CT planning of high-dose-rate brachytherapy to the prostate. Image Source: AstraZeneca

BOSTON—Men over 70 years of age with early-stage prostate cancer have 20 percent higher mortality if they are treated with hormone therapy before being treated with brachytherapy, compared to men who are treated with brachytherapy alone, according to a large cohort study presented Tuesday at the 50th annual meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO).

The researchers said the study shows that hormone therapy can have negative effects on survival, which “is important to consider when weighing treatment options, especially since hormone therapy, or neoadjuvant hormone therapy (NHT), is sometimes used to shrink the prostate before brachytherapy treatment of localized prostate cancer but does not improve the patient's chance of being cured.”

“Our study shows that for men over 70 with early-stage prostate cancer, androgen deprivation therapy as a form of treatment may do more harm than good,” said the study’s lead author Amy Dosoretz, MD, a radiation oncology resident at the Harvard Radiation Oncology Program in Boston. In older patients, the risks of androgen deprivation need to be carefully weighed by doctors when designing the proper treatment plan.”

Dosoretz noted that the use of brachytherapy in prostate cancer patients has significantly increased over the past few decades, especially in the low-risk patient population. “In the past, hormone therapy has often been used in these patients, prior to the brachytherapy procedure, in order to make the procedure easier. However, recent studies have alerted us to the fact that hormone therapy may have many more risks than were previously appreciated.”

The cohort study included more than 2,000 men with localized prostate cancer, who were treated with NHT and brachytherapy or with brachytherapy alone, at centers within the 21st Century Oncology consortium between 1991 and 2005, according to Dosoretz. She said that the patients were followed up for a mean of 4.8 years. The study group assessed the effect of hormone therapy on patients’ overall mortality.

They found that men in this age group with localized prostate cancer who were treated with both NHT and brachytherapy had a 20 percent increased risk of dying, compared to men who were not treated with NHT.

“These results are particularly interesting, since two previous studies that examined similar populations contradicted each other in terms of how hormone therapy impacts the risk of death among prostate cancer patients in this age group,” Dosoretz said.

Dosoretz noted that the researchers did not have access to the causes of mortality within their patient population, and because it was an elderly group, there could have other causations of death, such as cardiovascular complications.

Based on their results, Dosoretz said that she and her colleagues are cautioning radiation oncologists to weigh the risks of utilizing hormone therapy in low-risk older patient population when designing treatment plans.

Louis B. Harrison, MD, ASTRO chair, who moderated Dosoretz’ presentation, said that the study is “one of those studies that challenges the paradigm.” He said that as new information unfolds, it becomes more important to weigh the risks and benefits of when and with whom to use hormone therapy. He also noted that other studies presented at the ASTRO meeting have suggested the benefits of hormone therapy, especially in high-risk patients.