December 23, 2019
By Anne Harding
NEW YORK (Reuters Health) - Medicare patients who receive longer-term androgen-deprivation therapy (ADT) for prostate cancer (PCa) are at increased risk of Alzheimer's and dementia, according to new findings.
"Our findings call for judicious use of ADT in men presenting with prostate cancer, as ADT is associated with many long-term risks, including dementia. Moreover, men at risk of cognitive dysfunction may need special attention (monitoring) in that regard," Dr. Quoc-Dien Trinh of Brigham and Women's Hospital and Harvard Medical School in Boston told Reuters Health by email.
ADT can reduce mortality and slow disease progression in PCa, but it has been linked to adverse effects including osteoporosis and fractures, diabetes, heart disease and mental illness, Dr. Trinh and his colleagues note in Prostate Cancer and Prostatic Diseases. Some studies have found ADT increases dementia risk, but others have not.
The researchers looked at SEER-Medicare-linked data for more than 100,000 men 66 and older diagnosed with localized or locally advanced PCa in 1992-2009. Thirty-eight percent were prescribed ADT.
Patients who received ADT had a significantly higher risk of developing all-cause dementia (hazard ratio 1.17) and Alzheimer's (HR 1.23), and a borderline-significant increase in risk of psychiatric-service use (HR, 1.10) compared with those not treated with ADT.
Men who had ADT for seven months or longer were at particularly high risk of dementia and Alzheimer's (HR, 1.25 and 1.34, respectively). Longer-duration ADT was also associated with an increased risk of using psychiatric services (HR, 1.09), although this result was not statistically significant.
Men on shorter-term ADT, however, were not at increased risk of dementia or Alzheimer's.
The researchers note that the findings are "reassuring" for men who don't need to take long-term ADT. However, patients must often take ADT for longer.
"Patients who choose radiation therapy to treat locally advanced prostate cancer often require concomitant ADT for at least 18 months, if not more," Dr. Trinh said. "Patients presenting with metastatic prostate cancer often require ADT indefinitely."
Prospective studies are needed to confirm the findings, according to the researcher, "especially given some disagreement between retrospective observational studies."
SOURCE: https://go.nature.com/2YJ838m Prostate Cancer and Prostatic Diseases, online November 29, 2019.
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