Recurrence Dynamics After Complete Resection and Adjuvant Chemotherapy in Patients With Stage IIIA-N2 Non-Small Cell Lung Cancer

Abstract

To investigate the timing and pattern of recurrence in stage IIIA-N2 non-small cell lung cancer (NSCLC) patients after complete resection and adjuvant chemotherapy.The study cohort included pathologically confirmed stage IIIA-N2 NSCLC patients treated with complete resection and adjuvant chemotherapy from 2003 to 2015 in our single institution. Recurrence was categorized as local-regional recurrence (LRR), distant metastasis (DM) and both LRR and DM. The risk distribution was assessed by using clinical and pathological factors. The hazard rate function and competing risk analysis were used to evaluate the recurrence dynamics. The Gray's test was employed to estimate the cumulative recurrence rates and compare the differences between groups.Among 854 patients, 61.9% had multiple station N2 involvement. The 1, 3 and 5-year cumulative incidence rates of recurrence was 16.85%, 50.74% and 67.37%, respectively. Of the 510 patients who experienced recurrence, 95 (18.6%) experienced LRR, 285 (55.9%) experienced DM, whereas 130 (25.5%) had both LRR and DM. The hazard rate function for overall recurrence revealed a continuous increase between 0-18 months after surgery, consistent high level during 8-48 months and marked decline thereafter. And the DM displayed a hazard rate curve similar to that of overall recurrence. However, a double-peaked pattern of hazard rate was present in LRR and both LRR and DM. What's more, the peak recurrence frequency of DM differed by organs. A comparison of clinical and pathological factors revealed that patients with lower pT stage, single pN2 station and postoperative radiotherapy had a lower recurrence risk but similar pattern of recurrence.The recurrence risk of IIIA-N2 NSCLC after complete resection and adjuvant chemotherapy increased to a high level in 18 months and maintained continuously high till 48 months after surgery, which hinted necessity of intensive follow-up during this period of time. This follow-up strategy implied an individualized surveillance for N2 disease which was different from clinical routine, and should be verified in further studies.