A trial looking at the immune system in men having radiotherapy for prostate cancer (Prostate Radiotherapy Pneumovax Study, or PRP)

The research team were able to measure certain immune system cells. They suggest that radiotherapy would not  affect possible immunotherapy treatments for early stage prostate cancer.

This study recruited 15 men,

• 7 men with prostate cancer who were waiting to have radiotherapy
• 1 man with prostate cancer who wasn’t going to have radiotherapy
• 7 men who didn’t have prostate cancer

The research team took blood samples from the men with prostate cancer twice during radiotherapy and once after they finished treatment.

As part of the study, the research team developed a new test that could measure immune cells. They used this test to measure levels of certain immune cells in the blood samples.

Some cancers cause an increase in the levels of white blood cells called regulatory T cells (Tregs). These cells make the immune system less effective at fighting cancer. The research team found that the level of Tregs didn’t increase in men with prostate cancer. So treatments that use the immune system may work in these men. But the level of Tregs did increase a bit after radiotherapy. So they would need to be controlled for immunotherapies to work at this stage of treatment.

They also found that the level of white blood cells called lymphocytes didn’t change during or after radiotherapy. This means that some immunotherapies may work just as well after radiotherapy.

The study team concluded that they had successfully developed a new way of measuring immune cells that could be used in the future. And that immunotherapy may be a useful treatment after radiotherapy for prostate cancer.

We have based this summary on information from the team who ran the trial.  As far as we are aware, the information they sent us has not been reviewed independently (peer reviewed ) or published in a medical journal yet. The figures we quote above were provided by the trial team. We have not analysed the data ourselves.