic factors of adult embryonal rhabdomyosarcomas (ERMS) and alveolar rhabdomyosarcomas (ARMS), particularly the differences among adolescents/young adults (AYA), adults, and older adults, remain unclear. We assessed the clinicopathological features and survival outcomes of adult patients with ERMS and ARMS in Japan and to compare these features among AYA, adult, and older adult patients. METHODS: We retrospectively analyzed data from the Bone and Soft Tissue Tumor Registry of Japan and enrolled patients aged ≥15 years with ERMS and ARMS. Disease-specific overall survival (DOS) was estimated using the Kaplan-Meier method, and a Cox regression model was used to identify prognostic factors. RESULTS: Among 184 patients with ERMS and ARMS (median age, 27 years; interquartile range, 18-49 years), a high rate of distant and regional nodal metastases was initially observed in 65 (35%) and 66 (36%) cases, respectively. Older age and distant metastasis at first presentation were statistically poor prognostic factors, and histological subtype and site of tumor origin were not associated with DOS. In patients with localized ERMS and ARMS, older age and nodal metastasis were poor prognostic factors; the 5-year DOS rates of patients with and without nodal metastasis were 23% and 72%, respectively. CONCLUSIONS: Older patients with rhabdomyosarcoma had a dismal prognosis, and distant metastasis was a poor prognostic factor. The prognostic factors differed between adult and pediatric patients with rhabdomyosarcoma; biological analyses, such as genome analysis of adult rhabdomyosarcoma and clinical trials with pediatric oncologists, are needed to improve the prognosis of adult rhabdomyosarcoma.

BRAF mutations and concurrent alterations in patients with soft tissue sarcoma.

BRAF alterations, including V600E and non-V600E mutations and fusions, in soft tissue sarcoma (STS) have been identified in a limited case series. Here, we aimed to evaluate the frequency of BRAF mutations and concurrent alterations in STS to understand their therapeutic action. In this retrospective analysis, we included data from 1964 patients with advanced STS who underwent comprehensive genomic profiling tests at hospitals in Japan between June 2019 and March 2023. The prevalence of BRAF and recurrent concurrent gene alterations were also investigated. BRAF mutations were detected in 24 (1.2%) of 1964 STS patients, with a median age of 47 (range 1-69) years. BRAF V600E was detected in 11 (0.6%) of the 1964 patients with STS, BRAF non-V600E mutations in 9 (4.6%), and BRAF fusions were detected in 4 (0.2%). BRAF V600E was identified in 4 (0.2%) cases of malignant peripheral nerve sheath tumors. The most common concurrent alteration was CDKN2A (11 cases, 45.8%), and the frequency was equivalent to that of the BRAF V600E (5/11 cases, 45.5%) and non-V600E (5/9 cases, 55.6%) groups. Recurrent concurrent alterations, such as TERT promoter mutations (7 cases, 29.2%), were detected at the same frequency in the V600E and non-V600E groups. In contrast, TP53 alterations (4/9 cases, 44.4%) and mitogen-activated protein kinase (MAPK)-activating genes, including NF1, GNAQ, and GNA11 (3/9 cases, 33.3%), were identified as relatively higher in the non-V600E group than in the V600E group (each 1/11 case, 9.1%). We identified BRAF alterations at a rate of 1.2% in all patients with advanced STS. Among them, BRAF V600E and BRAF fusions account for 45.8% and 16.7%, respectively. Collectively, our findings support the clinical characteristics and therapeutic strategies for patients with BRAF-altered advanced STS.

Dramatic response to entrectinib in a patient with malignant peripheral nerve sheath tumor harboring novel SNRNP70-NTRK3 fusion gene.

Neurotropic tropomyosin receptor kinase (NTRK) gene rearrangements have been reported in limited cases of sarcomas; however, to date, there has been only one report of such rearrangements in malignant peripheral nerve sheath tumors (MPNSTs). Herein, we describe a 51-year-old male patient with a buttock tumor arising from the sciatic nerve, which was diagnosed as MPNST with positive S-100 staining, negative SOX10 staining, and loss of trimethylation at lysine 27 of histone H3 (H3K27me3) confirmed by immunohistochemistry. Soon after the resection of the primary tumor, the patient was found to have pulmonary and lymph node metastases. Chemotherapy with eribulin and trabectedin showed limited effects. However, the patient responded rapidly to pazopanib, but severe side effects caused discontinuation of the treatment. RNA panel testing revealed a novel fusion gene between Small Nuclear Ribonucleoprotein U1 Subunit 70 (SNRNP70) gene and NTRK3 gene. Furthermore, loss of NF1, SUZ12, and CDKN2A genes was confirmed by DNA panel testing, which is compatible with a histological diagnosis of MPNST. SNRNP70 possesses a coiled-coiled domain and seems to induce constitutive activation of NTRK3 through dimerization. In fact, immunohistochemistry revealed diffuse staining of pan-TRK within tumor cells. Treatment with entrectinib, which is an NTRK inhibitor, showed a quick and durable response for 10 months. Although NTRK rearrangements are very rare in MPNST, this case highlights the importance of genetic testing in MPNST, especially using an RNA panel for the detection of rare fusion genes.

Role of perioperative chemotherapy and radiotherapy for localized high-grade malignant peripheral nerve sheath tumor at the extremities and trunk wall: a population-based cohort study.

BACKGROUND: Primary tumor resection is the mainstay of treatment for malignant peripheral nerve sheath tumors. However, the efficacy of perioperative chemotherapy and radiotherapy for malignant peripheral nerve sheath tumors has not been elucidated. METHODS: This retrospective analysis based on a Japanese registry included patients with localized malignant peripheral nerve sheath tumors arising at the extremities and trunk wall. Disease-specific overall survival and local recurrence-free survival were estimated using the Kaplan-Meier method. A Cox regression model was used to identify prognostic factors. Characteristics of groups with or without chemotherapy were adjusted using propensity score matching. RESULTS: In total, 291 patients were included. The 5-year disease-specific overall survival rate was 70.6%. Multivariate analysis of disease-specific overall survival revealed that deep-seated tumors were a poor prognostic factor, but perioperative chemotherapy was not associated with disease-specific overall survival (hazard ratio, 0.81; 95% confidence interval, 0.45-1.43, P = 0.46). Local recurrence was observed in 55 patients (19.0%), and surgical margins (R1 and R2) were significant risk factors. Overall, perioperative chemotherapy did not prolong disease-specific overall survival (5-year disease-specific overall survival: 74.1% vs. 69.3%, P = 0.75) and had limited efficacy in the group with tumor size ≥ 5 cm, although the difference was not statistically significant (5-year disease-specific overall survival: 77.2% vs. 68.6%, respectively, P = 0.13). After adjustment by propensity score matching, perioperative chemotherapy significantly prolonged disease-specific overall survival (5-year disease-specific overall survival: 74.9% vs. 57.1%, P = 0.03), but this effect was not observed in local recurrence-free survival. In all patients, perioperative radiotherapy did not correlate with local recurrence-free survival (hazard ratio, 1.43; 95% confidence interval 0.78-2.62, P = 0.25). CONCLUSIONS: Perioperative chemotherapy had limited efficacy for disease-specific overall survival in patients with localized malignant peripheral nerve sheath tumors.

Clinical analysis of multimodal treatment for localized synovial sarcoma: A multicenter retrospective study.

INTRODUCTION: Several prognostic factors for survival in synovial sarcoma have been proposed, but the role of adjuvant chemotherapy and radiotherapy is a matter of debate. The study aim was to clarify the effect of high-dose ifosfamide-containing chemotherapy and adjuvant radiotherapy for patients with localized synovial sarcoma. MATERIALS AND METHODS: Five tertiary musculoskeletal oncology hospitals participated in this retrospective study. The records of the patient diagnosed with synovial sarcoma without metastasis at diagnosis from 1990 to 2011 have been collected and reviewed. Overall, distant failure-free, and local failure-free survivals were calculated, and prognostic factors for each survival were evaluated by performing univariate and multivariate analyses. RESULTS: A total of 162 patients were enrolled in this study with a median follow-up period of 67 months (range, 5-267 months) for all surviving patients. The 5-year overall, distant failure-free, and local failure-free survival rates were 79.7%, 66.3%, and 98.4%, respectively. Univariate analyses demonstrated that high-dose ifosfamide-containing chemotherapy was significantly associated with better overall (p = 0.014) and distant failure-free survival (p = 0.0043) than that of low-dose or no ifosfamide-containing chemotherapy if we analyzed only patients with tumors >5 cm in size. Addition of radiotherapy was not a significant prognostic factor for overall survival in the univariate and multivariate analyses, but it did improve the overall survival of the patients with R1 resection (p = 0.053). CONCLUSION: Patients with localized synovial sarcoma >5 cm in size had better overall and distant failure-free survival after receiving adjuvant chemotherapy containing high-dose ifosfamide comparing to low-dose or no ifosfamide-containing chemotherapy. The addition of adjuvant radiotherapy was beneficial for the patients who received R1 resection. Alternatively, adjuvant radiotherapy could be avoided for patients who achieved an R0 margin.

Clinical characteristics of undifferentiated pleomorphic sarcoma of bone and the impact of adjuvant chemotherapy on the affected patients: a population-based cohort study.

BACKGROUND: Clinical characteristics of undifferentiated pleomorphic sarcoma of bone are not elucidated. Herein, we clarify its clinical features and analyze the efficacy of adjuvant chemotherapy in patients with undifferentiated pleomorphic sarcoma of bone. METHODS: Prognostic factors and estimated disease-specific survival in 247 patients with primary undifferentiated pleomorphic sarcoma of bone were identified from a registry in Japan. The effect of adjuvant chemotherapy was evaluated in localized resectable cases, and the characteristics of the two groups treated with or without chemotherapy were adjusted using propensity score matching. RESULTS: The 5-year disease-specific survival rates were 47.4% in the entire cohort and 56.4 and 16.9% in the M0 and M1 groups, respectively. Multivariate disease-specific survival analysis revealed that metastasis on initial presentation and age ≥ 65 years were poor prognostic factors. Overall, 132 localized and resectable primary lesions were extracted. Adjuvant chemotherapy administration was a favorable prognostic factor (hazard ratio: 0.43, P = 0.04), and it significantly prolonged disease-specific survival compared with no adjuvant chemotherapy (5-year disease-specific survival: 78.8% vs. 51.8%, P = 0.008). Adjuvant chemotherapy prolonged disease-specific survival in patients with tumor size <8 cm (5-year disease-specific survival: 100% vs. 54.6%, P = 0.02); however, its efficacy decreased in those with tumor size ≥8 cm (5-year disease-specific survival: 68.7% vs. 42%, P = 0.09). After propensity score matching, adjuvant chemotherapy was significantly associated with good disease-specific survival (P = 0.02). CONCLUSIONS: Metastasis in the initial presentation was the poorest prognostic factor. On evaluating localized and resectable cases only, adjuvant chemotherapy significantly improved disease-specific survival, although its effect decreased in cases with large tumors.

Comparison of clinical features and outcomes of patients with leiomyosarcoma of bone and soft tissue: a population-based cohort study.

BACKGROUND: Leiomyosarcoma commonly occurs in soft tissue but rarely in the bone. Whether leiomyosarcoma of bone and soft tissue have similar clinical characteristics and outcomes remains unknown. METHODS: This retrospective analysis was based on data from the Bone and Soft Tissue Tumor Registry in Japan. Patients with leiomyosarcoma of bone and soft tissue were enrolled. Overall survival and distant metastasis-free survival were estimated using the Kaplan-Meier method, and the Cox regression model was used to identify the prognostic factors. RESULTS: A total of 888 patients (60 leiomyosarcoma of bone and 828 leiomyosarcoma of soft tissue) were included in the study. Clinical characteristics were similar between the two groups, except for younger age in leiomyosarcoma of bone than in leiomyosarcoma of soft tissue (median 56 years vs. 66 years, P < 0.0001). To evaluate the prognostic factors and efficacy of adjuvant chemotherapy, data of localized and locally curative cases were extracted (total 572: 33 leiomyosarcoma of bone and 539 leiomyosarcoma of soft tissue). The 5-year overall survival rates of leiomyosarcoma of bone and soft tissue patients were similar (63.8% vs. 75.2%, P = 0.43); the 5-year distant metastasis-free survival tended to be worse in leiomyosarcoma of bone than in leiomyosarcoma of soft tissue (37.4% vs. 57.9%, P = 0.28). Larger tumor size (≥5 cm) and older age (≥65 years) correlated with poor overall survival in leiomyosarcoma of soft tissue patients. Adjuvant chemotherapy tended to prolong the overall survival of both leiomyosarcoma of bone (P = 0.11) and leiomyosarcoma of soft tissue patients with tumor size >10 cm (P = 0.06). CONCLUSIONS: The clinical characteristics and outcomes of leiomyosarcoma of bone and soft tissue patients were similar. In localized cases, adjuvant chemotherapy may improve the survival of leiomyosarcoma of bone and soft tissue patients with large-size tumor.

Preoperative arterial embolization and wound complications after resection of malignant bone tumor in the pelvis: a nationwide database study.

BACKGROUND: Massive intraoperative blood loss is common in pelvic malignant bone tumor surgery, and preoperative arterial embolization may be used in selected cases. Preoperative arterial embolization reportedly increases wound complications in pelvic fracture surgery, but little evidence is available regarding pelvic bone tumor surgery. METHODS: Using a Japanese nationwide database (Diagnosis Procedure Combination database), we searched for patients who underwent pelvic malignant bone tumor surgery between July 2010 and March 2018. The primary endpoint was wound complications, defined as any wound requiring re-operation, negative pressure wound therapy or both. Univariate analyses (the chi-squared test for categorical variables, the unpaired t-test for continuous variables) and multivariate logistic regression analyses were performed to examine the association between preoperative arterial embolization and wound complications. RESULTS: Among the 266 eligible patients, 43 (16%, 43/266) underwent embolization and 69 (26%, 69/266) developed wound complications. In the univariate analyses, preoperative arterial embolization (P < 0.001), duration of anesthesia (P < 0.001), the volume of blood transfusion (P < 0.001) and duration of indwelling drain tube (P < 0.001) were associated with wound complications. In the multivariate logistic regression analysis, preoperative arterial embolization was significantly associated with wound complications (odds ratio, 3.92; 95% confidence interval, 1.80-8.56; P = 0.001). CONCLUSIONS: Preoperative arterial embolization may be associated with increased wound complications after pelvic malignant tumor surgery.

Role of adjuvant chemotherapy in patients with localized, undifferentiated pleomorphic sarcoma of soft tissue: a population-based cohort study.

BACKGROUND: Primary tumor resection is the mainstay of treatment for undifferentiated pleomorphic sarcoma (UPS); however, the necessity of adjuvant chemotherapy has been debated. We aimed to clarify the effect of adjuvant chemotherapy on survival rates in patients with UPS with localized and resectable primary lesions. METHODS: This retrospective analysis included data of 2112 patients with localized UPS arising in the extremities and trunk, extracted from a registry in Japan. We estimated overall survival (OS), identified prognostic factors, and adjusted patient characteristics in the two groups treated with or without chemotherapy using propensity score matching (PSM). RESULTS: The 5-year OS rate was 79.4%. In multivariate OS analysis, adjuvant chemotherapy was a good prognostic factor (hazard ratio 0.65; 95% confidence interval 0.48-0.9, P = 0.009). Large tumor size was the poorest prognostic factor, and OS decreased with the tumor size (P < 0.0001). In all patients, adjuvant chemotherapy prolonged OS (5-year OS: 82.3% vs. 78.6%, P = 0.03). Adjuvant chemotherapy did not affect OS in patients with tumor size < 5 cm; the benefit was strong in patients with tumor size 10 to < 15 cm (5-year OS: 79.5% vs. 66.8%, P = 0.003). Adjuvant chemotherapy efficacy was not pronounced in patients with tumor size 5 to < 10 cm (5-year OS: 87% vs. 80%, P = 0.06) and ≥ 15 cm (5-year OS: 60.7% vs. 49.5%, P = 0.08). After PSM, adjuvant chemotherapy was significantly associated with improved OS (P = 0.02). CONCLUSIONS: In patients with localized UPS, adjuvant chemotherapy tended to improve OS when tumors were ≥ 5 cm, especially when they were 10 to < 15 cm.

Epithelioid hemangioma of bone harboring FOS and FOSB gene rearrangements: A clinicopathologic and molecular study.

The diagnosis of epithelioid hemangioma (EH) remains challenging due to its rarity, worrisome histologic features, and locally aggressive clinical and radiographic presentation. Especially in the bone, EH can be misdiagnosed as a malignant vascular neoplasm due its lytic, often destructive or multifocal growth, as well as atypical morphology. The discovery of recurrent FOS and FOSB gene fusions in the pathogenesis of most EH has strengthened its stand-alone classification, distinct from other malignant epithelioid vascular lesions, such as epithelioid hemangioendothelioma or angiosarcoma. In this study we investigate a group of molecularly confirmed skeletal EH by the presence of FOS or FOSB gene rearrangements to better define its clinical and pathologic characteristics within a homogenous molecular subset. The cohort included 38 patients (25 males, 13 females), with a mean age at diagnosis of 38 years (range, 4-75). Regional, multifocal presentation was noted in 10 cases. Only six cases were correctly recognized as EH by the referring institutions, while most were misdiagnosed as other vascular tumors. Of the 17 patients with follow-up data available, five patients (29%) developed local recurrence after marginal en bloc excision (n = 3) or curettage (n = 2). Local recurrence-free survival rates were 84% at 3 years and 38% at 5 years. No metastasis or disease-related death was identified. Imaging studies exhibited no specific features, showing cortical bone destruction and soft-tissue extension in 14 (38%) cases. FOS gene rearrangements were detected in 28 (74%) of cases, while FOSB rearrangements in 10 (26%) cases. Our results highlight the significant challenges encountered in establishing a correct diagnosis exclusive of the molecular testing, mainly due to its overlap to other malignant epithelioid vascular tumors. Skeletal EH emerges as a genetically defined locally aggressive vascular neoplasm, with a high rate of local recurrence, but lacking the propensity for distant spread.

Surgical outcomes of bone sarcoma of the foot.

OBJECTIVE: Limb-salvage following resection of bone sarcomas of the foot are challenging due to the complicated anatomy, adjacent neurovascular structures and few durable reconstruction options. METHODS: We retrospectively analysed 50 patients with primary malignant bone sarcoma of the foot who underwent surgery including chondrosarcoma (n = 23), Ewing's sarcoma (n = 14) and osteosarcoma (n = 13). RESULTS: Median follow-up was 68 months. The primary sites were metatarsal (n = 18), phalanges (n = 15), calcaneus (n = 13) and others (n = 4). The 5-year disease-specific survivals were 100, 83 and 83% in chondrosarcoma, Ewing's sarcoma and osteosarcoma, respectively. Below knee amputation, ray/toe amputation, excision and curettage were performed in 21, 24, 2 and 3 patients, respectively. Below knee amputation was performed in 94% of mid/hindfoot tumours. Surgical margins were wide/radical, marginal and intralesional margin in 42, 5 and 3 patients. Three patients (6%) developed local recurrence, whereas, local recurrence was not observed in patients with wide/radical margins. Postoperative complications occurred in 3 patients (6%; surgical site infection n = 2 and delayed wound healing n = 1). Mean MSTS functional score was 26 points (range, 19-30). CONCLUSIONS: Good local control was achieved with acceptable functional outcomes and post-operative complications; almost all mid/hindfoot tumours required below knee amputation achieving wide/radical margins without local recurrence.

Prognostic factors and impact of surgery in patients with metastatic soft tissue sarcoma at diagnosis: A population-based cohort study.

BACKGROUND: Approximately 10% of the patients with soft tissue sarcoma show metastasis at initial diagnosis, and hence, poorer prognosis. However, the prognostic factors and whether definitive surgery for the primary lesion improves overall survival, especially when complete resection of metastasis is difficult, remain unclear. METHODS: This retrospective analysis was based on the Bone and Soft Tissue Tumor Registry in Japan. Patients with soft tissue sarcoma having metastasis at diagnosis were enrolled, excluding those with Ewing's sarcoma, rhabdomyosarcoma and several other sarcomas with unique behavior and treatment strategies. Overall survival was estimated using the Kaplan-Meier method and compared among the common histologic subtypes. Multivariate analysis with the Cox regression model was used to identify the prognostic factors. RESULTS: In total, 1184 patients were included, with a median follow-up duration of 10 months (range: 1-83). The median overall survival was 21 months (95% confidence interval: 18.2-23.8). The multivariate analyses indicated that tumor size, grade and histologic subtypes significantly correlated with overall survival. Moreover, surgery for the primary lesion, in addition to surgery for metastases and chemotherapy, showed significant association with better survival. CONCLUSIONS: The prognostic factors in patients with metastatic soft tissue sarcoma at diagnosis are generally similar to those in patients with localized disease. The overall survival in patients differed significantly according to histologic subtype. Surgical resection of primary lesions, especially those with a wide margin, may be an independent prognostic factor. Further studies are needed identify which subgroup of patients would benefit the most from primary lesion surgery.

Pelvic reconstruction using an ice-cream cone prosthesis: correlation between the inserted length of the coned stem and surgical outcome.

BACKGROUND: Acetabular reconstruction using an ice-cream cone prosthesis has been a reliable reconstruction option following pelvic tumour resection. However, it remains unknown which factor determines the success of this procedure. We aimed to determine risk factors for complications and functional loss in acetabular reconstruction using an ice-cream cone prosthesis. PATIENTS AND METHODS: Fifty-four patients with malignant bone tumours who underwent acetabular reconstruction using an ice-cream cone prosthesis between 2004 and 2016 were studied. The bone-stem ratio was calculated as the ratio of the inserted length into the bone per the entire stem length. RESULTS: A total of 26 (48%) patients had at least one complication and 11 patients (20%) required surgical interventions. The complication rates were 71% and 40% with a bone-stem ratio ≤ 50% and > 50%, respectively (p = 0.026), and the bone-stem ratio significantly stratified the risk of complications (≤ 50%: OR, 4.67 versus > 50%; p = 0.048). The mean MSTS score at the final follow-up was 60% (range 23-97%): the scores were significantly lower in patients with complications/leg-length discrepancy (52%) than in those without (79%; p = 0.002). The mean score with a bone-stem ratio ≤ 50% was significantly lower than the score with a ratio > 50%, especially in patients who underwent non-navigated reconstructions (33% versus 64%; p = 0.001). CONCLUSION: The inserted length of the coned stem into residual bone was predictive of complications and functional outcome. Surgical indication for this procedure should be considered with the size of the remaining ilium to stabilise the prosthesis with a coned stem longer than half length.

How Are Indeterminate Pulmonary Nodules at Diagnosis Associated with Survival in Patients with High-Grade Osteosarcoma?

BACKGROUND: Pulmonary metastases are a poor prognostic factor in patients with osteosarcoma; however, the clinical significance of subcentimeter lung nodules and whether they represent a tumor is not fully known. Because the clinician is faced with decisions regarding biopsy, resection, or observation of lung nodules and the potential impact they have on decisions about resection of the primary tumor, this remains an area of uncertainty in patient treatment. Surgical management of the primary tumor is tailored to prognosis, and it is unclear how aggressively patients with indeterminate pulmonary nodules (IPNs), defined as nodules smaller than 1 cm at presentation, should be treated. There is a clear need to better understand the clinical importance of these nodules. QUESTIONS/PURPOSES: (1) What percentage of patients with high-grade osteosarcoma and spindle cell sarcoma of bone have IPNs at diagnosis? (2) Are IPNs at diagnosis associated with worse metastasis-free and overall survival? (3) Are there any clinical or radiologic factors associated with worse overall survival in patients with IPN? METHODS: Between 2008 and 2016, 484 patients with a first presentation of osteosarcoma or spindle cell sarcoma of bone were retrospectively identified from an institutional database. Patients with the following were excluded: treatment at another institution (6%, 27 of 484), death related to complications of neoadjuvant chemotherapy (1%, 3 of 484), Grade 1 or 2 on final pathology (4%, 21 of 484) and lack of staging chest CT available for review (0.4%, 2 of 484). All patients with abnormalities on their staging chest CT underwent imaging re-review by a senior radiology consultant and were divided into three groups for comparison: no metastases (70%, 302 of 431), IPN (16%, 68 of 431), and metastases (14%, 61 of 431) at the time of diagnosis. A random subset of CT scans was reviewed by a senior radiology registrar and there was very good agreement between the two reviewers (κ = 0.88). Demographic and oncologic variables as well as treatment details and clinical course were gleaned from a longitudinally maintained institutional database. The three groups did not differ with regard to age, gender, subtype, presence of pathological fracture, tumor site, or chemotherapy-induced necrosis. They differed according to local control strategy and tumor size, with a larger proportion of patients in the metastases group presenting with larger tumor size and undergoing nonoperative treatment. There was no differential loss to follow-up among the three groups. Two percent (6 of 302) of patients with no metastases, no patients with IPN, and 2% (1 of 61) of patients with metastases were lost to follow-up at 1 year postdiagnosis but were not known to have died. Individual treatment decisions were determined as part of a multidisciplinary conference, but in general, patients without obvious metastases received (neo)adjuvant chemotherapy and surgical resection for local control. Patients in the no metastases and IPN groups did not differ in local control strategy. For patients in the IPN group, staging CT images were inspected for IPN characteristics including number, distribution, size, location, presence of mineralization, and shape. Subsequent chest CT images were examined by the same radiologist to reevaluate known nodules for interval change in size and to identify the presence of new nodules. A random subset of chest CT scans were re-reviewed by a senior radiology resident (κ = 0.62). The association of demographic and oncologic variables with metastasis-free and overall survival was first explored using the Kaplan-Meier method (log-rank test) in univariable analyses. All variables that were statistically significant (p < 0.05) in univariable analyses were entered into Cox regression multivariable analyses. RESULTS: Following re-review of staging chest CTs, IPNs were found in 16% (68 of 431) of patients, while an additional 14% (61 of 431) of patients had lung metastases (parenchymal nodules 10 mm or larger). After controlling for potential confounding variables like local control strategy, tumor size, and chemotherapy-induced necrosis, we found that the presence of an IPN was associated with worse overall survival and a higher incidence of metastases (hazard ratio 1.9 [95% CI 1.3 to 2.8]; p = 0.001 and HR 3.6 [95% CI 2.5 to 5.2]; p < 0.001, respectively). Two-year overall survival for patients with no metastases, IPN, or metastases was 83% [95% CI 78 to 87], 65% [95% CI 52 to 75] and 45% [95% CI 32 to 57], respectively (p = 0.001). In 74% (50 of 68) of patients with IPNs, it became apparent that they were true metastatic lesions at a median of 5.3 months. Eighty-six percent (43 of 50) of these patients had disease progression by 2 years after diagnosis. In multivariable analysis, local control strategy and tumor subtype correlated with overall survival for patients with IPNs. Patients who were treated nonoperatively and who had a secondary sarcoma had worse outcomes (HR 3.6 [95% CI 1.5 to 8.3]; p = 0.003 and HR 3.4 [95% CI 1.1 to 10.0]; p = 0.03). The presence of nodule mineralization was associated with improved overall survival in the univariable analysis (87% [95% CI 39 to 98] versus 57% [95% CI 43 to 69]; p = 0.008), however, because we could not control for other factors in a multivariable analysis, the relationship between mineralization and survival could not be determined. We were unable to detect an association between any other nodule radiologic features and survival. CONCLUSION: The findings show that the presence of IPNs at diagnosis is associated with poorer survival of affected patients compared with those with normal staging chest CTs. IPNs noted at presentation in patients with high-grade osteosarcoma and spindle cell sarcoma of bone should be discussed with the patient and be considered when making treatment decisions. Further work is required to elucidate how the nodules should be managed. LEVEL OF EVIDENCE: Level III, prognostic study.

Predictive factors of the 30-day mortality after surgery for spinal metastasis: Analysis of a nationwide database.

BACKGROUND: Surgical procedure for symptomatic spinal metastasis is expected to improve the quality of life. Factors related to short-term perioperative mortality after surgery for spinal metastasis may be different from those related to long-term mortality, which have classically been used to determine the indication for surgery. The purposes of this study were to evaluate factors related to the 30-day mortality after surgery for spinal metastasis and create an integer risk scoring system. METHODS: Using the Diagnosis Procedure Combination database from 2010 to 2016, we extracted data of patients who underwent surgical procedure for spinal metastasis. Multivariable logistic regression analysis was performed to clarify the association between patient backgrounds and the 30-day postoperative mortality. We created a risk scoring system using regression coefficients to estimate the 30-day mortality for each patient. RESULTS: Among 3524 patients, the 30-day mortality was 2.6%. Factors associated with a higher 30-day mortality were male sex (odds ratio, 2.50 [95% confidence interval, 1.45-4.31]), emergency admission (1.80 [1.11-2.92]), rapid growth tumors (3.83 [2.49-5.90]), and non-skeletal metastasis (2.27 [1.42-3.64]). In patients with the maximum risk score of five, the 30-day mortality was 16.2%. CONCLUSIONS: Factors related to the 30-day mortality were male sex, emergency admission, rapid growth tumors, and non-skeletal metastasis. These findings provide spine surgeons and patients knowledge of the potential risk of short-term perioperative mortality and allow them to consider the risk of surgery.

The clinical heterogeneity of round cell sarcomas with EWSR1/FUS gene fusions: Impact of gene fusion type on clinical features and outcome.

The genetic hallmark of classic Ewing sarcoma is a recurrent fusion between EWSR1 and FUS gene with a member of the ETS transcription factor family. In contrast, tumors with non-ETS gene partners have been designated until recently "Ewing-like sarcoma," as a provisional molecular entity, as their clinical and pathologic features were still evolving. However, this group was reclassified as "round cell sarcoma with EWSR1-non-ETS fusions" in the latest 2020 WHO classification. Moreover, round cell sarcomas with either CIC or BCOR gene abnormalities, initially classified under Ewing family of tumors, are now regarded as stand-alone pathologic entities based on their distinct features. In this study we investigated the clinical characteristics of 226 confirmed Ewing sarcoma patients (EWSR1-FLI1 [n = 176], EWSR1/FUS-ERG [n = 35], EWSR1/FUS-FEV [n = 12], and EWSR1-ETV1/4 [n = 3]) and 14 round cell sarcoma patients with EWSR1-non-ETS fusion (EWSR1/FUS-NFATC2 [n = 10], EWSR1-PATZ1 [n = 3], and EWSR1-VEZF1 [n = 1]). The impact on overall survival (OS) was assessed in 90 patients with available follow-up, treated between 2011 and 2018. Patients with fusions involving FEV and NFATC2 genes showed an older median age at diagnosis, compared to those with EWSR1-FLI1 (P = .005), while extraskeletal location was more common in tumors with noncanonical EWSR1-FLI1 fusions (P = .001). Axial and pelvic primary sites were more common in patients with EWSR1-FLI1 (72%), while tumors with NFATC2 fusions were more frequent in the limb (78%, P = .006). The 3-year OS in patients with EWSR1-FLI1 was 91%, compared to only 60% in patients with alternative fusions (P = .037); the latter group showing a higher rate of metastases at presentation. However, this OS difference was not significant in patients with localized tumor (P = .585). Our study demonstrates significant correlations between fusion subtype and age at presentation, primary tumor sites, and OS, in both conventional Ewing sarcoma and round cell sarcoma with EWSR1-non ETS fusions patients. Larger studies are needed to determine survival differences in localized tumors.

Ewing sarcoma with FEV gene rearrangements is a rare subset with predilection for extraskeletal locations and aggressive behavior.

The molecular hallmark of Ewing sarcoma (ES) is a fusion involving the EWSR1 gene and a member of the ETS family of transcription factors. EWSR1-FLI1 is the most common variant, occurring in 90% of cases, followed by EWSR1-ERG. In a small subset, the FUS gene can substitute for EWSR1 in these fusions. Only rare case reports have been described to date of ES with FEV gene rearrangements. In this study, we investigate the clinicopathologic and molecular features of 10 ES patients with FEV-rearrangements, either fused to EWSR1 (n = 4) or to FUS (n = 6). The median age at diagnosis was 38 years (range, 5-61 years); occurring in six males and four females. All tumors were located at extraskeletal sites, occurring more often in the axial soft tissues. Tumors had a similar morphologic appearance and immunophenotype as ES with more common EWSR1-ETS fusions. Of six patients with follow-up data, five patients (83%) developed metastasis and two patients (33%) died of their diseases. The diagnosis was confirmed either by fluorescence in situ hybridization and/or targeted RNA sequencing. In the five cases tested by targeted sequencing, the fusion transcripts were composed of EWSR1 or FUS fused to either exon 1 or 2 of FEV, retaining the FEV ETS DNA binding domain. This is the largest study to date investigating the ES subset with EWSR1/FUS-FEV fusions showing a predilection for extraskeletal sites and aggressive behavior.

Clinical and molecular characterization of primary sclerosing epithelioid fibrosarcoma of bone and review of the literature.

Sclerosing epithelioid fibrosarcoma (SEF) is a rare sarcoma subtype characterized by monomorphic epithelioid cells embedded in a densely sclerotic collagenous matrix. The overwhelming majority of tumors arise in soft tissues; however, rare cases have been documented to occur primarily in bone. The hallmarks of soft tissue SEF include MUC4 immunoreactivity and the presence of an EWSR1-CREB3L1 fusion. Rare cases with alternative fusions have also been reported such as EWSR1-CREB3L2 and FUS-CREB3L2 transcripts. The molecular alterations of skeletal SEF have not been well-defined, with only rare cases analyzed to date. In this study we investigated the clinicopathologic and molecular features of seven patients presenting with primary osseous SEF. There were 3 males and 4 females, with a mean age at diagnosis of 38 years. All cases had microscopic features within the histologic spectrum of SEF and showed strong and diffuse MUC4 positivity, while lacking SATB2 expression. However, due to its unusual presentation within bone, four cases were initially misinterpreted as either osteosarcoma, Ewing sarcoma or chondroblastoma. Half of the patients with follow-up data developed metastasis. The cases were tested by targeted RNA sequencing, MSK-IMPACT, and/or fluorescence in situ hybridization, showing EWSR1-CREB3L1 in six cases and EWSR1-CREB3L2 in one case. The fusion transcripts were composed of EWSR1 exon 11 to either exon 6 of CREB3L1 or CREB3L2. In summary, due to their rarity in the bone, skeletal SEF are often misdiagnosed, resulting in inadequate treatment modalities. Similar to their soft tissue counterpart, bone SEF follow an aggressive clinical behavior and show similar EWSR1-CREB3L1/CREB3L2 fusions.