According to a large population-based study conducted by Lund University in Sweden, smokers are less likely to get prostate cancer, but more likely to die from the disease.
Researchers have followed over 350,000 patients over several decades, and the results were recently published in European urology. It is common knowledge that smokers have an increased risk of developing various types of cancer. But there have been relatively few studies specifically focused on analyzing prostate cancer and including clinical information about the cancer.
Extensive research may now help paint a more complete picture of the association between smoking and risk of disease and death from prostate cancer.
The researchers used data on male smoking habits from five Swedish population studies. From 1974 to the present, about 350,000 men have been included in the study. They were then followed for many years using several national registries.
The National Prostate Cancer Registry provided data on type of tumor at diagnosis, reason for detection (by symptoms or PSA test without symptoms), and treatment. During the study period, 24,731 people fell ill with prostate cancer, 4,322 people died as a result of this disease.
Among other things, the researchers found that during the period of time that a PSA test was available as part of routine health care check-ups, smokers generally had a reduced risk of prostate cancer. This is only true for localized prostate cancer, which is most commonly detected with an asymptomatic PSA test.
“A likely explanation for the lower risk of prostate cancer in smokers is that they may be less likely to have an asymptomatic PSA test. On the other hand, smokers have a higher risk of death from prostate cancer, which we observed regardless of tumor stage at diagnosis, so that means all forms of prostate cancer, from low risk to metastatic,” says Sylvia Jochems, Ph.D. and the first author of the study.
The risk was about 20% higher among smokers than among men who had never smoked. The risk increased even more if the smokers were also overweight (BMI 25-30) or obese (BMI over 30). Researchers say it’s now important to determine why smokers have a poorer prognosis if they develop prostate cancer.
“We need to learn more about whether smoking or other risk factors such as sociodemographic factors are causing this association. Another important question is whether it is possible to improve the prognosis by quitting smoking after you have been diagnosed with prostate cancer,” concludes Tanja Stokes, an assistant professor and the final author of the study.