原发性肋骨骨肉瘤并没有得到广泛的研究，而临床特征和最佳的治疗策略也没有明确定义。作者使用了合作骨肉瘤研究组（COSS）的数据库来对这种肿瘤深入分析。在COSS数据库中搜索了未经治疗的高级别肋骨骨肉瘤。分析了受影响患者的人口和肿瘤相关因素、治疗和结果。总共有44名患者（23名男性，21名女性；中位年龄23岁[范围6-59]）。在44名患者中，6名（14％）患者出现了原发性转移。在44名患者中，40名（91％）接受了手术治疗，35名（80％）患者的病灶被切除。43名患者（98％）知道接受过化疗，而7名42名（17％）接受了放疗（2名患者无数据）。仅有5名（33％）接受了术前化疗的15名评估患者良好的化疗反应。在所有患者的中位随访时间为2.49（0.22-40.35）年，26名幸存患中位随访时间为6.61（0.25-40.35）年（其中21名处于第一次完全缓解），5年总生存率和事件自由生存率分别为53.0％（8.5％）和42.2％（8.1％）。不完全切除肿瘤是最明显的负面预后因素。成骨组织学和化疗反应差等可能是其原因。这个大规模的研究表明，原发性肋骨骨肉瘤患者普遍比一般骨肉瘤患者年龄较大，但与其他部位的肿瘤一样，似乎具有相似的肿瘤生物学和预后因素，如果按照标准方案治疗，则其预后相对较好。早期术前诊断和永久性、切实有效的局部控制仍然是重大挑战，并应为改善预后做出贡献。©2023年美国癌症协会。

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.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.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.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.© 2023 American Cancer Society.