Histological diagnostic discrepancy and its clinical impact in bone and soft tissue tumors referred to a sarcoma center.

Histological diagnosis of sarcomas (malignant bone and soft tissue tumors) is challenging due to their rarity, morphological diversity, and constantly evolving diagnostic criteria. In this study, we aimed to assess the concordance in histological diagnosis of bone and soft tissue tumors between referring hospitals and a tertiary sarcoma center and analyzed the clinical impact of the diagnostic alteration. We analyzed 628 consecutively accessioned specimens from 624 patients who visited a specialized sarcoma center for treatment. The diagnoses at referring hospitals and those at the sarcoma center were compared and classified into four categories: agreed, disagreed, specified, and de-specified. Of the 628 specimens, the diagnoses agreed in 403 (64.2%) specimens, whereas some changes were made in 225 (35.8%) specimens: disagreed in 153 (24.3%), specified in 52 (8.3%), and de-specified in 20 (3.2%) cases. The benign/intermediate/malignant judgment changed for 92 cases (14.6%). The diagnostic change resulted in patient management modification in 91 cases (14.5%), including surgical and medical treatment changes. The main inferred reason for the diagnostic discrepancies was a different interpretation of morphological findings of the tumor, which accounted for 48.9% of the cases. This was followed by the unavailability of specialized immunohistochemical antibodies and the unavailability of genetic analysis. In summary, our study clarified the actual clinical impact of diagnostic discrepancy in bone and soft tissue tumors. This may underscore the value of pathology consultation, facilitating access to specialized diagnostic tools, and continued education. These measures are expected to improve diagnostic precision and ultimately benefit patients.

Efficacy and safety of nivolumab monotherapy in patients with unresectable clear cell sarcoma and alveolar soft part sarcoma (OSCAR Trial/NCCH1510).

BACKGROUND: Clear cell sarcoma (CCS) and alveolar soft part sarcoma (ASPS) are rare, and standard systemic therapy is not established except for sunitinib in ASPS. It is known that CCS and ASPS have a common biological feature of melanoma and Xp11.2/TFE3 translocation renal cell carcinoma, and immune-checkpoint inhibitors (ICIs) are effective in these tumors. The authors conducted a phase 2 trial to evaluate the efficacy and safety of nivolumab for CCS and ASPS. METHODS: The number of patients expected to be enrolled was 15-25 and was determined based on the Bayesian design. The primary end point was the confirmed objective response rate (ORR) according to the central review and the secondary end points included ORR, progression-free survival (PFS), overall survival (OS), and safety. RESULTS: A total of 26 patients (CCS, 12; ASPS, 14) were enrolled. Efficacy and safety were analyzed on 25 and 26 patients, respectively. The minimum number of responses required for a positive conclusion regarding the efficacy was four. However, only one patient (4.0%) with ASPS had a partial response. Complete response, stable disease, progression disease, and not evaluable were 0%, 60%, 32%, and 4.0%, respectively. Adverse events of grade 3 or 4 occurred in 57.7% (15 of 26). The median PFS was 4.9 months (95% confidence interval [CI], 3.7-8.6 months) and the median OS was 15.8 months (95% CI, 8.2-not reached). CONCLUSIONS: The primary end point of the ORR was not met for CCS and ASPS on the central review. Further studies are needed to evaluate ICIs in patients with ASPS.

Inflammatory Rhabdomyoblastic Tumor: Clinicopathologic and Molecular Analysis of 13 Cases.

Inflammatory rhabdomyoblastic tumors (IRMTs) are newly recognized skeletal muscle tumors with uncertain malignant potential. We investigated 13 IRMTs using clinicopathologic, genetic, and epigenetic methods. The cohort included 7 men and 6 women, aged 23 to 80 years (median, 50 years), of whom 2 had neurofibromatosis type 1. Most tumors occurred in the deep soft tissues of the lower limbs, head/neck, trunk wall, and retroperitoneum/pelvis. Two tumors involved the hypopharyngeal submucosa as polypoid masses. Eight tumors showed conventional histology of predominantly spindled cells with nuclear atypia, low mitotic activity, and massive inflammatory infiltrates. Three tumors showed atypical histology, including uniform epithelioid or plump cells and mitotically active histiocytes. The remaining 2 tumors demonstrated malignant progression to rhabdomyosarcoma; one had additional IRMT histology and the other was a pure sarcoma. All 11 IRMTs without malignant progression exhibited indolent behavior at a median follow-up of 43 months. One of the 2 patients with IRMTs with malignant progression died of lung metastases. All IRMTs were positive for desmin and PAX7, whereas myogenin and MyoD1 were expressed in a subset of cases. Targeted next-generation sequencing identified pathogenic mutations in NF1 (5/8) and TP53 (4/8). All TP53 mutations co-occurred with NF1 mutations. TP53 variant allele frequency was much lower than that of NF1 in 2 cases. These tumors showed geographic (subclonal) strong p53 immunoreactivity, suggesting the secondary emergence of a TP53-mutant clone. DNA methylation-based copy number analysis conducted in 11 tumors revealed characteristic flat patterns with relative gains, including chromosomes 5, 18, 20, 21, and/or 22 in most cases. Widespread loss of heterozygosity with retained biparental copies of these chromosomes was confirmed in 4 tumors analyzed via allele-specific profiling. Based on unsupervised DNA methylation analysis, none of the 11 tumors tested clustered with existing reference entities but formed a coherent group, although its specificity warrants further study.

Impact of pump-phase noise in PPLN-based optical parametric amplifier and wavelength converter for digital coherent transmission.

Wideband signal amplification and optical signal processing with a high gain using an optical parametric amplifier based on a periodically poled LiNbO3 (PPLN) waveguide is attractive for constructing wideband optical fiber networks. We experimentally investigate the transfer characteristics of the phase noise of a pump laser in χ(2)-based optical parametric amplification and wavelength conversion on the basis of second-harmonic-generation and differential-frequency-generation processes. We also evaluate the effect of the transferred phase noise on signal quality in dispersion-unmanaged digital coherent fiber transmission systems. We show that the phase noise is transferred only to the wavelength-converted idler and does not affect the amplified signal even by using a pump laser with a MHz-order linewidth. We also show that the phase noise transferred to the idler light can have a similar impact on signal quality as equalization-enhanced phase noise (EEPN) in digital coherent transmission. The signal penalty including EEPN was evaluated with several pump lasers and at symbol rates of 32, 64, and 96 Gbaud. We also propose a method of using correlated pump lights between a wavelength converter pair to cancel out the transfer of phase noise.

Compressive time-stretch spectroscopy with pulse-by-pulse intensity modulation.

The photonic time-stretch technique is a single-pulse broadband spectroscopy method enabled by dispersive Fourier transformation. This technique enables an extremely high spectrum acquisition rate, determined by the repetition rates of femtosecond mode-locked lasers, which are typically in the range of tens of MHz. However, achieving this high spectrum acquisition rate necessitates a compromise in either the spectral resolution or the spectral bandwidth to prevent overlaps between adjacent stretched pulses. In this study, we introduce a method that overcomes this limitation by incorporating compressive sensing with pulse-by-pulse amplitude modulation, enabling the decomposition of excessively stretched, overlapping pulses. Through numerical evaluations of optofluidic microparticle flow analysis and high-speed gas-phase molecular spectroscopy, we demonstrate the efficacy of our noise-resilient algorithm, showcasing a severalfold increase in the spectrum acquisition rate without compromising resolution and bandwidth.

Clinical outcomes in patients with adamantinoma: Report from the bone and soft tissue tumor registry in Japan.

BACKGROUND: Adamantinomas are rare malignant bone tumors. Due to their low incidence, there are few reports on the clinical results of adamantinoma. OBJECTIVES: This study aims to clarify outcomes in patients with adamantinoma using data from the National Bone and Soft Tissue Tumor Registry. METHODS: From 2006 to 2019, 38 cases of tibial origin were included. Twenty-four were male and 14 were female, with a mean age of 37 (6-87) years and a mean follow-up of 35 (1-128) months. RESULTS: Surgery was performed in 33 cases (87%) (curettage: 4 cases, wide resection: 27 cases, amputation: 2 cases). Reconstruction was performed in 27 patients who underwent wide resection. A total of 12 additional surgeries were performed in 11 patients. The main reason for the additional surgeries was nonunion of grafting bone in 6 cases. Oncologic outcomes were DOC (death from other causes) in one case and NED (no evidence of disease) in 37 cases. CONCLUSIONS: The results of treatment of adamantinomas in Japan have been extremely favorable. This may be due in part to the large number of cases with wide resection.

Statistics of Visceral Sarcoma in Japan: Report From the Population-Based National Cancer Registry (NCR) in Japan.

BACKGROUND AND OBJECTIVES: Sarcomas developing in the visceral organs are extremely rare, with no previous reports to describe their national epidemiology. We analyzed Japanese domestic statistics for visceral sarcoma, using the National Cancer Registry (NCR) in Japan, a population-based database launched in 2016. METHODS: We identified 3245 cases of visceral sarcomas in the NCR dated 2016-2019 to analyze demographic and disease information, initial diagnostic process, volume and type of the hospitals, treatment, and prognosis. RESULTS: Visceral sarcoma shows a higher prevalence in the older generation (60+ years), with a significant male predominance (p = 0.006). Leiomyosarcomas occurred frequently in the gastrointestinal tract (N = 240; 39.5%), and angiosarcomas in the liver, gall bladder, pancreas, and spleen (N = 244; 43.9%). Visceral sarcomas were often treated in facilities of lower volume without specific adjuvant treatments (p < 0.001). The cumulative 3-year overall survival was 44.8%, and several factors such as surgery or absence of chemotherapy positively affected survival. CONCLUSIONS: This is the first nationwide study in Japan to analyze the inclusive epidemiology of visceral sarcomas. Visceral sarcomas are characterized by senior and male predominance with relatively poor prognosis, often managed in nonspecialized facilities and rarely with adjuvant therapies. Several histologic subtypes had the propensity to develop in specific organs.

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.

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.

Soft-tissue sarcoma in Japan: National Cancer Registry-based analysis from 2016 to 2019.

BACKGROUND: No previous reports have characterized national profiles of soft-tissue sarcoma overall. We examined the nationwide statistics for soft-tissue sarcoma in Japan using data from the population-based National Cancer Registry. METHODS: We identified 23 522 soft-tissue-sarcoma patients who were entered in the National Cancer Registry during 2016-19 using International Classification of Diseases-Oncology, Third Edition codes for cancer topography and morphology. We extracted data on patient demographics, tumor details (reason for diagnosis, tumor location, histology, extent of disease), hospital volume/type, treatment, and prognosis for each patient. RESULTS: Soft-tissue sarcoma showed a slight male preponderance. Approximately 5500-6000 new cases were diagnosed as soft-tissue sarcoma per year, with the age-adjusted incidence of soft-tissue sarcoma being 3.22/100000/year. The age distribution showed a single peak in the 70-79 age range, and sex-stratified data showed it was higher in men. The most common histologic subtype was liposarcoma. The most frequent tumor locations were the soft tissue and skin, followed by the retroperitoneum. Extent of disease was categorized as: "localized" (31.3%), "regional" (38.9%), or "distant" (10.5%). We found significant associations between overall survival and sex, age, tumor location, facility type, hospital volume, reason for diagnosis, extent of disease, and surgical treatment. CONCLUSIONS: This is the first study to outline the epidemiology, clinical features, treatment, prognosis, and significant factors affecting prognosis of soft-tissue sarcoma in Japan using the National Cancer Registry. Documenting our data regarding elderly patients' outcomes is essential so other countries showing similar population-aging trends can learn from our experiences. LEVEL OF EVIDENCE: Prognostic studies, Level III.

Clear cell sarcoma in Japan: an analysis of the population-based cancer registry in Japan.

BACKGROUND: Clear cell sarcoma is rare, so no reports have previously characterized its national profiles. We examined the nationwide epidemiology and clinical outcomes of patients with clear cell sarcoma based on the National Cancer Registry in Japan. METHODS: Overall, 23 522 patients with soft tissue sarcoma-entered in the National Cancer Registry in 2016-2019 using the International Classification of Diseases for Oncology, Third Edition cancer topography and morphology codes-were enrolled in either the clear cell or the non-clear cell sarcoma group. Data extracted included: demographics (sex and age), tumor details (reason for diagnosis, tumor location, histology and stage), hospital volume and facility type, treatment and prognosis for each patient. RESULTS: Of 23 522 soft tissue sarcoma patients, 122 were enrolled in the clear cell sarcoma group and 23 400 in the non-clear cell sarcoma group. The incidence of clear cell sarcoma was 0.52% of all soft tissue sarcoma, with an age-adjusted incidence of 0.024/100 000/year. The age at diagnosis was significantly younger, and more tumors were at the localized stage in the clear cell than the non-clear cell sarcoma group. In addition, the overall survival in the clear cell group was worse than in the non-clear cell group (P < 0.001). Of 122 patients with clear cell sarcoma, the localized stage, surgical treatment and treatment without chemotherapy were associated with better overall survival in the univariate analyses. CONCLUSIONS: The present study is the first to have clarified the epidemiology, clinical features, treatment, prognosis and significant factors affecting the prognosis of patients with clear cell sarcoma in Japan.

Is perioperative chemotherapy effective in patients with localized myxoid liposarcoma?

BACKGROUND: This study aimed to compare the local recurrence, distant metastasis and disease-specific survival rates of patients with localized myxoid liposarcoma in the surgery and adjuvant chemotherapy group versus the surgery alone group. METHODS: A total of 456 patients in the Japanese National Bone and Soft Tissue Tumour Registry database who had localized myxoid liposarcoma and underwent surgery and adjuvant chemotherapy or surgery alone between 2001 and 2019 were included in this retrospective study. The study adjusted for background differences between patients who underwent surgery and adjuvant chemotherapy (n = 228) or surgery alone (n = 228) using propensity score matching. RESULTS: Univariate analysis showed no significant difference in local recurrence rate between the two groups (5-year local recurrence-free survival: 98.6% [95% confidence interval: 95.9-99.6] vs. 94.0% [95% confidence interval: 89.7-96.6], P = 0.052). Univariate analysis showed no difference in the incidence of distant metastases between the two groups (5-year distant metastasis-free survival: 80.5% [95% confidence interval: 73.9-85.8] vs. 75.1% [95% confidence interval: 67.7-81.2], P = 0.508). Univariate analysis showed no difference in disease-specific survival between the two groups (5-year disease-specific survival: 92.6% [95% confidence interval: 86.1-96.2] vs. 93.2% [95% confidence interval: 87.6-96.4], P = 0.804). In the high-risk group (n = 203) with high-grade tumours and tumour size ≥10 cm, there were no significant differences in the local recurrence, distant metastasis and disease-specific survival rates between the surgery and adjuvant chemotherapy group and the surgery alone group. CONCLUSION: The effect of adjuvant chemotherapy on localized myxoid liposarcoma appears to be limited.

Current status of head and neck sarcomas in Japan in 2016-2019: an analysis using the national cancer registry.

BACKGROUND: Head and neck sarcomas are especially rare in Asia, leading to limited clinical evidence. This study aimed to investigate the incidence, clinical features, treatment status, and outcome of these sarcomas using data from the National Cancer Registry in Japan. METHODS: All head and neck sarcomas diagnosed between 2016 and 2019 and recorded in the National Cancer Registry were analyzed. Data on sex, age, primary site, histological type, stage, treatment modality, and prognostic information were collected. Age-adjusted incidence and 3-year survival rates of patients with head and neck sarcomas were calculated. RESULTS: Overall, 635 head and neck sarcoma patients were identified. Head and neck sarcoma occurred more frequently in men and patients in their 70 s. The age-adjusted annual incidence rate was 0.125 per 100,000 patients in the 2015 Japanese model or 0.089 per 100,000 patients in the world population model. The nasal cavity and paranasal sinuses were the most frequent primary sites, with rhabdomyosarcoma as the most common histologic type. Treatment typically involved chemotherapy and/or radiation therapy for rhabdomyosarcoma and Ewing's sarcoma, whereas surgical approaches for other types. Three-year survival rate of head and neck sarcoma patients was 64.8%. CONCLUSIONS: Head and neck sarcomas occurred rarely, but most frequently in the nasal cavity and paranasal sinuses in Japan. Poor outcomes were observed for sarcoma patients than for non-sarcoma head and neck cancer patients.

The diagnostic and prognostic value of tartrate-resistant acid phosphatase isoform 5b for giant cell tumor of bone.

BACKGROUND: Serum level of tartrate-resistant acid phosphatase 5b (TRACP5b) is an excellent serum marker of bone resorption. In patients with giant cell tumor of bone (GCTB), TRACP5b levels are reportedly elevated. This study investigated whether TRACP5b could be a diagnostic serum marker and be useful for detecting postoperative disease progression for GCTB. METHODS: Cohort 1: We abstracted data from 120 patients with TRACP5b measurements from our database: 49 patients with GCTB and 71 patients non-GCTB. We compared serum TRACP5b values between the GCTB and non-GCTB groups. Cohort 2 included 47 patients with GCTB who had more than 6 months of follow-up and multiple TRACP5b values. For patients with local recurrence, TRACP5b change rate was calculated by comparing the TRACP5b value just before progression (a) with the value at the time of progression (b): Change rate = [(b)-(a)]/(a). In the non-progression group, the change rate was calculated from the two consecutive TRACP5b values, (c) and (d): Change rate =[(c)-(d)]/(c). We compared TRACP5b change rates between the progression and non-progression groups. RESULTS: Cohort 1: The GCTB group had a significantly higher mean TRACP5b value (1756 ± 2021 mU/dL) than the non-GCTB group (415 ± 219 mU/dL) (p < 0.0001). Cohort 2: The mean TRACP5b change rate of the progression group was significantly higher than the non-progression group (8.53 ± 8.52 and 0.24 ± 0.27, respectively; p < 0.0001). CONCLUSION: TRACP5b is a useful diagnostic marker in GCTB. The rate of change in serum TRACP5b values is a highly sensitive marker for predicting local recurrence in GCTB.

Statistics of bone sarcoma in Japan: report from the population-based cancer registry in Japan.

BACKGROUND: No previous reports have characterized national bone sarcoma profiles overall. We examined the nationwide statistics for bone sarcoma in Japan using data from the National Cancer Registry (NCR), a population-based cancer registry. METHODS: We identified 3,755 patients with bone sarcomas entered in the NCR during 2016-2019 using International Classification of Diseases-Oncology, Third Edition codes for cancer topography and morphology. We extracted data on patient demographics, tumor details (reason for diagnosis, tumor location, histology, extent of disease), hospital volume/type, treatment, and prognosis for each patient. RESULTS: Bone sarcoma showed a slight male preponderance. The age distribution peaked at ages 10-20 and 60-80; approximately 44% of patients were aged over 60 years. Chordoma, chondrosarcoma, and malignant fibrous histiocytoma of bone peaked in the elderly, and Ewing's sarcoma peaked in children. Osteosarcoma had two peaks in Japan as well as in Western countries. The most frequent tumor locations were the limb (45%) and the pelvis (21%). Extent of disease was categorized as: "localized" (39%), "regional" (27%), and "distant" (11%). We found significant associations between overall survival and age, tumor location, facility type, hospital volume, histologic subtype, reason for diagnosis, and extent of disease. The latter had the poorest survival. CONCLUSIONS: This is the first study to outline the epidemiology, clinical features, treatment, prognosis, and significant factors affecting prognosis of bone sarcoma in Japan using the NCR. Documenting our data regarding elderly patients' outcomes is essential so other countries showing similar population-aging trends can learn from our experiences. LEVEL OF EVIDENCE: Prognostic studies, Level III.

Results of the JRS-I LRA0401 and LRB0402 Japan Rhabdomyosarcoma Study Group trials for low-risk embryonal rhabdomyosarcoma.

BACKGROUND: Failure-free survival (FFS) rates of low-risk patients with rhabdomyosarcoma improved in Intergroup Rhabdomyosarcoma Study IV after the escalation of cyclophosphamide total dose to 26.4 g/m2. However, this dose may increase the risk of adverse events, including infertility, in some patients. The JRS-I LRA0401 and LRB0402 protocols aimed to reduce the cyclophosphamide dose to 9.6 g/m2 and 17.6 g/m2, respectively, without decreasing the FFS rates. METHODS: Subgroup-A patients received eight cycles (24 weeks) of vincristine, actinomycin D, and 1.2 g/m2/cycle cyclophosphamide. Subgroup-B patients received eight cycles (24 weeks) of vincristine, actinomycin D, and 2.2 g/m2/cycle cyclophosphamide, followed by six cycles (24 weeks) of vincristine and actinomycin D. Group II/III patients in both subgroups received radiotherapy. RESULTS: In subgroup A (n = 12), the 3-year FFS rate was 83% (95% confidence interval [CI], 48-96), and the 3-year overall survival (OS) rate was 100%. Only one isolated local recurrence was observed (8.3%). There were no unexpected grade-4 toxicities and no deaths. In subgroup B (n = 16), the 3-year FFS and OS rates were 88% (95% CI, 59-97) and 94% (95% CI, 63-99), respectively. There were no unexpected grade 4 toxicities and no deaths. CONCLUSIONS: Shorter duration therapy using vincristine, actinomycin D, and lower dose cyclophosphamide with or without radiotherapy for patients with low-risk subgroup A rhabdomyosarcoma (JRS-I LRA0401 protocol) and moderate reduction of cyclophosphamide dose for patients with low-risk subgroup B rhabdomyosarcoma (JRS-I LRB0402 protocol) did not compromise FFS.

What Are the Complication Rates and Factors Associated With Total Femur Replacement After Tumor Resection? Findings From the Japanese Musculoskeletal Oncology Group.

BACKGROUND: Patients undergoing massive tumor resection and total femur replacement (TFR) face a substantial risk of hip dislocation and infection, often resulting in multiple implant revisions or hip disarticulation. These complications can impact their independence and prognosis. Additionally, their shorter life expectancy is influenced by challenges in achieving local radical resection and controlling metastases. Identifying suitable candidates for TFR is vital, necessitating investigations into dislocation, infection, implant failure rates, local recurrence, overall survival, and associated factors. QUESTIONS/PURPOSES: (1) What is the postsurgical complication (hip dislocation and infection) rate and factors associated with postsurgical complications in patients who underwent TFR after tumor resection? (2) What is the local recurrence rate, implant failure rate, overall survival rate, and factors associated with local recurrence and implant failure? METHODS: We retrospectively evaluated 42 patients (median [range] age 47 years [10 to 79 years]) who underwent TFR and tumor resection at the time of the same surgical procedure between 1990 and 2020 at 12 registered institutions that specialized in tumor treatment in Japan. A total of 55% (23) of the patients were men, and 79% (33) had bone sarcoma. The median (range) follow-up period was 36.5 months (2 to 327 months). Of the 42 patients, 12% (5) were lost to follow-up before 2 years without meeting a study endpoint (postsurgical complications, revision, or amputation), and another 19% (8) died before 2 years with implants intact, leaving 69% (29) of the original group who had either follow-up of at least 2 years or met a study endpoint before the minimum surveillance duration. Another 10% (4) had a minimum of 2 years of follow-up but had not been seen in the past 5 years. Infection was defined as deep-seated infection involving soft tissues, bones, joints, and the area around the implant. We did not consider superficial infections. Implant failure was defined when a patient underwent reimplantation or amputation. The complication and implant failure rates were assessed by the cumulative incidence function method, considering competing events. The Kaplan-Meier method was used to estimate the overall survival rate. RESULTS: The 1-month, 6-month, 1-year, and 2-year dislocation rates were 5%, 12%, 14%, and 14%, respectively. The 1-month, 6-month, 1-year, and 2-year infection rates were 5%, 7%, 10%, and 15%, respectively. Multivariable analyses for hip dislocation and infection revealed that resection of the abductor muscles and large tumor size were positively associated with hip dislocation. The 6-month, 1-year, and 2-year local recurrence rates were 5%, 15%, and 15%, respectively. The 6-month, 1-year, 2-year, and 5-year implant failure rates were 5% (95% confidence interval 1% to 15%), 7% (95% CI 2% to 18%), 16% (95% CI 6% to 29%), and 16% (95% CI 6% to 29%), respectively. Multivariable analyses of local recurrence and implant failure that led to reimplantation or amputation revealed that a positive surgical margin was positively associated with local recurrence. The 1-year, 2-year, and 5-year overall patient survival rates were 95% (95% CI 87% to 102%), 77% (95% CI 64% to 91%), and 64% (95% CI 48% to 81%), respectively. CONCLUSION: Hip dislocation, infection, and local recurrence were frequently observed in patients who received massive tumor resection and TFR in our study, eventually leading to reimplantation or amputation. Preserving the abductor muscles and resecting the tumor with a wide margin can prevent postoperative dislocation and local recurrence. Future research should focus on patient selection criteria, prevention of hip dislocation, and innovative treatments. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Infection of surgery for bone and soft tissue sarcoma with biological reconstruction: Data from the Japanese nationwide bone tumor registry.

BACKGROUND: Although biological reconstruction (such as recycled autograft, vascularized autograft, allograft, or bone transport) is possible for bone defects after malignant bone or soft tissue tumor resection, a high incidence of postoperative complications, including infection, poses a problem. The difficulty in accumulating cases has resulted in a lack of reliable etiological information, such as the incidence and risk factors of postoperative infections. METHODS: We conducted a retrospective study on the nationwide registry data. The primary endpoint was the need for additional surgical intervention for infection control. The overall incidence of postoperative infection and the related risk factors were analyzed. RESULTS: We included 707 malignant bone and soft tissue tumors with biological reconstruction, including recycled autograft, vascularized autograft, allograft, bone transport, and combinations of these. The incidence of postoperative infection was 10.8%. Patients reconstructed by pedicled autograft showed a higher incidence of infection, while cases involving the combination of recycled and pedicled autograft or allograft showed a lower incidence. Independent risk factors for infection included age over 17, tumor diameter over 10 cm, the tumor located on the trunk or being high grade, reconstruction by pedicled autograft, and delayed wound healing. CONCLUSION: Infection incidence was comparable to those in previous reports. Several conventional and novel risk factors were extracted by administering nationwide registry data. Data from the nationwide registry was informative for analyzing the incidence of postoperative infection in biological reconstruction with malignant bone and soft tissue tumor resection.

Japanese orthopaedic association (JOA) clinical practice guidelines on the management of malignant bone tumors - Secondary publication.

BACKGROUND: In Japan, there are currently no general guidelines for the treatment of primary malignant bone tumors. Therefore, the Japanese Orthopaedic Association established a committee to develop guidelines for the appropriate diagnosis and treatment of primary malignant bone tumors for medical professionals in clinical practice. METHODS: The guidelines were developed in accordance with "Minds Clinical Practice Guideline Development Handbook 2014″ and "Minds Clinical Practice Guideline Development Manual 2017". The Japanese Orthopaedic Association's Bone and Soft Tissue Tumor Committee established guideline development and systematic review committees, drawing members from orthopedic specialists leading the diagnosis and treatment of bone and soft tissue tumors. Pediatricians, radiologists, and diagnostic pathologists were added to both committees because of the importance of multidisciplinary treatment. Based on the diagnosis and treatment algorithm for primary malignant bone tumors, important decision-making points were selected, and clinical questions (CQ) were determined. The strength of recommendation was rated on two levels and the strength of evidence was rated on four levels. The recommendations published were selected based on agreement by 70% or more of the voters. RESULTS: The guideline development committee examined the important clinical issues in the clinical algorithm and selected 22 CQs. The systematic review committee reviewed the evidence concerning each CQ and a clinical value judgment was added by experts. Eventually, 25 questions were published and the text of each recommendation was determined. CONCLUSION: Since primary malignant bone tumors are rare, there is a dearth of strong evidence based on randomized controlled trials, and recommendations cannot be applied to all the patients. In clinical practice, appropriate treatment of patients with primary malignant bone tumors should be based on the histopathological diagnosis and degree of progression of each case, using these guidelines as a reference.

IDH-negative chondrosarcoma with metachronous dedifferentiation only in the metastatic site-A diagnostic pitfall.

Dedifferentiated chondrosarcoma is a subtype of chondrosarcoma with a biphasic histological appearance of a chondrosarcoma component transitioning to a high-grade, noncartilaginous sarcoma. It is particularly difficult to confirm the diagnosis when a sarcoma lacking cartilaginous component occurs at a distant location from the primary lesion. The patient was a 72-year-old woman with multiple lesions in the pelvis, lungs, and liver, 18 months after resection of grade 2 central chondrosarcoma of the sternum. Imaging showed no cartilage component in any location. Although a needle biopsy from the pelvic region confirmed the diagnosis as high-grade sarcoma without a cartilage component, it was difficult to distinguish between a new primary sarcoma and metachronous metastatic lesions from patient's known prior dedifferentiated chondrosarcoma. We therefore performed a comparative molecular analysis by whole-exome sequencing of the biopsy sample and the resected sternal central chondrosarcoma. Both lesions had no IDH1/2 mutations but shared 19 somatic mutations and wide-range chromosomal losses, indicating similar origin. This case illustrates the challenge is coupling a diagnosis of metastatic dedifferentiated chondrosarcoma when no chondroid component is evident. Our study also highlights the benefit of genomic analysis in this differential diagnosis, especially in the context of dedifferentiated chondrosarcoma lacking IDH1/2 mutations.