Wednesday, May 22, 2024 A longer follow-up from the PR13/RADICALS-RT international study confirms that having radiotherapy only if the cancer returns, as opposed to having it soon after surgery, is a better approach for most people. People who have surgery to remove their prostate do not need immediate radiotherapy to prevent their cancer from returning. These longer term results from the PR13/RADICALS-RT trial were published in Annals of Oncology today. "RADICALS-RT shows that routine preventative radiotherapy is not required after surgery but can be effective when used at an early sign of relapse for those who develop cancer recurrence. For prostate cancer patients this means that they can avoid unnecessary treatment and its associated long-term side effects," says Dr Charles Catton the PR13 study co-chair Radiation Oncologist and Clinician Investigator at Princess Margaret Cancer Centre. Radiotherapy is widely used after surgery for prostate cancer. Previous research had shown that surgery plus radiotherapy for everyone was better at preventing the cancer returning than surgery alone. However, it is not clear which people need radiotherapy and when. To address these questions, the RADICALS-RT trial compared if a policy of giving radiotherapy soon after surgery to all people was better than using radiotherapy only if there was early evidence the cancer had returned. The early evidence would be rising PSA, a blood marker that indicates prostate cancer, even if the values were still very low. RADICALS-RT was an international trial that included 1,396 men from the UK, Denmark, Canada and Ireland. They were allocated, soon after surgery, into two groups at random:One group was planned to have radiotherapy soon after surgery.One group was planned to be followed and radiotherapy given only if their prostate cancer returned.In 2020, researchers from the MRC Clinical Trials Unit at UCL published the first set of results from RADICALS-RT, which found that this group of men who had surgery to remove their prostate did not benefit from immediate radiotherapy. The team have now followed up these men for around eight years on average. These updated results confirm that there is no clear evidence of a benefit from a policy of giving radiotherapy soon after surgery, when compared to giving radiotherapy only if the cancer returns. The trial also found that radiotherapy soon after surgery resulted in a higher risk of unwanted side-effects, such as urinary and bowel problems.In the group who were planned to be followed and given radiotherapy only if the cancer returned after surgery, around half avoided the need for radiotherapy.These results mean that radiotherapy may be delayed or even omitted following prostate removal for some people with prostate cancer. Instead, they can be regularly monitored, with radiotherapy only used if their cancer shows early signs of coming back.As these results support that giving radiotherapy only when needed is a better approach for most people, the RADICALS-RT researchers believe that this should be the standard procedure after surgery. In Canada, the RADICALS-RT trial was conducted by the Canadian Cancer Trials Group and supported by the Canadian Cancer Society. The RADICALS-RT trial was funded by Cancer Research UK and Medical Research Council. Further informationRADICALS-RT paper in Annals of OncologyNews story RADICALS-RT 2020 resultsRADICALS study pageRADICALS-RT paper in The Lancet (2020)Animated abstract about RADICAL-RT 2020 results