A snapshot of smokers after lung and colorectal cancer diagnosis

Background: Continued smoking after a cancer diagnosis may adversely affect treatment effectiveness, subsequent cancer risk, and survival. The prevalence of continued smoking after cancer diagnosis is understudied.

Methods: In the multi-regional Cancer Care Outcomes Research and Surveillance cohort (lung cancer [N = 2456], colorectal cancer [N = 3063]), the authors examined smoking rates at diagnosis and 5 months after diagnosis and also study factors associated with continued smoking.

Results: Overall, 90.2% of patients with lung cancer and 54.8% of patients with colorectal cancer reported ever smoking. At diagnosis, 38.7% of patients with lung cancer and 13.7% of patients with colorectal cancer were smoking; whereas, 5 months after diagnosis, 14.2% of patients with lung cancer and 9.0% of patients with colorectal cancer were smoking. Factors that were associated independently with continued smoking among patients with nonmetastatic lung cancer were coverage by Medicare, other public/unspecified insurance, not receiving chemotherapy, not undergoing surgery, prior cardiovascular disease, lower body mass index, lower emotional support, and higher daily ever-smoking rates (all P < .05). Factors that were associated independently with continued smoking among patients with nonmetastatic colorectal cancer were male sex, high school education, being uninsured, not undergoing surgery, and higher daily ever-smoking rates (all P < .05).

Conclusions: After diagnosis, a substantial minority of patients with lung and colorectal cancers continued smoking. Patients with lung cancer had higher rates of smoking at diagnosis and after diagnosis; whereas patients with colorectal cancer were less likely to quit smoking after diagnosis. Factors that were associated with continued smoking differed between lung and colorectal cancer patients. Future smoking-cessation efforts should examine differences by cancer type, particularly when comparing cancers for which smoking is a well established risk factor versus cancers for which it is not.