Wedge resection margin distances and residual adenocarcinoma in lobectomy specimens

We studied 31 T1 N0 M0 peripheral adenocarcinomas diagnosed by wedge resection and treated by lobectomy. Factors recorded were pleural surface-based, gross cut-surface, and microscopic margin distances; morphologic features of the adenocarcinomas; microscopic extension distance of beyond gross perimeter of neoplasm; and presence of residual adenocarcinoma in the lobectomy specimen. All staple-line margins in the wedge and lobectomy specimens underwent complete histologic examination. The mean pleural surface-based, gross cut-surface, and microscopic margin distances in wedge resections were 13.1, 4.1, and 2.3 mm, respectively. The mean microscopic wedge resection margin distance was 11 mm smaller than the pleural surface-based measured margin. The mean microscopic lepidic growth beyond the gross perimeter of the neoplasm was 7.4 mm. Fourteen lobectomy specimens (45%) included adenocarcinoma. The mean microscopic wedge resection specimen margin distances in cases with and without residual adenocarcinoma in the lobectomy specimens were 0.7 and 2.4 mm, respectively (P < .001). Incomplete excision may contribute to higher locoregional recurrence rates following limited resection surgery. Two processes affected wedge resection margin distances: stapling-induced parenchymal stretching, resulting in overestimation of pleural surface-based distances, and microscopic extension of adenocarcinoma beyond the gross perimeter of the neoplasm.