P2.17-23 Optimal Therapy of Stage III NSCLC: The Role of Surgery in the Era of Immunotherapy

Abstract

Curative intent treatment of stage III NSCLC may include surgery, radiotherapy, chemotherapy, or combination therapy. Management is influenced by both patient and disease characteristics. N2 disease is optimally treated with concurrent chemoradiotherapy (CRT) and the role of surgery after CRT remains a subject of debate. The recent PACIFIC study of adjuvant durvalumab after CRT in stage III showed unprecedented improvements in relapse free survival, which further calls into question the role of surgery. We sought to perform a real-world analysis of curative therapies in stage III NSCLC, and explore the impact of known prognostic factors on outcome. A retrospective review was completed of all patients referred to BC Cancer from 2005-2012 with stage III NSCLC treated with curative intent including surgery, radiotherapy, chemoradiotherapy, and combined surgery and radiation +/- chemotherapy (S+RT+/-C). Information was collected on known prognostic factors. The primary outcome measure was overall survival. 688 patients were included in the study. Baseline characteristics: female 47%, median age 65, ECOG 0-1 65%, weight loss <5% 74%, stage IIIA/IIIB 73%/27%. Treatment: 82 (12%) surgery, 127 (18%) radiotherapy, 423 (62%) chemoradiotherapy, and 56 (8%) combined S+RT+/-C. Median overall survival: surgery 28.6m, chemoradiotherapy 27.6m, radiotherapy alone 18.0m, and S+RT+/-C 55.9m. In a multivariate model incorporating age, sex, weight loss, ECOG, and stage, the survival difference disappeared between the surgery, chemoradiotherapy, and radiotherapy cohorts and persisted in the S+RT+/-C cohort. In stage III NSCLC, the performance of surgery, chemoradiotherapy and radiotherapy alone are comparable after controlling for known prognostic factors. Combined S+RT+/-C appears to provide a significant benefit above other modalities in highly selected patients. The role of surgery post-CRT remains controversial, as immunotherapy demonstrates greater promise for improving outcomes for the diverse group of stage III NSCLC.