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Hormone therapy can delay prostate cancer metastasis after surgery and radiotherapy

Findings from the CCTG PR13/RADICALS-HD study confirm that adding two years, compared to six months of hormone therapy delays prostate cancer spread in people who had surgery to remove the prostate followed by radiotherapy.

People with prostate cancer who have had surgery to remove their prostate and who then receive radiotherapy can benefit from also having two years of hormone therapy. These results from the PR13/RADICALS-HD trial were recently published in The Lancet journal.

Dr Fred Saad
Dr Fred Saad, the CCTG PR13 Study Co-Chair, Head of urologic oncology and Director Prostate cancer research at the University of Montreal Hospital Center

"Unlike current practice, RADICALS HD suggests that hormonotherapy may not always be necessary for men receiving radiation following surgery for prostate cancer," says Dr Fred Saad, the CCTG PR13 Study Co-Chair, Head of urologic oncology and Director Prostate cancer research at the University of Montreal Hospital Center. “However, if hormonotherapy is felt to be necessary, a longer duration appears to be more effective than a shorter duration.”

In 2024, approximate 27,900 cases of prostate cancer will be diagnosed in Canada. Many people with localised prostate cancer will have surgery to remove their prostate. It is unclear if radiotherapy, with or without hormone therapy, after surgery should be administered to prevent the cancer from returning. 

The RADICALS-HD clinical trial was led by researchers in the United Kingdom and included people from Canada, Denmark and Ireland. The trial tested whether giving hormone therapy alongside radiotherapy would benefit people who had already had surgery. In this trial, people receiving radiotherapy after surgery were randomly allocated to receive no hormone therapy or six months of hormone therapy, or two years of hormone therapy. People taking part in the trial joined between 2007 and 2024 and were followed-up for around 10 years on average. 


The results from RADICALS-HD were presented in two overlapping comparisons: one comparing no hormone therapy to six months of hormone therapy, the other comparing six months of hormone therapy to two years. The people who participated in the no hormone versus 6 month hormone comparison had cancers that were a slightly less aggressive than those who participated in the 12 month versus 24 month comparison.


RADICALS-HD showed that having two years of hormone therapy delayed the spread of the cancer when compared to having just six months. After 10 years, the proportion of people alive without cancer spreading outside the prostate was 78% in the two years group, compared to 72% in the six months group. At this time, it is not known if one of the treatment groups will have an increased overall survival compared to the other.   In contrast, the study found no benefit from adding six months of hormone therapy to radiotherapy, compared with radiotherapy alone, either in terms of cancer recurrence or survival. 


So, in some patient groups, two years of hormone therapy reduces the risk of the cancer spreading. But hormone therapy is associated with important side effects that can negatively affect patients’ quality of life. These results will help doctors and patients discuss treatment options and take informed decisions about whether having two years of hormone therapy is the right choice for them.  

In Canada, the PR13/RADICALS-RD 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.

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