Local failure after stereotactic body radiation therapy or wedge resection for colorectal pulmonary metastases

Objective Several options are available for the local treatment of colorectal pulmonary metastases; however, the efficacy of each treatment has not been well characterized. We compared the risk of local recurrence after wedge resection or stereotactic body radiation therapy for pulmonary metastases of colorectal origin. Methods We retrospectively reviewed records of patients treated for pulmonary colorectal metastases with stereotactic body radiation therapy or wedge resection from 2006 to 2016 at a single institution. Local recurrence was defined as an enlarging nodule either adjacent to the staple line or within the radiation field on computed tomography. Matching weights using the propensity score with death as a competing event was used to estimate the risk of local recurrence for each metastatic nodule. Results A total of 381 patients underwent 762 wedge resections and 64 courses of stereotactic body radiation therapy for definitive treatment of 826 pulmonary nodules. The risk of local recurrence was increased with stereotactic body radiation therapy (hazard ratio, 3.28; 95% confidence interval, 1.53-7.04; P = .002) and larger tumor size (hazard ratio, 1.38 per additional centimeter; 95% confidence interval, 1.01-1.87; P = .042). After reweighting with matching weights, the marginal 2-year risk of local recurrence for each nodule was 14.1% (95% confidence interval, 9.8-18.5) after wedge resection and 29.4% (95% confidence interval, 13.8-45.0) after stereotactic body radiation therapy (P = .023). Conclusions Pulmonary colorectal metastases treated with stereotactic body radiation therapy have a higher risk of local recurrence than those treated with wedge resection. Stereotactic body radiation therapy should be reserved for patients with comorbidities precluding surgical resection.