Smoking harms nearly every organ in the body and causes many diseases. Credit: CDC/Debora Cartagena

The largest study of its kind to date finds smokers diagnosed with cancer were more likely to quit than other smokers, supporting the hypothesis that a cancer diagnosis is a "teachable moment" that can be used to promote cessation. The study by American Cancer Society researchers appears early online in the Journal of Clinical Oncology.

Smoking increases the risk of second primary smoking-associated cancers; has been associated with poorer response to and ; and has many other than cancer. Among the estimated 13.7 million alive in the United States, the prevalence of smoking is estimated to vary between 15% and 33% depending on the type of cancer, age, and time since diagnosis.

Recent research has raised the idea that receiving a can be a "teachable moment" for smokers; an important opportunity to discuss smoking and provide cessation treatment. But relatively few studies have compared rates of smoking cessation between individuals with and without a recent cancer diagnosis.

For the current study, researchers led by J. Lee Westmaas, PhD of the American Cancer Society analyzed data over 17 years from more than 12,000 smokers enrolled in the Cancer Prevention Study (CPS)-II Nutrition Cohort.

The study found that smokers diagnosed with cancer were more likely to quit smoking within two years than smokers who did not receive a cancer diagnosis (31.3% vs. 19.0%). The same was true over a longer period, with smokers who received a cancer diagnosis having a higher quit rate within four years than other smokers (43.0% vs. 33.9%). The link between a recent cancer diagnosis and higher quit rates was seen in both sexes, but was more pronounced in women. The study included only cancer diagnoses that were not likely to be immediately life-threatening or to cause physical symptoms that would discourage smoking, making it less likely that physical symptoms of cancer caused smokers to quit. Results therefore suggest that a cancer diagnosis may have motivated some smokers to quit in order to lower their future disease risk.

"This is the first study to our knowledge to show that a cancer diagnosis, even for cancers not strongly related to smoking, can lead to higher quit rates," said Dr. Westmaas. "It appears a cancer diagnosis acts as a sort of 'cue-to-action' that leads smokers to quit."

While previous research has shown that oncologists do ask newly diagnosed lung cancer patients about quitting, actual follow up of patients' smoking status, including cessation assistance, is low. "Our study shows doctors can capitalize on this potentially teachable moment by discussing options for cessation treatment, by affirming the benefits of quitting, and by providing resources for follow-up tracking and support, even for non-smoking-related cancers" said Dr. Westmaas.

More information: Westmaas JL, Newton CC, Stevens VL, Flanders WD, Gapstur SM, Jacobs EJ: Does a recent cancer diagnosis predict smoking cessation? An analysis from a large prospective US cohort. J Clin Oncol [epub ahead of print on April 20, 2015] DOI: 10.1200/JCO.2014.58.3088

Journal information: Journal of Clinical Oncology