Positive plasma cotinine during platinum-based chemotherapy is associated with poor response rate in advanced...

Patients with advanced non-small cell lung cancer (NSCLC) are most of the time treated with a first-line cytotoxic chemotherapy. Tobacco use is responsible for 90% of lung cancer. The aim of this study was to evaluate the impact of smoking continuation during first-line chemotherapy on tumor response in advanced-stage NSCLC.

All patients with an advanced-stage NSCLC (IIIb or IV), treated with first-line platinum-based chemotherapy in our Department between June 2013 and July 2017 were included. Smoking status was assessed at inclusion by self-report, then at the tumor assessment consultation after 2 months of treatment, by both self-report and plasmatic cotinine measurement. Chemotherapy response, progression-free survival (PFS), overall survival (OS) and stage 3-4 toxicity were registered.

Ninety-seven patients were included: 8 (8%) declared to be non-smokers, 56 (58%) current smokers and 33 (34%) former smokers at diagnosis. At the first tumor evaluation, 24 (25%) self-reported as active smokers and 73 (75%) as non-smokers; overall response rate (ORR) was respectively 38% and 48% (p = 0.373). Fifty-four patients had a plasmatic cotinine evaluation at the first tumor evaluation. Seventeen patients (32%) had a positive cotinine rate (median 108ng/mL, IQR 31-236). Six patients (35%) had positive cotinine rate whereas declaring to be non-smokers at the first tumor evaluation. ORR was 18% in case of positive cotinine rate, and 57% when negative (p = 0.007). Regardless of the method for smoking status evaluation, PFS, OS and grade 3-4 toxicities were similar between smoker and non-smoker patients at the first tumor evaluation.

Smoking continuation during platinum-based chemotherapy, reflected by positive plasma cotinine rate, was associated with a poor ORR.