In younger men with prostate cancer, those who are current or former smokers are more likely to have cancer that has spread outside of the prostate, according to a recent study.

William Roberts, MD, and colleagues from Johns Hopkins University in Baltimore, Md., found that among men under age 55, those with a history of smoking were at greater risk of having cancer that had spread beyond the prostate. The risk for current smokers was even higher than that for former smokers.

The researchers reported their results in the Journal of Urology (Vol. 169: 512-516).

Most large studies have not found a link between smoking and prostate cancer incidence. That is, men who smoke do not appear to be more likely to develop prostate cancer.

But some studies have suggested that men who smoke may be more likely to die of prostate cancer. Researchers aren’t sure why such a discrepancy may exist.

One possible explanation, according to the study authors, is that substances in cigarette smoke may act as cancer promoters. They may not cause the cancer itself, but they may affect the cancerous cells’ DNA in a way that makes them grow more quickly.

The researchers set out to try to determine if such a link might exist. They collected data on the smoking histories of more than 350 men who had undergone surgery for prostate cancer during the 1990s.

All of the operations had been done by Patrick Walsh, MD, and all of the men in the study were under 55 at the time of the surgery. This allowed the researchers to study a group with similar characteristics and without many other health problems.

Men who had ever smoked were 66% more likely to have had the cancer spread outside of the prostate by the time of surgery, when compared to those who never smoked. Those who had smoked within the last 10 years had a risk increased by more than two and a half times, while the risk for those who were still smoking was more than three and a half times higher.

The risk of having more advanced disease was also related to the amount smoked. This risk was highest among those with a history of at least 40 "pack-years" (for example, someone who smoked a pack a day for 40 years, or two packs a day for 20 years).

“These data support the theory that carcinogens in cigarette smoke may act as promoters of prostate cancer,” the researchers concluded.

But the news may not be all bad, if men can use the findings to their advantage. Men who quit smoking now, before they are diagnosed with prostate cancer, may improve their chances of having a more curable form of the disease if it arises later on.

Of course, this is only one of the many potential health benefits of quitting smoking. Tobacco use is thought to cause about 30% of all cancer deaths and a total of 440,000 premature deaths in the US each year.