Prognostic significance of pathological complete response in non-small cell lung cancer following neoadjuvant treatment.

Background: This study aims to investigate the factors associated with pathological complete response following neoadjuvant treatment and to examine the prognostic value of pathological complete response in patients with non-small cell lung cancer undergoing surgical resection.

Methods: Between February 2009 and January 2016, a total of 112 patients (96 males, 16 females; mean age 60±8 years; range, 37 to 85 years) with the diagnosis of non-small cell lung cancer who underwent anatomical pulmonary resection after neoadjuvant treatment were retrospectively analyzed. Demographic, clinical, radiological, and pathological characteristics of the patients were recorded. The patients were classified as pathological complete response and nonpathological complete response according to the presence of tumors in the pathology reports. Predictive factors for pathological complete response and its prognostic significance were analyzed.

Results: The mean follow-up was 35±20 (range, 0 to 110) months. Of the patients, 30 (27%) achieved a pathological complete response. Reduction rate in tumor size was significantly higher in the responsive group (32.5±21.6% vs. 19.2±18.8%, respectively) and was a predictor of pathological complete response independent from the T and N factors (p=0.004). Survival of the responsive patients was significantly longer than unresponsive patients (75±9 vs. 30±4 months, respectively; p<0.001). During follow-up, tumor recurrence was seen in 30 patients. Recurrence was observed in only one patient in the responsive group, while 29 patients in the unresponsive group had recurrence or metastasis.

Conclusion: Tumor shrinkage rate after neoadjuvant treatment in non-small cell lung cancer is a predictive factor for pathological complete response. Survival of patients with a pathological complete response is also significantly longer than unresponsive patients.