Among men treated with radical prostatectomy and found to have pT3 prostate cancer (cancer that extends beyond the prostate capsule), adjuvant treatment with radiation therapy reduces the risk of post-treatment PSA increase. The results of this Phase III clinical trial were published in the Journal of Clinical Oncology.
Other than skin cancer, prostate cancer is the most commonly diagnosed type of cancer among men in the United States. Each year, there are approximately 186,000 new diagnoses and more than 28,000 deaths from the disease. Treatment of prostate cancer may involve surgery (radical prostatectomy), radiation therapy, hormonal therapy, or conservative management (“watchful waiting”).
Among men who undergo radical prostatectomy, some will have cancer that is classified as pT3. This means that the cancer has extended beyond the prostate capsule. Previous studies have suggested that adjuvant (post-surgery) radiation therapy reduces the risk of biochemical progression (post-treatment increase in PSA levels), but these previous studies did not focus specifically on men who achieved undetectable PSA levels after surgery.
To explore the effect of adjuvant radiation therapy among men with pT3 prostate cancer and undetectable PSA levels following radical prostatectomy, researchers conducted a Phase III clinical trial. After radical prostatectomy, men were assigned to immediate radiation therapy or to a wait-and-see policy.
The primary objective of the study was to determine whether immediate postoperative radiation therapy would reduce the risk of biochemical progression. Biochemical progression refers to a post-treatment increase in PSA levels.
- After five years 72% of men treated with immediate radiation therapy remained free of biochemical progression compared with 54% of men in the wait-and-see group.
- Radiation therapy was generally well tolerated.
The results of this study suggest among men with pT3 prostate cancer and undetectable PSA after prostatectomy, receipt of adjuvant radiation therapy reduces the risk of post-treatment PSA increase. Additional follow-up will be required to assess the effect of adjuvant radiation therapy on risk of metastasis and overall survival.
Reference: Wiegel T, Bottke K, Steiner U et al. Phase III postoperative adjuvant radiotherapy after radical prostatectomy compared with radical prostatectomy alone in pT3 prostate cancer with undetectable prostate-specific antigen: ARO 96-02/AUO AP 09/95. Journal of Clinical Oncology [early online publication]. May 11, 2009.