The addition of radiation therapy to androgen-deprivation therapy among men with prostate cancer who are at a high risk of a cancer recurrence significantly improves long-term survival. These results were recently published in the journal of European Urology.
Prostate cancer is the most frequently diagnosed cancer in men aside from skin cancer. An estimated 220,800 new cases of prostate cancer are diagnosed annually in the U.S., with more than 27,500 men dying from the disease.
Prostate cancer is stimulated to grow from exposure to the male hormone, testosterone. Therefore, an important treatment component for prostate cancer includes agents that block the formation of testosterone. This type of treatment is referred to as androgen deprivation therapy (ADT), or endocrine treatment (ET). There are several different types of ADT agents that prevent formation of testosterone through different mechanisms.
Researchers continue to compare different treatment regimens for prostate cancer so that optimal survival can be achieved, while quality of life can be maintained.
Researchers from The Scandinavian Prostate Cancer Group-7 recently conducted a clinical trial to evaluate the effectiveness of radiation, when added to ADT, among men with locally advanced prostate cancer (cancer spread locally outside the prostate, but not to distant sites in the body). The trial included 875 men treated from 1996 to 2002, who were considered to be at a high risk of developing a cancer recurrence.
All men in the trial were treated with lifelong ADT; however one group received additional treatment with radiation therapy.
- At 15 years, death from prostate cancer occurred in 34% of men treated with ADT only, and 17% of men treated with ADT plus radiation.
- The addition of radiation therapy to ADT improved the median overall survival compared to ADT only by 2.4 years.
The researchers concluded among men with locally advanced prostate cancer who have a high risk of developing a cancer recurrence, “Adding prostatic [radiation] therapy to lifelong antiandrogen therapy halves the absolute risk of death from prostate cancer from 34% to 17% 15 years after diagnosis.”
The researchers also stated that “The results after combined treatment are similar to those after radical prostatectomy”, warranting a phase III clinical trial to directly compare treatment with ADT plus radiation therapy to treatment with a radical prostatectomy in this patient population.
Reference: Fossa S, Wiklund F, Klepp O, et al. Ten- and 15-yr prostate cancer-specific mortality in patients with nonmetastatic locally advanced or aggressive intermediate prostate cancer, randomized to lifelong endocrine treatment alone or combined with radiotherapy: final results of The Scandinavian Prostate Cancer Group-7. European Urology. Published online: 29 March 2016. DOI: 10.1016/j.eururo.2016.03.021.