Maintaining a healthy lifestyle after cancer has a noticeably positive effect on life expectancy, according to a large prospective population-based cohort study of more than 6000 cancer survivors.

Researchers at the German Cancer Research Center (DKFZ) in Heidelberg, Germany, reported that adherence to key lifestyle recommendations remained strongly associated with lower mortality even years after diagnosis, with direct implications for clinicians’ approach to cancer survivorship care.

The findings, published in the European Journal of Epidemiology, showed that individuals who were diagnosed with cancer at least 5 years in the past and who did not smoke, exercised sufficiently, and maintained a healthy body weight lived on average significantly longer than other long-term cancer survivors with less healthy habits.

Speaking with Medscape’s German edition, Volker Arndt, PhD, head of the Cancer Survivorship Research Group at the DKFZ and director of the Epidemiological Cancer Registry of Baden-Württemberg, Heidelberg, Germany, said, “Many patients ask after completing treatment for cancer what they themselves can still do for their health. Our study provides an encouraging answer: lifestyle factors such as not smoking, sufficient physical activity, and a healthy body weight remain important even in the long term.”

Lifestyle Factors

The research team, led by the corresponding author Melissa Thong, PhD, analyzed data from 6057 individuals with a mean age of 69 years who had been diagnosed with breast, prostate, or colorectal cancer at least 5 years earlier. The mean interval between the initial diagnosis and the current diagnosis was 8 years. The study aimed to analyze the relationships between individual and combined factors of a healthy lifestyle and mortality in long-term cancer survivors.

Participants were enrolled in the CAESAR study, a multicenter population-based study initiated in 2008 across six German regions: Bremen, Hamburg, North Rhine-Westphalia, Rhineland-Palatinate, Saarland, and Schleswig-Holstein. Women comprised 52.1% of the study cohort.

Among the participants, 2654 had a history of breast cancer, 2186 had prostate cancer, and 1212 had colorectal cancer.

Between 2009 and 2011, participants completed questionnaires addressing four lifestyle factors: smoking behavior, alcohol consumption, body weight, and physical activity. Diet was not assessed.

Composite Score

Each lifestyle factor was scored according to adherence to the recommendations of the World Cancer Research Fund and the American Institute for Cancer Research. Full adherence was assigned to one-point, partial adherence to 0.5, and nonadherence to zero points, yielding a total possible score of 0-4.

Based on the total scores, the researchers categorized the participants into three groups:

• Participants scoring 3-4 points were classified as having a healthy lifestyle (42.5%)
• Participants scoring 2.5 points as intermediate (23.3%)
• Participants scoring 0-2 points indicated an unhealthy lifestyle (34.2%)

Vital status until the end of 2021 and dates of death were obtained from the participating cancer registries. The maximum follow-up period was 12.3 years. During the follow-up, deaths occurred in 2015 among cancer survivors.

Participants’ diets were not recorded in the survey, although the authors acknowledged that they contribute significantly to a healthy or unhealthy lifestyle. Future research should therefore investigate the impact of other lifestyle factors, such as diet, sleep quality, and sedentary behavior, as well as lifestyle changes, on prognosis and quality of life after a cancer diagnosis some time ago, the authors of the study noted.

“A particular strength of our study is the large number of long-term cancer survivors and the long follow-up period,” said Arndt. This allowed for a robust investigation of the relationship between lifestyle and mortality. “Unlike many previous studies, we don’t just look at individual factors in isolation, but at the interplay of several of them — which is much closer to reflecting individual’s lived experiences.”

Mortality Outcomes

Compared with participants with an unhealthy lifestyle, the mortality rate was 27% and 32% lower among those with an intermediate and healthy lifestyle, respectively.

The association between healthy behaviors and lower mortality rate was consistent across age and sex and independent of cancer type and the presence of other chronic conditions, including metabolic and cardiovascular diseases.

“A healthy lifestyle not only helps prevent cancer but can also make a substantial difference after a cancer diagnosis,” said Arndt.

Smoking status was the most strongly associated with survival. Individuals who had never smoked had 49% fewer deaths during follow-up than those who were current smokers. Those who quit smoking had a 29% lower mortality rate than current smokers.

Physical activity lowered mortality rate by 22% reduction when comparing the highest and lowest activity groups. Maintaining a healthy BMI was associated with a 13% reduction in mortality rate.

The findings on the effects of alcohol consumption were less consistent. Although low alcohol intake initially appeared to be beneficial, this association lost statistical significance after adjusting for other lifestyle factors. Arndt noted that, in clinical practice, the focus should be less on individual measures and more on the overall pattern of a healthy lifestyle.

“We were surprised by how consistent and clear the link between a healthy lifestyle and lower mortality was, even many years after a cancer diagnosis,” Arndt said. “This suggests that health promoting behavior remains relevant even at a stage of life when many may underestimate the influence of lifestyle.”

Survivorship Care

According to researchers, more than 5 million individuals in Germany live after a cancer diagnosis, and more than two thirds have survived for longer than 5 years. At the same time, most long-term survivors only partially meet or do not meet the recommendations for a healthy lifestyle.

Nonadherence was more common among men, individuals with lower levels of education, those without a stable partner, and those with comorbidities.

“Given the steadily growing number of cancer survivors, it is becoming increasingly important to think about follow-up care and prevention together,” said Arndt.

A healthy lifestyle can significantly improve the long-term health of this large population.

“However, it is important to emphasize that lifestyle is not a substitute for medical treatment, and no one should be held responsible for their illness,” Arndt said. “Rather, our results show that supportive measures in everyday life can help improve long-term health prospects.”

This story was translated from Medscape’s German edition.