Risk of CVD Events in Cancer Survivors Affected by Smoking Patterns After Diagnosis

Patterns of smoking habits following a cancer diagnosis indicate many survivors continue to smoke, and some resume smoking, despite the reduction in risks of cardiovascular disease (CVD) events associated with quitting. These study findings were reported in the European Heart Journal.

“[More than] 40% of smokers in our study opted to continue smoking even after [a] cancer diagnosis,” the study investigators wrote in their report.

The study was based on records from a nationwide database of the Korean National Health Insurance Service. Study participants were adults identified in this database who were at least 20 years old and who received a new cancer diagnosis between 2006 and 2013.

The investigators evaluated self-reported questionnaires regarding smoking status among study participants during the last examination within 2 years before diagnosis and the last examination within 3 years after diagnosis. The primary study outcome was a composite CVD event, defined as initial hospitalization for myocardial infarction or stroke, or cardiovascular death. Outcomes related to CVD and the cumulative incidence of CVD events were also evaluated.

A total of 309,095 cancer survivors (median age, 59 years) were included in the analysis. Following their cancer diagnoses, 80.9% reportedly sustained nonsmoking status, 10.1% had quit smoking, 1.5% began or resumed smoking, and 7.5% continued smoking after their cancer diagnoses.

These smoking-related patterns varied across types of cancer. The combined rate of patients initiating/relapsing or continuing smoking was lowest among breast cancer survivors (1.0%) and highest for survivors of urinary tract cancers (15.6%). This rate was 6.5% for lung cancer survivors.

Within a median follow-up time of 5.5 years, 10,255 new CVD events were identified among the study participants. Multivariable analysis showed the cumulative incidence of CVD events was the lowest among sustained nonsmokers.

Relative to sustained nonsmokers, participants who had continued smoking had the greatest cumulative incidence of CVD events (adjusted hazard ratio [HR], 1.86; 95% CI, 1.74-1.98). Participants who quit smoking had the second-lowest cumulative incidence (adjusted HR, 1.20; 95% CI, 1.12-1.28), and smoking initiators/relapsers had the second-highest cumulative incidence of CVD events (adjusted HR, 1.51; 95% CI, 1.33-1.71).

Relative to continuing smokers, multivariable-adjusted HR for CVD events was 0.64 (95% CI, 0.59-0.70) for quitters.

There were also 15,392 continuing smokers for whom data were available on tobacco consumption per day. Among these participants, 20.2% had reduced their daily tobacco intake after their cancer diagnosis by at least 50%. However, smoking reduction was not associated with a lower risk of CVD events (HR, 0.99; 95% CI, 0.80-1.22).

“As cancer survivors can gradually lose their motivation for maintaining a healthy lifestyle after recovery, tobacco prevention support for nonsmoking survivors should continue throughout the whole survivorship phase,” the study investigators wrote in their report.

Disclosures: Some authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

Reference

Lee HH, Lee H, Bhatt DL, et al. Smoking habit change after cancer diagnosis: effect on cardiovascular risk. Eur Heart J. Published online June 1, 2023. doi:10.1093/eurheartj/ehad199