For men with localized, intermediate-risk prostate cancer, treatment with a combination of radiation therapy and short-term androgen-deprivation therapy results in better outcomes than treatment with radiation therapy alone. These results were published in the New England Journal of Medicine.
Treatment options for men with early-stage prostate cancer include surgery, radiation therapy, and active surveillance (close monitoring but no treatment unless the cancer shows signs of worsening).
A type of treatment that is often used in men with more advanced prostate cancer is androgen-deprivation therapy (ADT). This treatment slows prostate cancer growth by reducing exposure of the cancer to testosterone. ADT is commonly used for men with metastatic prostate cancer and has also been shown to improve outcomes when added to radiation therapy for the treatment of men with locally advanced prostate cancer. Less is known about the effect of adding short-term ADT to radiation therapy among men with early-stage prostate cancer.
To assess short-term ADT in the treatment of early-stage, localized prostate cancer, researchers conducted a study among nearly 2,000 men. Study participants had stage T1b, T1c, T2a, or T2b prostate cancer and a prostate-specific antigen (PSA) level of 20 ng/ml or less. Half the men were treated with radiation therapy alone and half were treated with radiation therapy and four months of ADT.
- Ten-year overall survival was 62% among men treated with radiation therapy plus ADT compared with 57% among men treated with radiation therapy alone.
- Ten-year risk of dying from prostate cancer was 4% among men treated with radiation therapy plus ADT compared with 8% among men treated with radiation therapy alone.
The researchers also evaluated whether the benefit of ADT varied by whether the cancer was low-risk or intermediate-risk. The cancer was classified as low-risk if the Gleason score was 6 or less, the PSA was 10 ng/ml or less, and the clinical stage was T2a or lower. Intermediate risk cancers had at least one of the following: Gleason score of 7, PSA between 10 ng/ml and 20 ng/ml, or clinical Stage T2b.
- A benefit of adding ADT to radiation therapy was only observed among men with intermediate-risk prostate cancer. The addition of ADT did not appear to benefit men with low-risk prostate cancer.
These results suggest that the addition of short-term androgen-deprivation therapy to radiation therapy may benefit men with early-stage, intermediate-risk prostate cancer.
Radiation therapy techniques have evolved since this study was conducted, and it’s possible that the value of ADT may be different with newer approaches to radiation therapy. Another study is underway to address this question.
Reference: Jones CU, Hunt D, McGowan DG et al. Radiotherapy and short-term androgen deprivation for localized prostate cancer. New England Journal of Medicine. 2011;365:107-18.