Physical activity linked to lower death risk in men with localized prostate cancer

Around 1 in 7 men will develop prostate cancer in their lifetime. But a new study suggests men with localized prostate cancer could reduce their risk of all-cause and prostate cancer-specific mortality simply by exercising more.

Walking or cycling for 20 minutes a day or more was found to lower the risk of death for men with localized prostate cancer.

The researchers at the Department of Medical Epidemiology and Biostatistics at the Karolinska Institutet in Sweden - publish their findings in the journal Cancer Epidemiology, Biomarkers & Prevention.

According to the American Cancer Society, approximately 233,000 new cases of prostate cancer will have been diagnosed this year, and almost 30,000 men will have died from the disease.

Past studies have suggested that physical activity may reduce the risk of developing prostate cancer. But the research team says very few studies have investigated the effects of exercise following a prostate cancer diagnosis.

"The aim of this study," the researchers explain, "was to investigate the effect of physical activity after a prostate cancer diagnosis on both overall and prostate cancer-specific mortality in a large cohort."

Walking or cycling for 20 minutes a day or more reduced mortality by at least 30%

The team analyzed the data of 4,623 men who were a part of the National Prostate Cancer Register of Sweden Follow-up Study.

All men had been diagnosed with localized prostate cancer - cancer that has not spread outside the prostate - between 1997 and 2002, and they were monitored until 2012.

During the study, the men were required to complete questionnaires on their diet and lifestyle, and the researchers were able to determine the cause and date of death of any participants by analyzing information from the Swedish Cause-of-Death Register.

During the follow-up period, the team identified 561 deaths from all causes and 194 deaths from prostate cancer.

The results of the analysis revealed that men who walked or cycled for 20 minutes or more each day were 30% less likely to die from any cause and 39% less likely to die from prostate cancer, compared with men who walked or cycled less than 20 minutes a day.

What is more, the team found that men who engaged in physical activity for at least 1 hour a week were at 26% lower risk of all-cause mortality and 32% lower risk of prostate cancer-specific mortality, compared with those who exercised for less than 1 hour each week.

Commenting on the team's findings, the research team says:

"Our results extend the known benefits of physical activity to include prostate cancer-specific survival.

However, it is important to remember that our results are on a group level. An individual's survival depends on many factors, but physical activity is one factor that individuals can modify. Hopefully, our study can motivate men to be physically active even after a prostate cancer diagnosis."

The researchers note that because almost all men diagnosed with prostate cancer in Sweden between 1997 and 2002 were a part of the National Prostate Cancer Register of Sweden Follow-up Study, their results can be generalized to the entire population.

However, this data came only from men who were still alive in 2007, which most likely excludes men with more aggressive disease. Our results are, therefore, most applicable to men with less aggressive disease.

Last month, we reported on a study by researchers from the University of California-Davis, which suggested a diet rich in walnut or walnut oil could slow prostate cancer growth.

References:

1.  Physical activity and survival among men diagnosed with prostate cancer, Stephanie Bonn, et al., Cancer Epidemiology, Biomarkers and Prevention, doi: 10.1158/1055-9965.EPI-14-0707, published online 19 December 2014, abstract.
2.  American Association for Cancer Research news release, accessed 19 December 2014.
3.  Additional source: American Cancer Society prostate cancer statistics, accessed 19 December 2014.