Cancer, Chemo May Lower Alzheimer's Risk, Study Suggests By Alan Mozes

HealthDay Reporter

MONDAY, July 15 (HealthDay News) -- If battling a deadly disease can be said to have a silver lining, this might be it: Many forms of cancer appear to lower the risk for developing Alzheimer's disease, new research suggests.

After sifting through the health records of nearly 3.5 million patients, investigators concluded that most kinds of cancer seem to confer some degree of protection against Alzheimer's, reducing risk of the age-related brain disorder by anywhere from 9 percent to 51 percent.

And they have also linked a common form of cancer treatment -- chemotherapy -- to a lower risk for developing Alzheimer's-related dementia.

"We found that the majority of cancers were associated with a decreased risk of [Alzheimer's disease]," said study lead author Dr. Laura Frain, a geriatrician with the VA Boston Healthcare System. "This does not mean that if you have cancer you won't get [Alzheimer's], but that you may have a decreased risk, depending on the cancer type."

Chemotherapy conferred additional protection against Alzheimer's in most cancers, with the exception of prostate cancers, Frain said. "Our findings suggest that some chemotherapies may have a neuroprotective action. Further studies are needed to confirm this," she added.

Frain and colleagues are scheduled to present their findings Tuesday at the Alzheimer's Association international conference in Boston. The research uncovered an association between some cancers and possible protection from Alzheimer's, but it did not prove the existence of a cause-and-effect relationship.

Frain's findings come on the heels of another large study published online July 10 in Neurology, in which an Italian team also unearthed a potential protective link between cancer and Alzheimer's disease.

In that case, investigators identified an inverse relationship between cancer and Alzheimer's disease, in which having cancer appeared to lower the risk for Alzheimer's by 35 percent, while having the progressive brain disease lowered the risk for cancer by 43 percent.

For the current effort, Frain's team pored through the medical paperwork of millions of American veterans who moved through the VA health care systems between 1996 and 2011.