Impact of resection margin length and tumor depth on the local recurrence after thoracoscopic pulmonary wedge resection of a single colorectal metastasis.

Background: To evaluate the influence of tumor depth on preoperative computed tomography (CT) image, and resection margin length on local recurrence after pulmonary metastasectomy of colorectal cancer.

Methods: Patients undergoing thoracoscopic pulmonary wedge resection for single pulmonary metastasis of colorectal cancer origin from 2007 to 2017 were analyzed. Factors such as resection margin, tumor size and depth were analyzed. The local recurrences of two subgroups based on the pulmonary resection margin (Group 1: resection margin 1-10 mm or shorter than the tumor size, Group 2: resection margin >10 mm or at least greater than the tumor size) were analyzed.

Results: Sixty-five patients were included in this study. The local recurrence rate was 12/65 (18.5%). Median follow up period was 33 months. Median tumor size and depth on preoperative CT were 1.1 and 1.6 cm. Median length of resection margin was 0.5 cm (group 1: 0.4 cm, group 2: 1.0 cm, P<0.001). No difference was noted in 3-year local recurrence-free survival (80.8% 76.7%, P=0.756) between the two subgroups. No significant correlation was noted between the length of resection margin and the tumor size and depth. However, tumor depth was an independent factor related to higher local recurrence on multivariate analysis.

Conclusions: Extent of resection margin in pulmonary metastasectomy does not seem to affect significantly on the local recurrence if complete resection is accomplished. However, preoperative tumor depth on CT image and postoperative distant metastasis seem to affect on local recurrence after pulmonary metastasectomy.