Cancer survivors who quit smoking have 36% less cardiovascular risk

These are the conclusions of an investigation published on World No Tobacco Day in the European Heart Journal.

According to the World Health Organization, there were more than 50.5 million cancer survivors worldwide in 2020.

The author of the study, Dr. Hyeok-Hee Lee, Faculty of Medicine, Yonsei University, Seoul, Korea, said: “A cancer diagnosis is an extremely stressful life event, which often leads to significant changes in a person’s lifestyle. in particular, it is a health-related behavior that can be strongly influenced by mental distress. However, little was known about the relationship between changes in smoking habits after a cancer diagnosis and the risk of cardiovascular disease – the leading cause of death unrelated to cancer among survivors of the condition.”

The researchers analyzed data from a Korean national health database. The study included 309,095 cancer survivors who had never had a heart attack or stroke. The median age was 59 years and 52% were women.

Participants underwent health screenings before and after their cancer diagnosis, during which smoking was assessed using a self-reported questionnaire. Patients were divided into four groups based on their change in smoking habits after receiving a cancer diagnosis: (1) sustained non-smokers, (2) quitters, (3) new/relapsers, and (4) continuous smokers.

Of the 309,095 cancer survivors, 250,102 (80.9%) continued to not smoke, 31,121 (10.1%) stopped smoking, 4,777 (1.5%) started or resumed smoking, and 23,095 (7.5%) continued to smoke after being diagnosed with cancer. The proportion of new, relapsed, and continued smokers combined was highest among urinary tract cancer survivors and lowest among breast cancer survivors.

The researchers assessed the risk of cardiovascular events (myocardial infarction, stroke, or death due to cardiovascular disease) for each group over an average of 5.5 years. Analyzes were adjusted for characteristics that could influence the association between smoking and cardiovascular events, including age, gender, household income, residential area, alcohol, physical activity, body mass index, blood pressure, blood glucose, cholesterol level, number of other medical conditions, medications, type of cancer, and anticancer treatments.

Compared with sustained non-smoking, the risk of cardiovascular events during follow-up was 86%, 51%, and 20% higher among continuous, new,/relapsed, and quitters, respectively. The results were consistent for women and men, and when the risk of myocardial infarction, stroke and cardiovascular death were analyzed separately.

The benefits of quitting were even greater when compared to continuing to smoke. Of those who were smokers before being diagnosed with cancer, 57% quit smoking after finding out they had cancer. Smoking cessation was associated with a 36% reduction in the risk of cardiovascular events compared with continued smoking.

Approximately one in five patients who continued to smoke reduced their daily tobacco use by at least 50% after being diagnosed with cancer. Patients who continued to smoke but smoked less after learning they had cancer had the same risk of cardiovascular events as those who continued to smoke without reduction.

“Some individuals may find solace in successfully reducing smoking without stopping completely,” said Dr. Lee. “However, our results imply that smoking less should not be the end goal and that smokers should stop completely to gain the benefits of quitting entirely.”

Of those who were non-smokers before their cancer diagnosis, 2% started or resumed smoking after finding out they had cancer. Smoking initiation or relapse was associated with a 51% increase in the risk of cardiovascular disease compared with sustained non-smoking.

The Doctor. Lee said: “Although our study does not provide conclusive evidence for the underlying causes of smoking initiation or relapse, some cancer survivors may lose motivation to lead a healthy lifestyle after recovery, while others may turn to smoking as a way to of dealing with the stress of his diagnosis. These are only speculations, and more research is needed to determine factors associated with smoking initiation or relapse in cancer survivors.”

He concluded: “Our results reinforce existing evidence on the known cardiovascular risks of smoking and emphasize the benefits of smoking cessation, even for cancer survivors. Furthermore, the finding that more than 40% of patients who smoked before their cancer diagnosis continued to smoke afterwards, highlights the need for more robust efforts to promote smoking cessation among cancer survivors, who are already at an elevated risk. of cardiovascular disease”.

Source: European Society of Cardiology