A number of recent studies have tied unexpected and serious side effects to androgen deprivation therapy (ADT), a commonly used hormonal treatment regimen for prostate cancer that reduces male androgen (testosterone and dihydrotestosterone) levels.

The most recent report linked ADT to new cataracts in some 66,000 prostate cancer patients older than age 67. Based on their results -- a 9 percent uptick in cataracts for men treated with ADT versus those who weren't -- researchers estimate as many as 5 percent of new cataracts found in prostate cancer patients may be connected to hormonal therapy.

Older prostate cancer patients treated with ADT, according to a Journal of the National Cancer Institute study, were as much as 40 percent more likely to be diagnosed with colorectal cancer. Also, the longer a patient took ADT, the greater their risks.

In the third study, the age of the patient and duration of treatment appeared to be the key factors in worsening the risks of fracture among some 47,000 men older than age 65 who were diagnosed with localized prostate cancer and had a history of fractures. Almost half of the patients monitored had used ADT for more than two years or had undergone orchiectomy (surgical castration).

ADT patients increased their risk of a first fracture by 20 percent and a second fracture by 57 percent after two years of treatments. Even worse, men older than age 74 who were treated with ADT for more than two years more than tripled their risk of fracture, compared to younger men in the 66-74 age range.

Annals of Epidemiology November 26, 2010

Medline Plus December 27, 2010

ScienceDaily November 12, 2010

ScienceDaily November 12, 2010

Journal of the National Cancer Institute, Vol. 102, No. 23, p. 1760-1770, December 1, 2010