Prognostic Impact of Histopathologic Response after Neoadjuvant Chemotherapy in Stage IIIA Non-small Cell Lung Cancer

Abstract

Objective: To investigate prognostic impact of histopathologic response induced by neoadjuvant chemotherapy in patients with stage IIIA non-small cell lung cancer (NSCLC). Methods: Forty patients with stage IIIA NSCLC underwent two cycles of neoadjuvant chemotherapy with mitomycin, vindosine, and cisplatin followed by surgery. Histopathologic response in resection of the tumor was examined after surgery. Tumor regression was classified as grade IV, grade III, grade II, and grade I according to the extent of tumor necrosis and the extent of the vital tumor tissues. The tumor regression grading was correlated with the survival time of the patients. Results: After two cycles of chemotherapy, 19 (47.5%) of 40 patients had objective response (2 complete and 17 partial response). In 40 resected tumor specimens, 2 (5%) were classified as regression grade IV, 16 (40%) as regression grade III, 18 (45%) as regression grade II, and 4 (10%) as regression grade I. The rate of complete surgical resection was significantly higher in patients with tumor regression grade III-IV (<10% vital tumor tissue)(P<0.05). The median survival time in patients classified as having tumor regression grade III-IV was significantly longer than that in patients who had regression grade I-II (P<0.05). The 3-year survival rate in patients with regression grade III-IV was markedly higher than that in patients who had regression grade I-II (P<0.05). Conclusion: The extent of tumor regression induced by neoadjuvant chemotherapy is a critical issue for successful therapeutic approach in patients with stage IIIA NSCLC. In resected specimens of tumors after chemotherapy, the presence of marked tumor regression (regression grade III-IV) is predictive for superior survival time.