January 01, 2017
Here’s another reason not to smoke, and for men it’s a big one: If you smoke, you are more likely to develop aggressive prostate cancer, and to die from it. If you already have prostate cancer and you continue to smoke after your treatment, the prostate cancer is more likely to come back, and you are more likely to die from it.
The good news is that if you stop smoking, your risk of dying of prostate cancer returns to that of someone who has never smoked.
In exciting work, epidemiologists Miranda Jones, Ph.D., Corinne Joshu, M.P.H., Ph.D., and Elizabeth Platz, Sc.D., M.P.H., have shown this on a large scale. “We knew what was happening in our cohort studies of men who smoked, quit smoking, or never smoked,” says Platz. The team wondered, might there be a similar drop in prostate cancer deaths in entire states where the prevalence of smoking has gone down?
It took 50 years — from 1964, when the first U.S. Surgeon General’s report on Smoking and Health blamed cigarette smoking as a cause of many cancers, to 2014 — before the U.S. Surgeon General officially concluded that smoking also raises the risk of death from prostate cancer. And it has taken years of policy changes — carrot-and-stick strategies such as cigarette taxes, workplace smoking bans, indoor air pollution laws, and offering free or low-cost services to help people stop smoking — but they have worked. Several states “have significantly lowered the number of people who smoke,” Platz says. They looked at four states where the number of smokers has changed significantly: California, Kentucky, Maryland, and Utah.
The team looked at prostate cancer death rates in these states between 1999 and 2010. “This was fully in the PSA era,” Platz notes, when screening for prostate cancer became more widespread. “We found that as the prevalence of smoking declined in these states, their prostate cancer death rates declined in parallel.” This work was published in Preventing Chronic Disease. How did they know that the drop in deaths was due to men quitting smoking, and not other reasons? They looked at other kinds of deaths, such as “accidents, homicides, and suicides, deaths from external causes that would not be related to smoking, and did not see this pattern,” Platz says. Also important: “these declines in smoking and prostate cancer mortality were evident in black and white men.” Next, in collaboration with investigators in the Atherosclerosis Risk in Communities study, the team looked at the health of more than 6,600 men, white and black, who started the study when their average age was between 54 and 55. They followed the men’s health from the late 1980s through 2012. They also took into account age, education, body mass index, height, and physical activity. Over an average of nearly 20 years, 84 of the men had died of prostate cancer. “Compared with men who had never smoked, men who were smoking cigarettes at the start of the study had almost twice the risk of dying of prostate cancer in the future,” says Platz. “Men who had quit smoking before the study started, and men who had occasionally smoked pipes or cigars did not have an increased risk of prostate cancer death. Looking more closely at the timing of smoking, men who continued to smoke cigarettes or who quit within 10 years had 1.85 times the risk of death from prostate cancer — but men who quit longer ago did not have an increased risk.” In other words, over time, if you quit smoking, your risk of dying of prostate cancer becomes that of a man who has never smoked. “These patterns were the same in both white and black men.”
Platz worries that the message to “quit smoking” has gotten stale; that we’ve all heard it so much, we tune it out. “But here is a potential strategy to reduce the number of prostate cancer deaths, including in black men — who suffer a disproportionate burden of prostate cancer.” About 17 percent of American men still smoke. “There is more help to quit smoking now than ever, and not dying of prostate cancer is a very good incentive to quit.”