Value of adjuvant chemotherapy in patients with resected stage IB solid predominant and solid non-predominant lung adenocarcinoma

Background The use of adjuvant chemotherapy (ACT) for stage IB lung adenocarcinoma remains controversial. We examined the benefits of ACT in stage IB patients with tumors composed of solid material. Methods The records of 309 patients with stage IB lung adenocarcinoma who had undergone complete resection between 2006 and 2015 were reviewed. All pathological slides were evaluated for the composition of solid material. Results Our data showed that although disease-free survival (DFS) and overall survival (OS) were not significantly different (P = 0.306 and P = 0.061, respectively) between patients displaying a solid pattern of tumor growth and treated with or without ACT, patients with a solid predominant pattern of tumor growth treated with ACT had longer DFS (hazard ratio 0.359; P = 0.033) and OS (hazard ratio 0.205; P = 0.003). In patients with solid non-predominant patterns, treatment with ACT had no effect on DFS (P = 0.326) or OS (P = 0.508). Conclusions Postoperative patients with the solid predominant pattern of stage IB lung adenocarcinoma may benefit from ACT, while those with the solid non-predominant pattern will not.