Immunochemotherapy as induction treatment in Stage III (N2, N3) Non-small cell lung cancer

Abstract Background To increase locoregional and systemic tumor control, a portion of patients with stage III (N2, N3) non-small cell lung cancer (NSCLC) received pulmonary resection after immunochemotherapy in our center. Herein, we assessed the real-world downstage (T, N stage) effectiveness of immunochemotherapy as induction treatment and explored the proper cycle number for stage III (N2, N3) NSCLC. Methods Biopsy confirmed stage III (N2, N3) NSCLC patients who underwent immunochemotherapy between January 1st, 2018, to August 30th, 2019, were identified. Tumor radiologic regression, lymph node down-staging, and pathological response information were collected. Results In total, 16 patients with stage IIIA NSCLC, 30 with stage IIIB NSCLC, 9 with stage IIIC NSCLC (N2, N3 metastasis) were included. After immunochemotherapy, 25/55 (45.5%) patients achieved an objective response. Ultimately, 33/55 (60.0%) patients received lobectomy plus systemic lymphadenectomy, of whom 18/33 (54.5%) obtained major pathological response (MPR) of the primary lesion, and 24 (72.7%) had pathological-confirmed lymph node downstage (N2-3 to N0-1). Notably, four patients had MPR of the primary lesion but without lymph node downstage. At the time of data cutoff (December 30th, 2020), the median follow-up duration was 9.2 months (IQR 8.0-11.7), 24/33 (72.7%) of patients that had pulmonary resection were progression-free, with 30 of them alive. Binary logistics analysis showed that 3-4 induction cycles were favorably associated with MPR than 1-2 cycles (p = 0.017). Conclusions Immunochemotherapy as induction treatment showed encouraging MPR and lymph nodes down-staging rates in stage III (N2, N3) NSCLC in this study. Prolonged (3-4) cycles of immunochemotherapy were recommended for a better pathological response.