A long-term follow-up of RTOG 9202 (Hanks 2004) indicates that for patients with locally advanced prostate cancer, an additional 24 months of long-term androgen deprivation (LTAD) therapy after radiation therapy (RT) plus short- term androgen deprivation (STAD) therapy improved disease-free survival (DFS) by 60 percent compared to patients who only received RT plus STAD, according to research presented at the American Society for Radiation Oncology’s (ASTRO’s) 57th Annual Meeting.

Men with advanced prostate cancer typically receive androgen deprivation (AD) therapy to reduce the level of testosterone in their bodies.

Hormone therapy alone cannot cure prostate cancer, however, lowering androgen levels can reduce the size of prostate.

RTOG 9202 was a randomised, multi-institution study of 1,554 patients with locally advanced prostate cancer to evaluate the potential benefits of LTAD compared to STAD.

All patients received RT of 44 Gy to 46 Gy to the pelvic lymph nodes and 65 Gy to 70 Gy to the prostate.

Patients were randomised into two groups, with both groups receiving AD for four months—both groups of patients received goserelin and flutamide two months prior to RT and two months during RT.

After RT, the STAD group received no additional AD therapy; the LTAD group received goserelin for 24 months.

This study’s analysis indicates that at 15 years follow-up, the LTAD group continued to show favourable outcomes of DFS compared to the STAD group (16 percent vs 10 percent, HR = 0.72, P<.0001).

Additionally, the LTAD group had less increase in prostate specific antigen (PSA) levels, compared to the STAD group (cumulative incidence 45 percent vs. 61 percent, HR = 0.57, P<.0001).

The incidence of local progression (growth of the cancer in the prostate or immediate area) decreased from 13 percent in the LTAD group compared to 23 percent in the STAD group (HR = 0.53, P<.0001).

The spread of the cancer to other areas also decreased among the LTAD group―the distant metastases rate fell to 17 percent for the LTAD group compared to 26 percent for the STAD group (HR = 0.61, P<.0001).

The overall survival (OS) for the LTAD group was 30 percent, compared to an OS rate of 27 percent for the STAD group (HR = 0.90, P=.12).

“Our findings reinforce the benefit of longer androgen deprivation therapy for patients with locally advanced prostate cancer,” said lead study author Colleen A.F. Lawton, MD, FASTRO and vice-chair of the department of radiation oncology at the Medical College of Wisconsin.

“It is encouraging that 15 years after the initial RTOG 9202 trial, the data continues to emphasise the advantages of LTAD on disease-specific survival, and thus more patients with advanced prostate cancer should be considered for and may benefit from LTAD.”

Source: ASTRO