A new study suggests that adding immunotherapy to radiation treatment may help men with very aggressive prostate cancer stay cancer-free longer, offering hope for patients facing one of the hardest forms of the disease to treat.
The research was carried out by scientists at Moffitt Cancer Center and published in the Journal for ImmunoTherapy of Cancer.
Prostate cancer affects millions of men worldwide and is one of the leading cancers in older men. Many prostate cancers grow slowly and can often be managed successfully for years. However, some tumors behave very differently.
Grade Group 5 prostate cancer is considered one of the most aggressive forms of the disease. These tumors grow rapidly, spread more easily, and are much more likely to become life-threatening.
Because of this high risk, doctors often use several treatments at the same time in an attempt to control the disease before it spreads further.
In the new study, researchers tested whether immunotherapy could strengthen the effects of radiation treatment.
Immunotherapy works differently from chemotherapy or radiation. Instead of directly attacking cancer cells, it helps the body’s immune system recognize and destroy cancer more effectively.
The drug used in the study was nivolumab, an immunotherapy medicine already used to treat several other cancers.
Cancer cells sometimes avoid immune attack by switching off immune cells through special proteins known as checkpoints. Nivolumab blocks one of these checkpoints, helping immune cells stay active against cancer.
Researchers believed radiation therapy and immunotherapy might work especially well together.
Radiation damages cancer cells and may release signals that help the immune system notice the tumor more clearly. Scientists hoped that giving nivolumab before and during radiation would make the immune response stronger and more effective.
The study enrolled 31 men with newly diagnosed Grade Group 5 prostate cancer.
Every patient received a very intensive treatment plan. This included hormone therapy, which lowers hormones that feed prostate cancer growth, along with two different forms of radiation treatment.
One type of radiation, known as brachytherapy, places radiation directly inside the prostate using special devices. This allows doctors to deliver very high doses directly to the tumor area.
The second type, called external beam radiation therapy, uses machines outside the body to target the cancer with radiation.
Patients started nivolumab about one month before radiation therapy began. The immunotherapy treatment then continued during the radiation process.
Researchers monitored the men using PSA blood tests, which are commonly used to track prostate cancer activity. Rising PSA levels can signal that cancer has returned or is becoming active again.
After two years, about 90% of the patients showed no signs of biochemical recurrence, meaning their PSA levels did not indicate that the cancer had returned.
For a patient group considered extremely high risk, researchers described these results as encouraging.
The treatment also appeared to be relatively safe. Despite combining several strong therapies together, researchers reported no severe toxic side effects during the study.
Another interesting finding involved a genetic biomarker called the Decipher immunosuppression score.
This score looks for clues about how strongly the immune system is interacting with the tumor and whether the cancer may be blocking immune activity. Patients with higher scores appeared to respond better in the study.
Scientists believe biomarkers like this may one day help doctors choose which patients are most likely to benefit from immunotherapy.
Study leader Kosj Yamoah explained that the team wanted to engage the immune system early so it would already be active when radiation began damaging tumor cells.
Researchers think this timing may help the immune system recognize cancer cells more effectively and attack remaining tumor tissue.
Even though the results are promising, experts stress that the findings are still preliminary.
The study was relatively small and included only 31 patients. It also lacked a randomized comparison group receiving standard treatment alone. Because of this, researchers cannot yet say with certainty that nivolumab improved outcomes.
Longer follow-up will also be important because prostate cancer can sometimes return years after treatment.
The next step will involve larger randomized studies designed to directly compare standard treatment against the combination approach tested in this trial.
Researchers also hope to learn which patients benefit most and whether certain tumor characteristics or biomarkers can predict success.
The findings are important because aggressive prostate cancer remains challenging to treat despite major advances in cancer therapy. Many patients eventually experience recurrence even after intensive treatment.
Scientists are increasingly interested in combining immunotherapy with radiation because the two treatments may strengthen each other in ways that neither can achieve alone.
The study offers hope that future prostate cancer treatment may become more personalized, using immune biomarkers and combination therapies to improve outcomes for men with the highest-risk disease.
While more research is needed before treatment guidelines change, the early results suggest that activating the immune system alongside radiation therapy may become an important strategy in the fight against aggressive prostate cancer.
If you care about prostate cancer, please read studies about 5 types of bacteria linked to aggressive prostate cancer, and new strategy to treat advanced prostate cancer.
For more information about prostate cancer, please see recent studies about new way to lower risk of prostate cancer spread, and results showing three-drug combo boosts survival in metastatic prostate cancer.
Source: Moffitt Cancer Center.
