Surgical resection of the primary lesion for osteosarcoma patients with metastasis at initial diagnosis

Background: Approximately 10-20% of osteosarcoma patients present with metastasis on diagnosis. Completely resecting the lesion is associated with better prognosis. However, evidence regarding optimal surgical strategies for patients with unresectable metastasis is limited.

Methods: This retrospective analysis was based on the Japanese Nationwide Bone and Soft Tissue Tumor registry. In total, 335 patients diagnosed with osteosarcoma with metastasis were included. Factors affecting overall survival were identified using multivariate analysis. Kaplan-Meier method was used to compare the overall survival by the status of surgical intervention. Two hundred and four patients who did not undergo surgery for metastasis were divided into two groups, depending on whether they underwent surgery for the primary lesion. The background differences between these two groups were adjusted with propensity score matching, with 43 patients per group. The overall survival was calculated using the Kaplan-Meier method and compared with a log-rank test.

Results: Factors positively impacting overall survival were age <40, female sex, extremity origin, surgery for the primary lesions, surgery for metastasis and radiotherapy without surgery. For patients with unresectable metastasis, after propensity score matching, the survival rate was higher in the group that underwent primary lesion surgery than the group without surgery. Their median survival was 19 (95% confidence interval: 11.7-26.3) and 11 months (95% confidence interval: 4.5-17.5) (P = 0.02), respectively.

Conclusions: Surgical resection of the primary osteosarcoma lesion did not worsen prognosis, even in patients with unresectable metastasis. Further study is needed to identify which patient group will benefit from primary lesion resection.