A European consensus recommendation on the management of delayed methotrexate elimination: supportive measures, leucovorin rescue and glucarpidase treatment.

High-dose methotrexate (HDMTX) is used in the treatment of a range of adult and childhood cancers. Although HDMTX can provide effective anti-tumor activity with an acceptable safety profile for most patients, delayed methotrexate elimination (DME) develops in a minority of patients receiving HDMTX and may be accompanied by renal dysfunction and potentially life-threatening toxicity. A panel of European physicians with experience in the use of HDMTX as well as of glucarpidase convened to develop a series of consensus statements to provide practical guidance on the prevention and treatment of DME, including the use of glucarpidase. Robust implementation of supportive measures including hyperhydration and urine alkalinization emerged as critical in order to reduce the risk of DME with HDMTX treatment, with leucovorin rescue critical in reducing the risk of DME complications. Early recognition of DME is important to promptly implement appropriate treatment including, intensified hydration, high-dose leucovorin and, when appropriate, glucarpidase.

Osteosarcoma as a secondary malignancy following rhabdomyosarcoma: A report of 28 affected patients from the Cooperative Osteosarcoma Study Group (COSS).

BACKGROUND: Osteosarcoma may arise as a secondary malignancy following rhabdomyosarcoma (RMS). We utilized the Cooperative Osteosarcoma Study Group (COSS) database to better understand this association. PATIENTS AND METHODS: The COSS database (1980-05/2023) was searched for patients whose osteosarcoma was preceded by RMS. Eligible patients were analyzed for patient-, tumor-, and treatment-related variables as well as outcomes. RESULTS: The search revealed 28 eligible osteosarcomas (27 high-grade central, one periosteal; male:female = 16:12; median age RMS 2.1 [range: 0.9-10.0] years, osteosarcoma 13.5 [7.2-29.0] years). Genetic tumor-predisposition syndromes were documented in 12 patients. One patient had had a distinct malignancy prior to RMS, two intermittently, seven following osteosarcoma. Local RMS treatment had included radiotherapy in 20/26 cases (two unknown). Secondary osteosarcoma sites were extremity 13, trunk seven, head and neck eight; 15 osteosarcomas were radiation-associated. There was only one case of primary osteosarcoma metastases. Osteosarcoma treatment included chemotherapy (27), surgery (26), or radiotherapy (2). A macroscopically complete remission of all osteosarcoma sites was achieved in 24 cases. Median follow-up was 5.8 (range: 0.5-18.4) years after osteosarcoma and 8.1 (1.0-15.4) years for 14 survivors. Actuarial 5-year overall and event-free survival were 66% (standard error 9%) and 45% (10%), respectively. Five of 14 deaths were caused by further malignancies. CONCLUSION: This series offers a benchmark for patients who develop a secondary osteosarcoma after RMS. Affected patients are generally still in the pediatric age. The results obtained strongly argue for genetic predisposition testing in RMS and against therapeutic leniency in comparable situations.

Beyond 5-year survival. A report from the Cooperative Osteosarcoma Study Group (COSS).

PURPOSE: Prognostic factors have been well described for osteosarcoma, but analyses evaluating the further course of long-term survivors are lacking. We used the large database of the Cooperative Osteosarcoma Study Group (COSS) to perform such an analysis. PATIENTS AND METHODS: The COSS database 1980-04/2019 was searched for 5-year survivors of primary high-grade central osteosarcoma of the extremities or trunk. Identified patients were analyzed for their further survival outcomes, assessing potentially prognostic and predictive factors already evident at initial disease presentation and treatment as well as their disease course during the first 5 years of follow-up. RESULTS: Two thousand and nine former eligible patients were identified (median age at initial diagnosis 15.1 (2.5-63.0) years; male vs. female 1149 (57.2%) vs. 860 (42.8%); extremities vs. trunk 1927 (95.9%) vs. 82 (4.1%); extremity primaries <1/3 vs. ≥1/3 of the involved bone 997 (67.8%) vs. 474 (32.2%) (456 unknown); localized vs. primary metastatic 1881 (93.6%) vs. 128 (6.4%); osteosarcoma as a secondary malignancy 41/2009 (2.0%)). Therapy starting by chemotherapy versus primary surgery 1860 (92.6%) versus 149 (7.4%); definitive tumor surgery by limb salvage versus ablative 1347 (67.0%) versus 659 (1 no surgery, 2 unknown); tumor response to preoperative chemotherapy documented for 1765 (94.9%) patients receiving neoadjuvant chemotherapy, good (<10% viable tumor) versus poor 1130 (64.0%) versus 635 (36.0%), local radiotherapy documented for 19 (0.9%) tumors. Recurrence during preceding 5 years no versus yes 1681 (83.7%) versus 328 (16.3%). Median follow-up starting 5 years after initial diagnosis 6.1 (0.002-32.2) years; 1815 survivors and 194 deaths. Overall survival after another 5/10/15/20 years 91.7%/88.9%/85.8%/83.4% for all patients; 97.5%/95.2%/92.4%/89.9% if in remission years 1-5 versus 62.7%/57.3%/53.0%/51.2% if recurrence year 1-5 (p < 0.001). Significant predictors of survival for all patients age at diagnosis (p = 0.038), tumor site (p = 0.030), having experienced the osteosarcoma as secondary malignancy (p < 0.001), tumor response to preoperative chemotherapy (p = 0.002). Multivariate Cox regression testing possible for 1759 (87.6%) patients with complete dataset: Having had a recurrence in years 1-5 (p < 0.001), older age at diagnosis (p = 0.009), and osteosarcoma as secondary malignancy (p = 0.013) retained significance. DISCUSSION: Highly important predictors of death such as the extent of tumor response to chemotherapy no longer remain valid after 5-year survival. The individual history of malignancies and their outcomes seems to gain pivotal importance. CONCLUSION: This benchmark analysis clearly defined risk factors for the further course of 5-year survivors from osteosarcoma. It argues for large disease-oriented databases as well as for very long follow-up periods. Novel findings will most likely require innovative statistical models to analyze such cohorts.

Biological Sample Collection to Advance Research and Treatment: A Fight Osteosarcoma Through European Research and Euro Ewing Consortium Statement.

Osteosarcoma and Ewing sarcoma are bone tumors mostly diagnosed in children, adolescents, and young adults. Despite multimodal therapy, morbidity is high and survival rates remain low, especially in the metastatic disease setting. Trials investigating targeted therapies and immunotherapies have not been groundbreaking. Better understanding of biological subgroups, the role of the tumor immune microenvironment, factors that promote metastasis, and clinical biomarkers of prognosis and drug response are required to make progress. A prerequisite to achieve desired success is a thorough, systematic, and clinically linked biological analysis of patient samples, but disease rarity and tissue processing challenges such as logistics and infrastructure have contributed to a lack of relevant samples for clinical care and research. There is a need for a Europe-wide framework to be implemented for the adequate and minimal sampling, processing, storage, and analysis of patient samples. Two international panels of scientists, clinicians, and patient and parent advocates have formed the Fight Osteosarcoma Through European Research consortium and the Euro Ewing Consortium. The consortia shared their expertise and institutional practices to formulate new guidelines. We report new reference standards for adequate and minimally required sampling (time points, diagnostic samples, and liquid biopsy tubes), handling, and biobanking to enable advanced biological studies in bone sarcoma. We describe standards for analysis and annotation to drive collaboration and data harmonization with practical, legal, and ethical considerations. This position paper provides comprehensive guidelines that should become the new standards of care that will accelerate scientific progress, promote collaboration, and improve outcomes.

Osteosarcoma Arising as a Secondary Malignancy following Treatment for Hematologic Cancer: A Report of 33 Affected Patients from the Cooperative Osteosarcoma Study Group (COSS).

PURPOSE: Osteosarcoma may arise as a secondary cancer following leukemias or lymphomas. We intended to increase the knowledge about such rare events. PATIENTS AND METHODS: We searched the Cooperative Osteosarcoma Study Group's database for individuals who developed their osteosarcoma following a previous hematological malignancy. The presentation and treatment of both malignancies was investigated, and additional neoplasms were noted. Outcomes after osteosarcoma were analyzed and potential prognostic factors were searched for. RESULTS: A total of 33 eligible patients were identified (male: 23, female: 10; median age: 12.9 years at diagnosis of hematological cancer; 20 lymphomas, 13 leukemias). A cancer predisposition syndrome was evident in one patient only. The hematological cancers had been treated by radiotherapy in 28 (1 unknown) and chemotherapy in 26 cases, including bone-marrow transplantation in 9. The secondary bone sarcomas (high-grade central 27, periosteal 2, extra-osseous 2, undifferentiated pleomorphic sarcoma of bone 2) arose after a median lag-time of 9.4 years, when patients were a median of 19.1 years old. Tumors were considered radiation-related in 26 cases (1 unknown). Osteosarcoma-sites were in the extremities (19), trunk (12), or head and neck (2). Metastases at diagnosis affected eight patients. Information on osteosarcoma therapy was available for 31 cases. All of these received chemotherapy. Local therapy involved surgery in 27 patients, with a good response reported for 9/18 eligible patients. Local radiotherapy was given to three patients. The median follow-up was 3.9 (0.3-12.0) years after bone tumor diagnosis. During this period, 21 patients had developed events as defined, and 15 had died, resulting in 5-year event-free and overall survival rates of 40% (standard error: 9%) and 56% (10%), respectively. There were multiple instances of additional neoplasms. Several factors were found to be of prognostic value (p < 0.05) for event-free (osteosarcoma site in the extremities) or overall (achievement of a surgical osteosarcoma-remission, receiving chemotherapy for the hematologic malignancy) survival. CONCLUSIONS: We were able to prove radiation therapy for hematological malignancies to be the predominant risk factor for later osteosarcomas. A resulting overrepresentation of axial and a tendency towards additional neoplasms affects prognosis. Still, selected patients may become long-term survivors with appropriate therapies, which is an argument against therapeutic negligence.

Primary Multi-Systemic Metastases in Osteosarcoma: Presentation, Treatment, and Survival of 83 Patients of the Cooperative Osteosarcoma Study Group.

BACKGROUND: To evaluate patient and tumour characteristics, treatment, and their impact on survival in patients with multi-systemic metastases at initial diagnosis of high-grade osteosarcoma. Precedure: Eighty-three consecutive patients who presented with multi-systemic metastases at initial diagnosis of high-grade osteosarcoma were retrospectively reviewed. In cases of curative intent, the Cooperative Osteosarcoma Study Group recommended surgical removal of all detectable metastases in addition to complete resection of the primary tumour and chemotherapy. RESULTS: Eighty-three eligible patients (1.8%) were identified among a total of 4605 individuals with high-grade osteosarcoma. Nine (10.8%) of these achieved complete surgical remission, of whom seven later had recurrences. The median follow-up time was 12 (range, 1-165) months for all patients. Actuarial event-free survival after 1, 2, and 5 years was 9.6 ± 3.2%, 1.4 ± 1.4%, and 1.4 ± 1.4%, and overall survival was 54.0 ± 5.6%, 23.2 ± 4.9%, and 8.7 ± 3.3%. In univariate analyses, elevated alkaline phosphatase before chemotherapy, pleural effusion, distant bones as metastatic sites, and more than one bone metastasis were negative prognostic factors. Among treatment-related factors, the microscopically complete resection of the primary tumour, a good response to first-line chemotherapy, the macroscopically complete resection of all affected tumour sites, and local treatment (surgery ± radiotherapy) of all bone metastases were associated with better outcomes. Tumour progression under first-line treatment significantly correlated with shorter survival times. CONCLUSION: The outlook for patients with multi-systemic primary metastases from osteosarcoma remains very poor. The utmost importance of surgical resection of all tumour sites was confirmed. For unresectable bone metastases, radiotherapy might be considered. In the patient group studied, standard chemotherapy was often insufficiently effective. In the case of such advanced disease, alternative treatment options are urgently required.

Combined Immunotherapy Improves Outcome for Replication-Repair-Deficient (RRD) High-Grade Glioma Failing Anti-PD-1 Monotherapy: A Report from the International RRD Consortium.

Immune checkpoint inhibition (ICI) is effective for replication-repair-deficient, high-grade gliomas (RRD-HGG). The clinical/biological impact of immune-directed approaches after failing ICI monotherapy is unknown. We performed an international study on 75 patients treated with anti-PD-1; 20 are progression free (median follow-up, 3.7 years). After second progression/recurrence (n = 55), continuing ICI-based salvage prolonged survival to 11.6 months (n = 38; P < 0.001), particularly for those with extreme mutation burden (P = 0.03). Delayed, sustained responses were observed, associated with changes in mutational spectra and the immune microenvironment. Response to reirradiation was explained by an absence of deleterious postradiation indel signatures (ID8). CTLA4 expression increased over time, and subsequent CTLA4 inhibition resulted in response/stable disease in 75%. RAS-MAPK-pathway inhibition led to the reinvigoration of peripheral immune and radiologic responses. Local (flare) and systemic immune adverse events were frequent (biallelic mismatch-repair deficiency > Lynch syndrome). We provide a mechanistic rationale for the sustained benefit in RRD-HGG from immune-directed/synergistic salvage therapies. Future approaches need to be tailored to patient and tumor biology. SIGNIFICANCE: Hypermutant RRD-HGG are susceptible to checkpoint inhibitors beyond initial progression, leading to improved survival when reirradiation and synergistic immune/targeted agents are added. This is driven by their unique biological and immune properties, which evolve over time. Future research should focus on combinatorial regimens that increase patient survival while limiting immune toxicity. This article is featured in Selected Articles from This Issue, p. 201.

Osteosarcoma Arising After Ewing Sarcoma or Vice Versa: A Report of 20 Affected Patients from the Cooperative Osteosarcoma Study Group (COSS).

BACKGROUND/AIM: Ewing sarcoma can arise in patients after osteosarcoma or vice versa. Our aim was to learn more about which patients develop these secondary tumors, which treatments may be effective, and which patients might survive. PATIENTS AND METHODS: The database of the Cooperative Osteosarcoma Study Group (1980-09/2022) was searched for all patients with an osteosarcoma (including undifferentiated pleomorphic sarcoma of the bone) who also suffered from Ewing sarcoma (incl. peripheral neuroectodermal tumor) at any time, previously or thereafter. The identified patients were then analyzed for patient, tumor, and treatment-related variables as well as their disease- and survival-status at the last follow-up. RESULTS: A total of 20 eligible patients [17 Ewing sarcoma prior to osteosarcoma, 3 vice versa; 10 males, 10 females; median age at 1st cancer 10.5 (2.4-20.6), at 2nd cancer 20.5 (9.9-42.4) years] were identified. None of the patients developed a 3rd cancer and none had a known tumor-predisposition syndrome. Sixteen/17 secondary osteosarcomas and no secondary Ewing sarcoma developed in sites that had previously been irradiated. Nineteen/20 (95%) patients received primary multi-agent chemotherapy for their 1st and 2nd cancers. Actuarial overall and event-free survival probabilities at five years after the diagnosis of the secondary cancer were 69% and 42%, respectively. CONCLUSION: Secondary osteosarcoma arising after Ewing sarcoma is almost exclusively associated with radiation. This is not the case vice versa. Either way, long-term survival is a realistic possibility with appropriate multidisciplinary treatment; thus, therapeutic negligence is clearly inadequate.

Prognostic Factors in High-Grade Osteosarcoma of theExtremities or Trunk: An Analysis of 1,702 Patients Treatedon Neoadjuvant Cooperative Osteosarcoma Study GroupProtocols.

PURPOSE: To define prognostic factors for response and long-term outcome for a wide spectrum of osteosarcomas, extending well beyond those of the typical young patient with seemingly localized extremity disease. PATIENTS AND METHODS: A total of 1,702 consecutive newly diagnosed patients with high-grade osteosarcoma of the trunk or limbs registered into the neoadjuvant studies of the Cooperative Osteosarcoma Study Group before July 1998 were entered into an analysis of demographic, tumor-related, and treatment-related variables, response, and survival. The intended therapeutic strategy included preoperative and postoperative chemotherapy with multiple agents as well as surgery of all operable lesions. RESULTS: Axial tumor site, male sex, and a long history of symptoms were associated with poor response to chemotherapy in univariate and multivariate analysis. Actuarial 10-year overall and event-free survival rates were 59.8% and 48.9%. Among the variables assessable at diagnosis, patient age (actuarial 10-year survival ≥ 40, 41.6%; < 40, 60.2%; P = .012), tumor site (axial, 29.2%; limb, 61.7%; P < .0001), and primary metastases (yes, 26.7%; no, 64.4%; P < .0001), and for extremity osteosarcomas, also size (≥ one third, 52.5%; < one third, 66.7%; P < .0001) and location within the limb (proximal, 49.3%; other, 63.9%; P < .0001), had significant influence on outcome. Two additional important prognostic factors were treatment related: response to chemotherapy (poor, 47.2%; good, 73.4%; P < .0001) and the extent of surgery (incomplete, 14.6%; macroscopically complete, 64.8%; P < .0001). All factors except age maintained their significance in multivariate testing, with surgical remission and histologic response emerging as the key prognostic factors. CONCLUSION: Tumor site and size, primary metastases, response to chemotherapy, and surgical remission are of independent prognostic value in osteosarcoma.

Outcome of rare primary malignant bone sarcoma treated with multimodal therapy: Results from the EUROpean Bone Over 40 Sarcoma Study (EURO-B.O.S.S.).

BACKGROUND: Rare primary malignant bone sarcomas (RPMBS) account for 5%-10% of primary high-grade bone tumors and represent a major treatment challenge. The outcome of patients with RPMBS enrolled in the EUROpean Bone Over 40 Sarcoma Study (EURO-B.O.S.S) is presented. METHODS: Inclusion criteria were as follows: age from 41 to 65 years and a diagnosis of high-grade spindle cell, pleomorphic, or vascular RPMBS. The chemotherapy regimen included doxorubicin 60 mg/m2 , ifosfamide 9 g/m2 , and cisplatin 90 mg/m2 ; postoperative methotrexate 8 g/m2 was added in case of a poor histologic response. Version 2.0 of the Common Terminology Criteria for Adverse Events, Kaplan-Meier curves, log-rank tests, and univariate Cox regression models were used. RESULTS: In total, 113 patients were evaluable for analysis. The median patient age was 52 years (range, 40-66 years), and 67 patients were men. Eighty-eight tumors were categorized as undifferentiated pleomorphic sarcomas (UPS), 20 were categorized as leiomyosarcomas, three were categorized as fibrosarcomas, and two were categorized as angiosarcomas. Eighty-three of 113 tumors were located in the extremities. Ninety-five of 113 patients presented with no evidence of metastases. After a median follow-up of 6.8 years (interquartile range [IQR], 3.5-9.8 years), the 5-year overall survival rate for patients with localized disease was 68.4% (IQR, 56.9%-77.5%), and it was 71.7% (IQR, 58.1%-81.6%) for patients with UPS and 54.9% (IQR, 29.5%-74.5%) for patients with leiomyosarcoma. Grade III-IV hematologic toxicity was reported in 81% patients; 23% had grade II-III neurotoxicity, and 37.5% had grade I-II nephrotoxicity. Five-year overall survival was significantly better for patients with localized disease, for patients who obtained surgical complete remission, and when the primary tumor was located in the extremities. CONCLUSIONS: The survival of patients who had RPMBS in the current series was similar to that of age-matched patients who had high-grade osteosarcoma treated according to the same protocol. An osteosarcoma-like chemotherapy may be proposed in patients who have RPMBS.

Solitary pulmonary metastases at first recurrence of osteosarcoma: Presentation, treatment, and survival of 219 patients of the Cooperative Osteosarcoma Study Group.

BACKGROUND: To evaluate patient and tumour characteristics, treatment and their impact on survival in patients with a solitary pulmonary metastasis at first relapse of high-grade osteosarcoma. PROCEDURE: Two-hundred and nineteen consecutive patients who had achieved a complete surgical remission and then developed a solitary pulmonary metastasis at first recurrence of high-grade osteosarcoma were retrospectively reviewed. RESULTS: Two hundred and three (94.9%) of 214 patients achieved a second complete remission. After a median time from initial diagnosis of osteosarcoma to first relapse of 2.3 years (range, 0.3-18.8 years), actuarial post-relapse overall survival after 2 and 5 years was 72.0% and 51.2%. Post-relapse event-free survival was 39.1% and 31.1%. Median follow-up time was 3.2 years (range, 0.1-29.4 years). A longer time until first relapse and diagnosis due to imaging were positive prognostic factors in uni- and multivariate analyses, as were a second complete surgical remission and, in regard to death, the absence of a subsequent relapse. The use of salvage chemotherapy and radiotherapy were not associated with patient outcomes, nor was the surgical approach (thoracoscopy vs. thoracotomy) nor the exploration (uni- vs. bilateral). CONCLUSION: Approximately half of the patients who experience a solitary pulmonary relapse at first recurrence of osteosarcoma remain alive 5 years after this first relapse. Only one third will remain disease-free. A complete surgical resection of the lesion is essential for long-term survival while relapse chemotherapy does not seem to improve survival. Innovative therapies are required to improve outcomes.

Establishment, Maintenance, and Performance of the Cooperative Osteosarcoma Study Group (COSS).

INTRODUCTION: Osteosarcoma treatment has benefitted greatly from collaborative research. This paper describes the history and accomplishments of the Cooperative Osteosarcoma Study Group (COSS), mainly dedicated to clinical questions, as well as remaining challenges. MATERIALS AND METHODS: Narrative review of over four decades of uninterrupted collaboration within the multi-national German-Austrian-Swiss COSS group. RESULTS: Since its very first prospective osteosarcoma trial starting in 1977, COSS has continuously been able to provide high-level evidence on various tumor- and treatment-related questions. This includes both the cohort of patients enrolled into prospective trials as well as those patients excluded from them for various reasons, followed in a prospective registry. Well over one hundred disease-related publications attest to the group's impact on the field. Despite these accomplishments, challenging problems remain. DISCUSSION: Collaborative research within a multi-national study group resulted in better definitions of important aspects of the most common bone tumor, osteosarcoma, and its treatments. Important challenges continue to persist.

Primary osteosarcoma of the ribs: A report from the Cooperative Osteosarcoma Study Group.

PURPOSE: Primary rib osteosarcoma has not been investigated extensively, and clinical characteristics and optimal therapeutic strategies have not been defined. The authors used the database of the Cooperative Osteosarcoma Study Group (COSS) to analyze this tumor-site in depth. METHODS: The COSS database was searched for treatment-naive, high-grade osteosarcomas of the rib. Affected patients were analyzed for demographic and tumor-related factors, treatments, and outcomes. RESULTS: A total of 44 patients (23 males, 21 females; median age, 23 years [range, 6-59]) were identified. Primary metastases were detected in six of 44 (14%) patients. Surgery was performed in 40 of 44 (91%) patients and rendered 35 of 44 (80%) patients macroscopically disease-free. Chemotherapy was known to have been administered in 43 of 44 (98%) patients and radiotherapy in seven of 42 (17%) (no data for two patients). A good response to chemotherapy was only noted in five (33%) of those 15 evaluable patients who had received any preoperative chemotherapy. After a median follow-up of 2.49 (0.22-40.35) years for all patients and 6.61 (0.25-40.35) years for 26 survivors (21 of these in first complete remission), 5-year actuarial overall and event-free survival were 53.0% (8.5%) and 42.2% (8.1%), respectively. Incomplete tumor surgery was the most notable negative prognostic factor. Osteoblastic histology and a poor response to chemotherapy may have contributed. CONCLUSION: This large series provides evidence that patients with costal primaries are older than the average osteosarcoma patient, but appear to share the similar tumor biology and-if treated according to standard protocols-prognostic factors with tumors of other sites. Early, preoperative diagnosis and permanent, definitive local control remain major challenges and should contribute to improved outcomes.

Osteosarcomas in older adults: A report from the Cooperative Osteosarcoma Study Group.

INTRODUCTION: Osteosarcoma is typically a disease of the young, but may affect any age. Little is known about the disease in older patients beyond retirement age. We aim to describe the characteristics, treatment, and outcomes of older adult patients registered with our cooperative group. MATERIALS AND METHODS: The database of the Cooperative Osteosarcoma Study Group (COSS) was searched for osteosarcoma patients diagnosed from 1980 to 2020 who were aged 65 years or older at diagnosis. Affected individuals were analyzed for presenting factors, treatments employed, and outcomes. RESULTS: Fifty-five eligible patients were detected (median age 68 [range: 65-84] years; male:female = 25:30). Among these patients, 15/55 (27%) tumors were secondary malignancies, 41/55 (75%) were high-grade central, 4/55 (7%) surface, and 10/55 (18%) extraosseous malignancies, and all but three high-grade. Primary metastases were present in 15/55 (27%) patients. Surgery was reported for 46/55 (84%) patients, radiotherapy for 6/54 (11%, 1 unknown), chemotherapy for 42/50 (84%, 5 unknown). A complete surgical remission was achieved in 31/55 (56%). There were two toxic deaths. With a median follow-up of 1.7 (range: 0.1-18.0) years for all 55 patients and 2.2 (0.1-12.4) years for 24 survivors, event-free and overall survival at 2/5 years were 39.6% (standard error: 6.8%) / 24.5% (6.5%) and 62.0% (7.1%) / 32.7% (7.5%), respectively. Tumor site, metastatic status, surgery, and a complete surgical remission were prognostic for event-free and/or overall survival. DISCUSSION: Osteosarcomas can occur in older individuals. It is more often secondary, axially located, or extraosseous than in younger patients. However, the same treatment principles seem to apply, and selected patients may be cured. Multi-center cooperation is encouraged, thereby gathering expertise for such a rare disease presentation.

Ultra-Late Osteosarcoma Recurrences: An Analysis of 17 Cooperative Osteosarcoma Study Group Patients with a First Recurrence Detected More Than 10 Years After Primary Tumor Diagnosis.

Purpose: Osteosarcoma is a typical malignancy of childhood and adolescence. Recurrences usually occur early, but rarely may arise after decades of remission. Little is known about these very late events and we set out to fill this knowledge gap. Methods: The database of the Cooperative Osteosarcoma Study Group (COSS) was searched for patients with a first recurrence of a high-grade central osteosarcoma occurring >10 years after diagnosis of the primary disease. Identified patients were analyzed for demographic, tumor-, and treatment-related factors as well as outcomes. Results: Among a total of 1,178 10-year relapse-free survivors, 17 affected patients were identified. Only five of these had a documented good response to initial chemotherapy. No presenting factor was identified to predict these very late events. Prognosis was generally very poor despite intensive multimodal therapy. Inoperability of the recurrences seems to have constituted a major limiting factor. Conclusion: Osteosarcoma patients should be followed for potential recurrences for well >10 years from initial diagnosis. Only through such an extended truly long-term follow-up and a structured transition of young patients can these be detected while they are still operable and, hence, potentially curable.

Osteosarcoma pre-diagnosed as another tumor: a report from the Cooperative Osteosarcoma Study Group (COSS).

PURPOSE: The course of osteosarcoma patients primarily treated as such has been well described. Little, however, is known about patients who were primarily treated assuming a different tumor diagnosis. METHODS: The database of the Cooperative Osteosarcoma Study Group COSS was searched (4.435 primary high-grade central osteosarcomas registered prior to 01/01/21). A different tumor entity had to have been assumed for at least one month after the initial diagnostic procedure before the correct diagnosis of osteosarcoma was finally made. Identified patients were analyzed for demographic, tumor-, and treatment-related factors as well as for survival outcomes. RESULTS: 37 patients were identified. They were a median of 19.7 (2.7-60.4) years old at first presentation and were more likely to be females than males (23:14). Bone cysts (n = 8), giant cell tumor of bone (n = 6), and osteoblastoma (n = 6) were the most frequent of 29/37 (78%) benign, chondrosarcoma and its variants (n = 6) the most frequent of 8/37 (22%) malignant original diagnoses. Tumors affected the extremities in 23 (62%), the trunk in 11 (30%), and the craniofacial bones in 3 (8%). Only one patient received systemic treatment while assuming the different diagnosis (1/37, 3%). The median time until the correct diagnosis of osteosarcoma was made was 8 months (range: 1 month-14.1 years). At that time, 6/37 (16%) presented with metastatic disease. All patients went on to receive chemotherapy, 17/37 (46%) neo-adjuvantly. Histologic response was only evaluated in 13/17 (76%) patients and was good (< 10% viable tumor) in only 4/13 (31%) patients. In 31/37 (84%) patients, a surgically complete resection of all macroscopically identified tumor manifestations could be achieved. Five-year overall and event-free survival rates at 5 years were 50.2% (standard error: 8.6%) and 42.6% (8.5%), respectively. CONCLUSION: Osteosarcoma may initially be misdiagnosed and hence subjected to inappropriate treatment including misguided surgery. Once diagnosed correctly, some of the affected patients may still be cured if finally treated according to modern osteosarcoma standards.

Osteosarcoma.

Osteosarcoma is the most common primary malignant tumour of the bone. Osteosarcoma incidence is bimodal, peaking at 18 and 60 years of age, and is slightly more common in males. The key pathophysiological mechanism involves several possible genetic drivers of disease linked to bone formation, causing malignant progression and metastasis. While there have been significant improvements in the outcome of patients with localized disease, with event-free survival outcomes exceeding 60%, in patients with metastatic disease, event-free survival outcomes remain poor at less than 30%. The suspicion of osteosarcoma based on radiographs still requires pathological evaluation of a bone biopsy specimen for definitive diagnosis and CT imaging of the chest should be performed to identify lung nodules. So far, population-based screening and surveillance strategies have not been implemented due to the rarity of osteosarcoma and the lack of reliable markers. Current screening focuses only on groups at high risk such as patients with genetic cancer predisposition syndromes. Management of osteosarcoma requires a multidisciplinary team of paediatric and medical oncologists, orthopaedic and general surgeons, pathologists, radiologists and specialist nurses. Survivors of osteosarcoma require specialized medical follow-up, as curative treatment consisting of chemotherapy and surgery has long-term adverse effects, which also affect the quality of life of patients. The development of osteosarcoma model systems and related research as well as the evaluation of new treatment approaches are ongoing to improve disease outcomes, especially for patients with metastases.

Osteosarcoma and causes of death: A report of 1520 deceased patients from the Cooperative Osteosarcoma Study Group (COSS).

PURPOSE: Most aspects of osteosarcoma have been addressed in detail, but there is no comprehensive analysis of deceased patients and causes of death. METHODS: The database of the Cooperative Osteosarcoma Study Group COSS (1980-03/31/2021; 4475 registered high-grade central osteosarcoma patients) was searched deaths from any cause. Affected patients were analyzed for demographic and baseline variables and disease-status at the time of demise. Deaths from causes other than osteosarcoma were analyzed in detail. RESULTS: A total of 1520 deceased patients were identified (median age (range) at osteosarcoma diagnosis 16 (2-78) years; 908 (59.7%) male, 612 (40.3%) female; primary tumor: extremities 1263 (83.1%), trunk 208 (13.7%), craniofacial 47 (3.1%) (site unknown 2); metastases at registration: absent 1.051 (69.1%), present 466 (30.7%) (3 no data). The median time from diagnosis to death was 2.22 (0.08-32.02) years. 1286 (84.6%) patients succumbed to osteosarcoma (370 without achieving complete remission, 488 first, 428 more than one recurrences), 146 (9.6%) to other, 88 (5.8%) to unknown causes. Chemotherapy-related infections (40), secondary malignancies (39), and perioperative complications (19) were among the most frequent potentially treatment-related causes, and high-dose methotrexate (19), doxorubicin (17), and ifosfamide (15) were the drugs most commonly held responsible. Patients with unknown causes of death had an unusually long median follow-up. CONCLUSION: The major cause of death of patients after osteosarcoma is this malignancy, mostly from one of its multiple relapses. However, almost 10% of fatalities are due to other documented causes. Some of these deaths may be preventable with the knowledge gained from comprehensive analyses such as this.

Systemic treatment for primary malignant sarcomas arising in craniofacial bones.

Introduction: Craniofacial bones may be the site of origin of various sarcomas. We review the various malignancies affecting this region of the body and attempt to put systemic treatment approaches into perspective. Material and methods: Non-systematic literature review. Results: Conventional types of osteosarcoma, Ewing sarcoma, and chondrosarcoma are the most frequent bone sarcomas occurring in craniofacial region, but variants may occur. The tumors' biologies and the resulting treatment strategies vary distinctly. As a general rule, local control remains paramount regardless of histology. The efficacy of antineoplastic chemotherapy varies by type of malignancy. It is clearly indicated in Ewing sarcoma and related tumors, potentially of benefit in high-grade osteosarcoma, undifferentiated pleomorphic sarcoma, dedifferentiated and mesenchymal chondrosarcoma, and of no proven benefit in the others. Conclusions: Various histologies demand various and distinct treatment approaches, with local control remaining paramount in all. The efficacy of systemic treatments varies by type of tumor. Prospective trials would help in all of these to better define systemic treatment strategies.