Tag Archives: hormone therapy

ADT and Alzheimer’s Disease: risk/benefit


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The July 3 issue of JAMA Network contained a disturbing article regarding the risk of developing Alzheimer’s disease or dementia following use of androgen deprivation therapy (ADT). Using the SEER-Medicare database, the authors identified a cohort of men aged 66 or older who were diagnosed with localized or advanced prostate cancer between 1996 and 2003. The data on what happened to them in the next 10 years were then analyzed according to whether they received ADT or not in the 2 years following their diagnosis.  These were older men (74-76) who mostly lived in metropolitan areas, and 3/4 were caucasians, 2/3 were married, with just over 1/3 coming from low socioeconomic backgrounds. There were 62,330 men who received ADT, and 91,759 who did not in the final groups analyzed.

With a mean followup of 8.3 years, the risk of developing Alzheimer’s disease among the control group was 9.4% but increased to 13.1% if the men received ADT (P<0.01). Similarly, a diagnosis of dementia increased from 15.8% to 21.6% with ADT exposure, and there was evidence that the longer the men were on ADT, the worse the risk. These data are disturbing to me on two levels. First, I was unaware that 75 year old men have such a high risk for developing Alzheimer’s disease or dementia in their next decade; and second, as a frequent prescriber of ADT for men with prostate cancer in general, and particularly for those receiving curative intent radiotherapy for high risk disease, it adds to the challenge of how long to recommend such therapy (if at all). The risk curve for Alzheimer’s is shown in this figure:

Screen Shot 2019-09-04 at 2.58.07 PM

The benefit of adding ADT to curative intent radiotherapy has been demonstrated in a large number of studies dating back to the 1990’s. For example one of the most cited studies compared the survival and prostate cancer specific survival of adding 3 or 6 months of hormone therapy to radiotherapy in patients with advanced local disease. The advantage of 6 months (compared to none or 3 months) of ADT is shown in this figure, and is about 10%, somewhat better than the increased risk of developing Alzheimer’s that is probably created.

Screen Shot 2019-09-08 at 6.19.23 PM

The details of these kinds of comparisons are quite complicated – for example trying to separate out various categories of “high risk” or “higher risk” prostate cancer, etc. as reflected in this editorial by Dr. D’Amico. Numerous other studies continue to support the use of ADT to improve outcomes of radiotherapy – the challenge being how long to continue it and weighing toxicities (cardiac, quality of life, dementia risk, etc.) vs the advantage in terms of prostate cancer control. Dr. D’Amico looks forward to better information in his final statement, “During the next few years, data that will shed light on whether more than 6 months of AST is needed to prolong survival in men treated with RT for localized high risk or locally advanced prostate cancer will be provided by the completed EORTC randomized study 22961.” Stay tuned, and if you are told to take ADT to improve the outcome of radiation to your high risk localized prostate cancer, discuss the details with your physicians! How old you are, what is in your family history, and your own thoughts regarding risks of prostate cancer recurrence/death or dementia are important issues.

 

 

 

 

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3 Articles and a forth


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OK, I admit to a sleazy, seemingly misspelled word to attract attention. At least I didn’t tweet it at 3AM. So what about the “forth”? I’m using it to remind you to sally forth in your search for information about prostate cancer. I previously wrote a blog giving some practical instructions on how to find the latest research publications on prostate cancer that you can find here. Another possibility, if you want to be overwhelmed is to subscribe to the Prostate Cancer Daily, published by Uro Today. So far as I can tell it is open to all, presents the original abstracts, and links via PubMed to the article itself. I now realize that the prediction of patients knowing more than their doctors about a given condition is glaringly obvious, something I discussed when I first wrote about the Internet and Oncology two decades ago.

So, on to the 3 articles: Typically, the most important articles in medicine are published in high profile journals. The premier one for medical oncology is the Journal of Clinical Oncology, JCO. The editors recently published a “best of genitourinary cancer, 2017” edition in coordination with what we medical oncologists call “GU ASCO” (actually co-sponsored by ASCO, ASTRO, and SUO). I thought it would be of interest to briefly re-cap the 3 prostate articles chosen for that edition.

ARTICLE 1: Enzalutamide Versus Bicalutamide in Castration-Resistant Prostate Cancer: The STRIVE Trial. This study compared the more potent anti-androgen, enzalutamide (Xtandi™) to the older drug, bicalutamide (Casodex™) in patients who had become resistant to initial hormonal therapy. About 2/3 of the men had positive scans, while in 1/3 the resistance was detected only by a rising PSA without a positive scan. As we might have expected from the way enzalutamide was developed, it was clearly superior, with progression free survival of 19 months for enzalutamide vs. 6 months for bicalutamide. In an ideal world, we would use enzalutamide instead of bicalutamide in almost all cases where an antiandrogen is indicated. However, the increased cost of this drug is dramatic, and there may be other options or confounding issues with interpretation of the study.

ARTICLE 2: Randomized Phase III Noninferiority Study Comparing Two Radiotherapy Fractionation Schedules in Patients With Low-Risk Prostate Cancer. This article reports on one of many studies looking at whether radiation therapy treatment times can be safely shortened by increasing the dose of radiation given with each treatment and giving fewer treatments (fractions). The underlying principles are that tumor cells cannot repair DNA damage from radiation as quickly as normal cells, so giving radiation in small fractions daily allows killing of the tumor while normal cells repair most of the damage. Giving all of the radiation at once would kill every cell (and the patient).  Experimentally, prostate cancer cells may be more susceptible to larger fractions, and this study demonstrated that a radiation therapy course could be safely shortened from 41 sessions to 28 sessions with similar “cure” rates at 5.8 years of followup. This is a general trend in radiation therapy for prostate cancer. Using newer radiation focusing technologies (IMRT, IGRT, Stereotactic radiosurgery, etc.) it is possible to treat prostate cancer with as few as 5 treatments, although the long term efficacy is still unknown, and the addition of androgen deprivation to radiation treatment at any dose also improves efficacy. How to combine these approaches, the optimal duration of ADT, and which patients should stay with the older methods is still uncertain.

ARTICLE 3: Improved Survival With Prostate Radiation in Addition to Androgen Deprivation Therapy for Men With Newly Diagnosed Metastatic Prostate Cancer. Proudly, many of the authors on this article are from the University of Colorado Cancer Center. The authors used the National Cancer Database to determine whether patients with metastatic prostate cancer, traditionally treated with hormone therapy (ADT) only (although more recently with hormone therapy plus chemotherapy) benefit from also radiatiScreen Shot 2015-10-30 at 11.02.16 AMng the prostate itself. The analogy would be burning down the barn after the horse has left (with apologies to my radiation therapy colleagues who never like to compare radiation
treatments to burning). The patients who had their prostates radiated
had a 5 year survival of 49% compared to 33% for those receiving ADT alone. Removing the prostate surgically also worked. The prostate may also be a site where metastatic cells from another location return, as illustrated in this picture and discussed here. The take home message is that the cancerous prostate may continue to “seed” cancer cells to the rest of the body, or be a home for circulating tumor cells and getting rid of it, even though not curative, may be a good idea (toxicities and costs aside).

Consider yourselves updated! (sort of…)

 

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