The cigarette burden (measured by the number of pack-years smoked) negatively impacts the response rate to platinum-based chemotherapy in lung cancer patients

Abstract

To evaluate the impact of the cigarette burden (CB) on the response rate to platinum-based chemotherapy (CT) in patients with lung cancer (LC). Retrospective study of patients with LC treated by CT from 2000 to 2005, in a tertiary referral center in Brazil. The CB was measured by the number of pack-years smoked (PY). To evaluate the response (by RECIST), it was necessary to accomplish two cycles of CT. The relevant variables were studied by univariate and multivariate statistical techniques. Two hundred and eighty-five patients (203 men) were studied (mean age=60.6+/-10.1 years, mean PY=58.3+/-35.4). 62.8% were current smokers, 26.7% were former smokers, and 10.5% were non-smokers. 63.2% had non-small-cell lung cancer (NSCLC), and 36.8% had small-cell lung cancer (SCLC). The treatment intent was palliative in 63.9% and curative in 36.1%. All 285 patients received platinum-based CT (etoposide/cisplatin in 68.8% and etoposide/carboplatin in 31.2%). Of these, 155 patients (54.4%) received RT (median dose=50.0 Gy; range=45.0-80.0). The 94 patients (33.0%) who responded to treatment had a mean PY of 38.7+/-27.1, and the 191 patients (67.0%) who did not respond had a mean PY of 67.8+/-35.1, p<0.001. In the multivariate analysis, the main independent negative predictor was CB>or=40 PY (adjusted OR=10.42; 95% CI=5.13-21.28). The others independent negative predictors were: CT (no. of cycles=2-4) (adjusted OR=4.86; 95% CI=2.44-9.68), treatment regimen with CT alone (adjusted OR=3.38; 95% CI=1.67-6.84), and NSCLC histology (adjusted OR=2.75; 95% CI=1.12-6.76). Patients with CB>or=40 PY have a worse response to platinum-based CT compared to those who have a CB<40 PY.