Hormone + Radiation Therapy for Prostate Cancer

(SENTRY Trial)

This trial tests whether hormone therapy (Androgen Deprivation Therapy) combined with radiation (External Beam Radiation Therapy) effectively treats prostate cancer. It compares two groups: one receives hormone therapy for 6 months, and the other for 18 months, both alongside radiation. The study aims to determine if the shorter treatment is equally effective in preventing the cancer from becoming resistant. Men with high-risk prostate cancer, who have not undergone surgery or other prostate cancer treatments, may be suitable candidates for this trial. Participants will attend checkups and monitor their medication doses for at least five years. As a Phase 2 trial, this research measures the treatment's effectiveness in an initial, smaller group of people.

The trial does not specify if you need to stop taking your current medications. However, if you are currently on androgen deprivation therapy or other prostate cancer treatments, you may need to discuss this with the trial team, as prior systemic therapy for prostate cancer is an exclusion criterion.

Research has shown that combining radiation therapy with short-term hormone treatment, known as androgen deprivation therapy (ADT), is generally safe but may cause some side effects. One study found that short-term ADT with radiation improved survival rates for prostate cancer patients. However, some patients experienced side effects like tiredness, hot flashes, and loss of muscle strength. These side effects are important to consider but can usually be managed.

For longer-term ADT, studies suggest it has similar safety, with common side effects including low energy, mood changes, and weight gain. These are typical of hormone treatments and usually aren't severe enough to stop treatment.

Researchers are excited about these treatments because they explore the combination of hormone therapy and radiation in new ways for prostate cancer. The first approach pairs radiotherapy with short-term androgen deprivation therapy (ADT) for six months, potentially enhanced by an androgen receptor pathway inhibitor. This may offer a quicker, more intense treatment option compared to standard long-term hormone therapy. The second approach involves radiotherapy with a longer, 18-month course of ADT, which could provide sustained tumor control. These strategies aim to optimize how hormone therapy is used alongside radiation, potentially improving outcomes and reducing side effects compared to current options.

Research shows that combining radiation therapy with short-term hormone therapy (ST-ADT), which participants in this trial may receive, can improve outcomes for prostate cancer patients. One study found that 62% of patients who received this combined treatment were still alive after 10 years. Another study reported a 74.4% survival rate after 5 years, with 89.1% of patients surviving specifically from prostate cancer. In this trial, another group will receive longer hormone therapy, such as for 18 months, along with radiation. This longer treatment has been linked to a 63% reduction in the risk of death or cancer spreading. These findings suggest that both short-term and long-term hormone therapy with radiation are effective, but the longer treatment might offer extra protection against cancer progression.²³⁶⁷⁸