Pulmonary Surgical Margins for Metastatic Osteosarcoma: Is Negative Margin Enough?

Background: In advanced osteosarcoma, the lung is the most frequent site of distant metastasis, with metastasectomy often used for local disease control. The influence of pulmonary resection margin length on outcomes for osteosarcoma has not been well explored. This study sought to evaluate the impact of margin length relative to tumor size on local recurrence and survival in lung-limited metastatic osteosarcoma.

Methods: Patients with metastatic osteosarcoma who underwent lung resection between 2000 and 2020 were identified from a single institution. Clinicopathologic variables were collected. The margin length-to-tumor size ratio (MTR) was calculated per nodule and classified relative to an MTR of 0.5. The primary outcome was development of local recurrence per nodule. Multivariate logistic regression was used to investigate covariates.

Results: A total of 142 patients with 689 nodules met inclusion criteria, with mean age of 35.6 years (interquartile range [IQR], 20.9-46.6 years). Patients were predominantly male (n = 87; 61.3%) and White (n = 106; 72.5%). Most nodules (n = 644; 93.5%) were resected through thoracotomy. The mean tumor size was 0.8 cm (IQR, 0.5-1.70 cm), with an average margin length of 0.3 cm (IQR, 0.1-0.7 cm). Among all nodules, 299 (43.4%) had an MTR >0.5. Systemic therapy was received by 94 patients (66.2%) preoperatively and by 100 patients (70.4%) postoperatively. Importantly, the study found that an MTR >0.5 conferred a protective effect against disease recurrence (hazard ratio, 0.67; 95% CI, 0.52-0.87; P = .003).

Conclusions: In resected pulmonary metastatic osteosarcoma, a margin length greater than one-half the size of the pulmonary nodule is associated with a lower incidence of local disease recurrence. This finding has implications for the subsequent need for additional therapy and disease-free status, thus meriting attentive intraoperative consideration.