People who have had post-operative radiotherapy for prostate cancer may not also need hormone therapy
10 Sep 2024
Many people who need radiotherapy after surgery for prostate cancer may be able to avoid having hormone therapy as well.
This is according to the new and final results from the RADICALS-HD clinical trial, which were recently published in European Urology. The trial found no evidence that the addition of hormone therapy improved how long people lived without their cancer spreading, among patients whose doctors considered them suitable for short-term, long-term or no hormone therapy.
Each year, around 7,000 people with localised prostate cancer (which has not spread elsewhere in the body) have surgery to remove their prostate, called a prostatectomy. Around 2,000 of these patients go on to have radiotherapy after the surgery. However, there is debate over whether they should also receive hormone therapy, an important treatment successfully used for more advanced cancers.
The RADICALS-HD clinical trial tested whether giving hormone therapy alongside radiotherapy would benefit people who had already had prostate cancer surgery. They randomised patients receiving radiotherapy after surgery to one of three different groups, who received:
- No hormone therapy
- Six months of hormone therapy (short-term)
- Two years of hormone therapy (long-term).
Doctors and participants could choose to be randomised between all three groups or just two of them. Most participants chose to be randomised between the no hormone therapy and short-term groups or between the short-term and long-term groups. These new results come from those 492 participants who agreed to be randomised between all three groups.
People taking part in this three-way comparison joined between 2007 and 2015. The research team followed them for around 9 years on average.
Overall, participants in this comparison did well and, in those who had died by the time of the analysis, most deaths were attributed to other causes besides prostate cancer.
RADICALS-HD found no meaningful differences in the long-term health outcomes between these three groups, and there was no evidence of an improvement with the addition of either short- or long-term hormone therapy. After 10 years, 80% of participants in the no hormone therapy group were alive without the cancer spreading. This is compared to 77% of those in the short-term group, and 81% of those in the long-term group.
This contrasts with recently-reported results from the two two-way comparisons of the RADICALS-HD trial, which found planning for two years of hormone therapy delayed the spread of cancer when compared to having just six months.
Why is this message a little different? According to the RADICALS-HD team, this may be because people who joined the three-way comparison generally had more favourable disease than those in the long-term vs short-term hormone therapy comparison. This comparison also had a smaller sample size, and there were fewer participants than planned. This meant there were relatively few instances of death or cancer progression in the three-way comparison and it was not statistically powered to detect small differences between the three groups.
The data from this comparison will now be included in the DADSPORT meta-analysis, which will combine data from RADICALS-HD with several other randomised clinical trials. This will provide the best estimate of the benefit from adding hormone therapy to postoperative radiotherapy.
RADICALS-HD demonstrated that people having postoperative radiotherapy after prostate cancer surgery usually do very well and most will live for at least 10 years without their cancer spreading elsewhere in the body. Researchers say that future trials should focus on patients who are at a higher risk of cancer spread and death from prostate cancer.
Following on from RADICALS-HD, a new translational study called RADICALS-TR is being run by Dr Matthew Fittall at UCL Cancer Institute. Their project will analyse specimens from prostatectomy surgeries for which consent for collection was obtained during RADICALS. They aim to identify those patients most likely to experience subsequent cancer relapse. They particularly want to identify those patients most likely to benefit from hormone therapy alongside post-operative radiotherapy. The team hope the findings could translate to stratified clinical trials and better patient care.
The RADICALS-HD trial was funded by the MRC and Cancer Research UK and took place in hospitals throughout the UK, as well as Canada, Denmark and Ireland. The DADSPORT meta-analysis is funded by the UK Medical Research Council.
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