New study: Local radiotherapy improves the treatment results of metastatic prostate cancer

These findings will benefit thousands of men

– Standard treatment for men newly diagnosed with metastatic prostate cancer is currently drug treatment alone, says Chris Parker (The Royal Marsden NHS Foundation Trust, Sutton, UK), the lead author, who presented the findings of the STAMPEDE study at ESMO2018.

– Although outcomes have improved, men still typically die from metastatic prostate cancer, so there is a need for more effective treatment. We wanted to know if radiotherapy to the prostate might not only improve local control but also slow progression of metastatic disease in men with newly diagnosed, metastatic prostate cancer, says Parker of the background of the study.

2,061 men with newly diagnosed, metastatic prostate cancer were included in the randomised study. Half of the men were only given standard of care treatment (chemotherapy and hormone therapy), and the other half were given local radiotherapy to the prostate, i.e. the site of the primary tumor, in addition to the standard of care treatment. Over a three-year observation period, radiotherapy to the prostate improved survival by a third (32%) in the 819 men with a low burden of metastatic disease. According to the findings of the study, radiotherapy did not improve survival in men with higher metastatic burden.

Radiotherapy to the prostate was also well tolerated in the study. There was a small increase in risk of bladder and bowel side-effects, but, according to the researcher, these were modest.

– The side-effects are certainly outweighed by the survival benefit, says Parker.

The group of researchers recommends that radiotherapy should be introduced as part of the standard treatment also for metastatic prostate cancer

– Until now, it was thought that there was no point in treating the prostate itself if the cancer had already spread because it would be like shutting the stable door after the horse has bolted. However, this study proves the benefit of prostate radiotherapy for these men. Unlike many new drugs for cancer, radiotherapy is a simple, relatively cheap treatment that is readily available in most parts of the world, says Parker.

Based on the findings of the study, the group of researches recommends that radiotherapy should become part of the standard treatment alongside chemotherapy for men with metastatic prostate cancer who have a low burden of metastatic disease. Parker also mentioned that the research findings are also relevant for men with cancer in the lymph nodes of their hips that has not spread elsewhere. In these cases, radiotherapy alongside chemotherapy could be a curative treatment.

At Docrates Cancer Center, local radiotherapy to the prostate is already part of current practice

– This is a significant finding for men with prostate cancer. For the first time, there has been evidence in a study this large and randomised that local radiotherapy to the prostate can improve survival in prostate cancer patients with a low metastatic disease burden. These results should change the standard of care for metastatic prostate cancer, and this will benefit thousands of men around the world. Further research will aim to find out whether this approach could also work for other types of cancer, says Adjunct Professor Timo Joensuu, Chief Physician (Radiotherapy) at Docrates Cancer Center.

– At Docrates Cancer Center, we have been giving local radiotherapy also for patients with metastatic prostate cancer for a long time. We have had excellent results with it. It has been used to, for example, prevent urinary retention and improve prognosis, says Timo Joensuu.

Local high-dose radiotherapy should also help prostate cancer patients with a higher burden of disease

– Even though the STAMPEDE study did not discover benefits related to life expectancy in giving radiotherapy to prostate cancer patients with a higher metastatic burden, i.e. a metastatic prostate cancer that is more aggressive, we can assume that radiotherapy can still be beneficial. However, higher radiation doses and larger radiotherapy volumes would be required in these cases. We have had these kinds of results from Docrates Cancer Center’s non-randomised longitudinal study (ANTICANCER RESEARCH 36: 6439-6448 (2016)) on metastatic prostate cancer, says Timo Joensuu.

The current standard of care treatment does not appear to be effective enough in stopping the progression of metastatic prostate cancer. With standard treatment, the average life expectancy is only about 3.7 years. In the case of more aggressive forms of the disease, the life expectancy may be only a few months. Joensuu is convinced that treatments such as radiotherapy should be used to halt the progress of metastatic prostate cancer.

– We need to treat aggressive forms of prostate cancer more actively, effectively and comprehensively. In Finland, around 900 men die of prostate cancer every year. These research findings could benefit hundreds of men in Finland every year, and thousands of men worldwide, if radiotherapy becomes part of treatment alongside the current standard of care treatment.

The STAMPEDE trial is one of the biggest studies on prostate cancer. The findings of the study were published in The Lancet on 21 October 2018 and were presented at the ESMO (European Society of Medical Oncology) Congress in Munich on the same day.

Sources:

ESMO 2018 Congress. Local radiotherapy improves survival in metastatic prostate cancer with low disease burden [ESMO 2018 Press Release]. https://www.esmo.org/Press-Office/Press-Releases/STAMPEDE-prostate-cancer-radiotherapy-Parker

Radiotherapy to the primary tumour for newly diagnosed, metastatic prostate cancer (STAMPEDE): a randomised controlled phase 3 trial. Christopher C Parker, MD. Prof Nicholas D James, PhD. Christopher D Brawley, MSc. Prof Noel W Clarke, ChM. Alex P Hoyle, MRCS. Adnan Ali, MBBS et al. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(18)32486-3/fulltext

Multimodal Primary Treatment of Metastatic Prostate Cancer with Androgen Deprivation and Radiation. ANTICANCER RESEARCH 36: 6439-6448 (2016). Timo Joensuu et al. http://ar.iiarjournals.org/content/36/12/6439.full.pdf+html

Uusi tutkimustulos tukee aktiivisemman hoidon käyttöä levinneen eturauhassyövän hoidossa. LEHDISTÖTIEDOTE 9.1.2017. Docrates Syöpäsairaala. https://www.docrates.com/uusi-tutkimustulos-tukee-aktiivisemman-hoidon-kayttoa-levinneen-eturauhassyovan-hoidossa