People With MS May Have Lower Cancer Risk

Mar. 31 -- TUESDAY, March 31 (HealthDay News) -- People with multiple sclerosis may have a lower overall risk of developing cancer, Swedish researchers report.

The study, which tracked the medical records of more than 20,000 MS patients for 35 years, "found that they had some 10 percent decreased overall cancer risk compared with those without the disease," said lead researcher Dr. Shahram Bahmanyar, from the Clinical Epidemiology Unit at the Karolinska Institute in Stockholm.

The study did find an increased risk among MS patients for certain malignancies, such as brain and bladder cancers.

Prior studies into the risk for cancer for people with MS has produced a hodgepodge of findings. The disease has been associated with a reduced risk for digestive, respiratory, prostate and ovary cancers, as well as non-Hodgkin lymphoma, but other studies have noted increased risks for urinary tract and nasopharyngeal cancers. To complicate matters even further, breast cancer risk has been reported as higher, lower or unchanged among those with MS, the researchers noted.

The new study sought to settle the matter. So, the Stockholm team compared the cancer risk in 20,276 people with MS to almost 204,000 people without the disease.

The reduction in cancer risk that they discovered was even more pronounced in women, according to the report, which appears in the March 31 issue of Neurology.

The trend wasn't all positive: The risk of developing brain tumors, plus bladder and other urinary cancers, was increased by up to 44 percent among MS patients compared to those without the illness, the researchers noted.

So, were genes that influence MS also keeping overall cancer rates down? "To determine whether there was a possible genetic link between multiple sclerosis and lower cancer risk, we studied the risk among parents of MS patients," Bahmanyar said. However, he and his colleagues "found that [the parents] did not have a notably increased or decreased overall cancer risk," suggesting that genes are not the causative factor.