Smoking may increase risk of prostate cancer recurrence, death

A new study from Harvard School of Public Health (HSPH) and University of California, San Francisco, researchers suggests that men with prostate cancer who smoke increase their risk of prostate cancer recurrence and of dying from the disease. A link also was found between smoking at the time of prostate cancer diagnosis and aggressive prostate cancer, overall mortality (death) and cardiovascular disease mortality. "In our study, we found similar results for both prostate cancer recurrence and prostate cancer mortality," said Stacey Kenfield, lead author of the study and a research associate in the HSPH Department of Epidemiology. "These data taken together provide further support that smoking may increase risk of prostate cancer progression."

The study was published in the June 22-29, 2011, Journal of the American Medical Association (JAMA). It is the largest study to date to look at the relation between smoking at the time of prostate cancer diagnosis and prostate cancer-specific mortality and recurrence.

Kenfield and her colleagues conducted a prospective observational study of 5,366 men diagnosed with prostate cancer between 1986 and 2006 in the Health Professionals Follow-Up Study. The researchers documented 1,630 deaths, 524 (32%) due to prostate cancer, 416 (26%) due to cardiovascular disease, and 878 prostate cancer recurrences.

The researchers found that men with prostate cancer who were current smokers had a 61% increased risk of dying from prostate cancer, and a 61% higher risk of recurrence compared with men who never smoked. Smoking was associated with a more aggressive disease at diagnosis, defined as a higher clinical stage or Gleason grade (a measure of prostate cancer severity). However, among men with non-metastatic disease at diagnosis, current smokers had an 80% increased risk of dying from prostate cancer.

Compared with current smokers, men with prostate cancer who had quit smoking for 10 or more years, or who had quit for less than 10 years but smoked less than 20 pack-years before diagnosis, had prostate cancer mortality risk similar to men who had never smoked. Men who had quit smoking for less than 10 years and had smoked 20 or more pack-years had risks similar to current smokers.

"These data are exciting because there are few known ways for a man to reduce his risk of dying from prostate cancer," said senior author Edward Giovannucci, professor of nutrition and epidemiology at HSPH. "For smokers, quitting can impact their risk of dying from prostate cancer. This is another reason to not smoke."

Prostate cancer is the most frequently diagnosed form of cancer diagnosed in the United States and the second leading cause of cancer death among U.S. men, affecting one in six men during their lifetime. More than 2 million men in the U.S. and 16 million men worldwide are prostate cancer survivors.

Source: Harvard School of Public Health