e23502 Background: Osteosarcoma is the most common malignant bone tumor in adolescents, young adults and older adults. Current treatment management involves chemotherapy and surgical resection. However, pelvic osteosarcoma poorly responds to neoadjuvant chemotherapy and is difficult to obtain surgical margins due to pelvic anatomy, necessitating a hemipelvectomy. Studies addressing pelvic osteosarcoma surgical treatment modalities remain limited and necessary to characterize survival and clinical outcomes. Methods: This retrospective cohort study utilized the National Cancer Database (NCDB) to identify patients with osteosarcoma diagnosed between 2004-2021. Osteosarcoma of the pelvis was identified using International Classification of Diseases for Oncology (ICD-O-3), histology code 9180–9195 and primary site code C41.4. Only patients with osteosarcoma as their sole primary malignancy were included. Those with missing survival data, negative follow-up time or non-surgical management were excluded. Chi-square testing, Kaplan–Meier analysis, and Cox regression were performed on this sample, and statistical significance was defined as p < 0.05. Results: A total of 377 individuals were included. Patients who underwent pelvic amputation had worse 5-year survival than radical excision (mean survival 92.3 vs 124.5 months, p<0.001). Patients with positive surgical margins (HR 8.415, 95% CI 2.238–31.649, p=0.002), NCDB Stage IV (HR 10.550, CI 1.498–74.289, p=0.018), and increasing age (HR 1.097, 95% CI 1.035-1.163, p=0.002) were independently associated with worse survival. Patients who received radiation therapy (HR 0.140, 95% CI 0.027–0.724, p=0.019) and later year of diagnosis (HR 0.878, 95% CI 0.783–0.986, p=0.028) were associated with improved survival. Surgical procedure type was not an independent predictor of survival (HR: 0.478, 95% CI: 0.190–1.212, p=0.118). Patients who underwent pelvic amputation frequently had poorly differentiated tumors, NCDB stage II-IV, tumor size of 100 to <150 mm, received chemotherapy and on medicare and medicaid. Patients who underwent radical excision tended to have well or moderately differentiated tumors, NCDB stage I, tumor size of 50 to <100 mm, and have private insurance. Conclusions: Patients who underwent radical excision experienced better survival compared with pelvic amputation. However, when adjusting for clinical and tumor-related factors, surgical procedure type was not an independent predictor of survival, suggesting that outcomes are largely driven by underlying tumor biology and disease burden. Positive surgical margins, advanced NCDB stage, and increasing age were independently associated with worse survival, whereas patients who received radiation therapy and more recent year of diagnosis were associated with improved outcomes. Further studies should focus on anatomic extent, margin optimization and functional outcomes to guide surgical decision-making.
Respicio et al. (Thu,) studied this question.