MedWire News: US researchers report that a "significant minority" of patients diagnosed with lung or colorectal cancer are still smoking 5 months after they received their diagnosis.
"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," observe Elyse Park (Massachusetts General Hospital, Boston) and colleagues in Cancer.
The researchers examined the smoking behaviors of patients with lung cancer (n=2456) and colorectal cancer (n=3063) at the time of diagnosis and during follow up to better understand the extent and nature of the problem.
They chose to look at these two cancers because smoking is known to be a strong risk factor for lung cancer, whereas the smoking-attributable risk for colorectal cancer is unclear, and this difference in risk may result in different attitudes to smoking post diagnosis.
Study participants, who were aged 21 years and older, were asked about their smoking habits in a telephone interview shortly after diagnosis and then again 5 months later.
Overall, 90.2% of patients with lung cancer and 54.8% of patients with colorectal cancer reported ever smoking. By comparison, the rate in the general population is estimated to be around 42%, the researchers note.
At diagnosis, 38.7% of patients with lung cancer and 13.7% of patients with colorectal cancer were smoking. Five months later the smoking rates had fallen to 14.2% in patients with lung cancer and 9.0% in patients with colorectal cancer.
Therefore, significantly more patients with lung than with colorectal cancer who had been smoking around the time of diagnosis had quit by 5 months after diagnosis (63.0 vs 34.3%).
"Because of the widespread public knowledge that smoking causes lung cancer, it is plausible that patients with lung cancer associate their diagnosis with smoking and quit accordingly, whereas patients with colorectal cancer may not associate their diagnosis with smoking and, thus, may be less likely to change their smoking behavior as a result of their diagnosis," Park and co-authors remark.
"Another possibility is that oncology providers are more likely to talk to patients with lung cancer about quitting."
Multivariate analysis, restricted to patients with early-stage (stages I-III) cancer, showed that factors associated with continued smoking differed between lung and colorectal cancer patients.
Coverage by Medicare or other public/unspecified insurance (vs private insurance), not receiving chemotherapy, not undergoing surgery, prior cardiovascular disease, lower body mass index, lower emotional support, and higher daily ever-smoking rate were significantly and independently associated with continued smoking among patients with nonmetastatic lung cancer.
And, male gender, high school education, being uninsured, not undergoing surgery, and higher daily ever-smoking rates were associated with continued smoking among patients with nonmetastatic colorectal cancer.
These findings indicate that "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," say the researchers.
In an accompanying editorial, Carolyn Dresler (Arkansas Department of Health, Little Rock, USA) says that the research "highlights how critical it is for oncologists to address tobacco cessation with their patients - at the time of diagnosis."
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