Androgen Deprivation Therapy for Prostate Cancer Causes Alzheimer’s Disease?
A blog from our Executive Director, Mark Scholz, MD
Dr. Kevin Nead authored an article published in the Journal of Clinical Oncology this month. It created a media sensation and generated multiple calls to the PCRI Helpline. Last week, three separate articles about this topic were posted on the Yahoo home page at the same time.
It’s no surprise that an article on this topic generates wide-spread interest. About 500,000 thousand men in the United States are undergoing prostate cancer treatment with androgen deprivation therapy (ADT). This treatment works by blocking the male hormone levels delivering notable anticancer efficacy and also proven to prolong life in men with prostate cancer. Despite it’s known effectiveness, a variety of side effects can occur, including memory problems. The previously reported studies evaluating this phenomenon seem to indicate that when memory deficits occur, they usually reverse after ADT is stopped.
The research published in the Journal of Clinical Oncology, relied on a new method of searching through patient’s medical charts with computers. No human review of these medical charts were performed. The computer software searched the medical records in an attempt to determine if men on ADT had a higher incidence of Alzheimer’s. The authors report that this new computer searching methodology in detecting a specific medical diagnosis is 74% accurate.
Review of all the charts at Stanford and Mount Sinai hospital unearthed 16,888 prostate cancer patients of which 2,397 were treated with ADT. After the fancy computer analysis, designed to compensate for multiple factors such as patient age and underlying heart disease (both of which lead to Alzheimer’s more frequently), the conclusion was that the ADT-treated men were twice as likely to have developed Alzheimer’s. A total of about 9 cases would have been expected from normal causes, but 18 were actually detected. If these conclusions are accepted as gospel truth, an additional 9 out of 2,397 men treated with ADT would equate to an increased risk of less than half of 1%.
The conclusion that there is tiny increase risk of Alzheimer’s with ADT, needs to be put in context based on what we already know about prostate cancer. First, is it possible that these men have reversible memory problems while still taking ADT? There was no attempt in the study made to determine if the “Alzheimer’s” patients were still on ADT when the diagnosis of Alzheimer’s was made. Second, men treated with ADT are substantially sicker than men who don’t need ADT. There is no way for the computer analysis to compensate for how this may have impacted mental performance. Third, patients getting ADT receive closer medical surveillance and visit physicians more frequently than men who are not receiving ADT. As such, memory problems are more likely to come to medical attention and be diagnosed when men are on ADT. Fourth, general anesthesia (from surgery) is known to cause long-term memory problems. This study did not perform any analysis to determine if surgery was performed with equal frequency in both groups.
In summary, it is not clear from this JCO article whether the men labeled having Alzheimer’s disease had memory problems while still receiving ADT or whether they had true Alzheimer’s, i.e., long-term irreversible memory problems continuing after the ADT was stopped. There is one thing, however, this study does show: At worst, memory problems serious enough to be labeled as “Alzheimer’s” occur in in less than one out of every 200 men treated with ADT.
Article originally posted December 15, 2015, on Prostate Snatchers: The Blog, by Mark Scholz, MD
A board-certified medical oncologist, Mark C. Scholz, MD, serves as medical director of Prostate Oncology Specialists Inc. in Marina del Rey, CA, a medical practice exclusively focused on prostate cancer. He is also the Executive Director of the Prostate Cancer Research Institute. He received his medical degree from Creighton University in Omaha, NE. Dr. Scholz completed his Internal Medicine internship and Medical Oncology fellowship at University of Southern California Medical Center. He is the co-author of the book Invasion of the Prostate Snatchers: No More Unnecessary Biopsies, Radical Treatment or Loss of Potency. He is a strong advocate for patient empowerment.