Trials close in on optimal ADT duration in high-risk prostate cancer

Clinically relevant differences, defined as ones of at least 10 points on the 100-point linearly transformed scales, were seen between men who did and did not have testosterone recovery for two of the global quality of life items – trouble doing strenuous activities and trouble taking long walks – and three of the prostate-related quality of life items – hot flushes, interest in sex, and sexual activity.

“In high-risk prostate cancer treated with radiation therapy and ADT, patients who recover normal testosterone levels have a better quality of life,” said Dr. Nabid. “There is a major advantage in the use of 18 months of ADT instead of 36 months since a higher proportion of patients recovered normal testosterone levels in a much shorter time without any apparent detriment in long-term outcomes.”

“If we succeed to demonstrate that 18 months is at least equal to 36 months, it’s a big jump because it’s a matter of quality of life, it’s a matter of cost also,” he added. The investigators expect to be able to publish final efficacy and quality of life results next year.

In the meantime, clinicians can follow national guidelines, according to Dr. Nabid. “If you look at the guidelines, like the NCCN guidelines for the U.S., what is written is that the long-term [ADT] could be between 24 and 36 months. So my advice would be, even if you wait for the final paper, to go for 24 months. It’s a good beginning,” he asserted.

However, “you have to use your clinical judgment,” he added, agreeing that disease factors can be used to further stratify high-risk patients; additionally, age, comorbidities, and other factors will play a role in tailoring the duration of ADT. And importantly, “one has to discuss this with his patients.”

Dr. Lawton noted that the definition of long-duration ADT has varied by world region, and has typically been 28 months in the United States and 36 months in Europe. On the basis of this trial’s findings, “I do think that 18 months is potentially our new long-term hormone therapy option. That data isn’t out in print yet, other than in abstract form, But I think going forward, the question for us should be, can we shorten it from there,” she said. “I don’t know that we’ve nailed [the optimal long duration], but we are certainly heading in the right direction.”

Dr. Zapatero disclosed no conflicts of interest; the trial was supported in part by the AstraZeneca Fund. Dr. Nabid disclosed ties with AstraZeneca and Sanofi; AstraZeneca collaborated on the trial.