ASTRO: Long-Term Androgen-Deprivation Therapy Plus High-Dose Radiation Therapy Improves Biochemical Control and Survival Rates in Prostate Cancer
Prostate cancer patients who receive high-dose radiation therapy followed by a longer period of androgen-deprivation therapy have higher 5-year biochemical disease–free survival and overall survival rates compared to patients who receive high-dose radiation therapy and a shorter duration of androgen-deprivation therapy, according to research presented at the American Society for Radiation Oncology’s (ASTRO) 56th Annual Meeting (Abstract PL-02).
Study Details
Radiation therapy combined with androgen-deprivation therapy is an established standard of care for patients with locally advanced prostate cancer. This multicenter study evaluated whether high-dose radiation therapy combined with long-term androgen-deprivation therapy for 28 months was associated with better patient outcomes compared to high-dose radiation therapy combined with short-term androgen-deprivation therapy for 4 months.
Between 2006 and 2010, 362 patients were enrolled in the study at nine cancer centers in Spain, and 355 patients met all study criteria. The patients had prostate cancer with no lymph node involvement and no metastases and unfavorable risk factors and prostate specific antigen (PSA) levels of less than 100 ng/mL. The study’s primary endpoints were biochemical disease–free survival and toxicity scores.
All patients received 4 months of neoadjuvant and concomitant androgen-deprivation therapy plus high-dose radiation therapy. The median radiation dose to the prostate was 78 Gy. Patients were then randomly assigned to two groups: 177 patients received adjuvant goserelin (Zoladex), a luteinizing hormone that suppresses production of testosterone, subcutaneously for 24 additional months, and the remaining 178 patients received 4 months of androgen-deprivation therapy. A comparable number of intermediate-risk patients and high-risk patients were assigned to each group. There were 166 intermediate-risk patients (85 in the long-term group; 81 in the short-term group), and 189 high-risk patients (92 in the long-term group; 97 in the short-term group).
Survival Benefit With Long-Term Androgen-Deprivation Therapy
A total of 11 patients in the long-term androgen-deprivation therapy group and 15 patients in the short-term androgen-deprivation therapy group had biochemical disease–free survival, according to Phoenix Consensus definition (P = .003).
After a median follow-up of 63 months, the five-year biochemical disease–free survival was significantly higher in the long-term androgen-deprivation therapy group (89.8%) compared to the short-term group (81.3%) (P = .019).
The study also evaluated metastasis-free survival and overall survival. The 5-year metastasis-free survival was also significantly higher for the long-term androgen-deprivation therapy group—93.6% compared to 83.4% in the short-term androgen-deprivation therapy group (P = .009). There was also a significant benefit in the overall survival for patients treated with long-term (94.8%) vs short-term androgen-deprivation therapy (86.1%, P = .009), this benefit being more evident in patients with high-risk prostate cancer (P = .010). Radiation-related side grade 2 effects were acceptably low and not significantly different in both groups.
“The management of patients with intermediate- and high-risk prostate cancer is highly challenging,” said lead study author Almudena Zapatero, MD, PhD, a radiation oncologist at Hospital Universitario de la Princesa in Madrid. “The clinician must choose the type of local treatment as well as the optimal timing and sequence of hormone therapy. Moreover, rapid and ongoing advances in treatment options require that physicians consider options that can impact both survival and quality of life. The 5-year results of our study show that the combination of high-dose external radiotherapy utilizing new technologies, such as intensity-modulated radiation therapy, volumetric-modulated arc therapy, and image-guided radiation therapy, and 28 months of hormone therapy are a very successful combination to achieve positive prostate cancer control. Of paramount consideration, long-term androgen-deprivation therapy in combination with high-dose radiation therapy provides good quality of life through a noninvasive, safe and efficient treatment approach for patients with high-risk prostate cancer.”
The study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
