Should hormone therapy be added to intensive radiotherapy in early prostate cancer?

This study examined the potential benefit of early hormone therapy added to intensive radiotherapy in the treatment of men with intermediate-risk local prostate cancer.

Overall survival was found to be improved with higher radiation dosage. However, the researchers noted that early hormone therapy does generally not benefit treatment outcome for intermediate-risk prostate cancer.

Intermediate-risk prostate cancer is typically localized to the prostate gland, but associated with an elevated risk of experiencing a cancer progression or recurrence, after initial treatment. Radiotherapy is commonly used to treat local prostate cancer. In cases of intermediate-risk prostate cancer, the delivery of high doses of radiotherapy to the prostate has been recommended for improved cancer outcomes.

Hormone therapy such as androgen deprivation therapy (ADT) is often used to reduce the risk of recurrence after local treatment. ADT targets the production of androgens (male sex hormones such as testosterone) and reduces their effect on cancer cell growth. ADT may also be administered early to reduce tumor size prior to radiotherapy. Whether ADT adds benefit to high-dose radiotherapy in intermediate-risk prostate cancer has not been fully studied.

This trial included 14,126 men with intermediate-risk prostate cancer. Men were divided according to ADT received, or no ADT received, prior to radiotherapy. All men were treated with radiotherapy (using external beam radiation) of either a low dose (70-72 Gy), intermediate dose (72.1-77.9 Gy), high dose (≥78 Gy), or a combination of low-dose external radiotherapy with brachytherapy (radiation from inside the prostate).

Analysis showed no significant benefit of adding ADT to radiotherapy in terms of overall survival, regardless of radiation dosage. At five-year follow-up, 87% of men that received ADT and radiotherapy had survived, compared to 88% of men that did not undergo ADT. Overall survival at eight-year follow-up was 73% in the group of men that received ADT and 75% in the group of men with no history of ADT treatment. However, a small subset of men with 3 or more high-risk factors (including tumor stage, histology and blood markers) were noted to benefit from early treatment with ADT.

The type of radiotherapy was found to significantly impact treatment outcome. Men receiving a high radiation dosage or a combination of low-dose radiotherapy with brachytherapy were about 35% more likely to survive the duration of the study follow-up. However, a higher radiation dosage also increases potential side-effects such as urinary symptoms, cramps, and bleeding. The side-effects commonly associated with ADT included erectile dysfunction, fatigue, and weight gain.

The researchers concluded that there was no overall benefit of ADT treatment when combined with high-dose radiotherapy among intermediate risk patients.