The content of this website is intended for healthcare professionals only

Radiotherapy implants boost chances of prostate cancer remission

Patients twice as likely to be disease free after five years as those given external radiation alone

Caroline White

Monday, 27 April 2015

Men with prostate cancer given permanent radiotherapy implants (brachytherapy) were twice as likely to be disease-free five years later as those treated with external radiation, indicate the results of a randomised controlled trial* (ASCENDE-RT).

The preliminary findings were presented at the European Society for Radiotherapy and Oncology (ESTRO) 3rd Forum in Barcelona, Spain, today.

The trial included 398 men with cancer that had not spread outside the prostate gland, but who were at high risk of treatment failure, based on standard tests for several features of the cancer.

The men were initially treated with androgen deprivation therapy (ADT), aimed at reducing levels of the male hormones that fuel prostate cancer cell growth. After eight months of treatment, they received 46 Gy of external beam radiotherapy to the prostate and regional lymph nodes.

Subsequently, 198 men were given low-dose-rate prostate brachytherapy (LDR-PB) in which tiny radioactive seeds are implanted in the prostate gland under general or spinal anaesthesia. The other 200 patients were randomly assigned to dose-escalated external beam radiation therapy (DE-EBRT) and were given an additional 32 Gy of external beam radiation to achieve a total prostate dose of 78 Gy.

“At five years’ follow up, we saw a large advantage in progression-free survival in the [brachytherapy] group,” commented Professor James Morris, from the Department of Radiation Oncology, Vancouver Cancer Centre, British Columbia Cancer Agency.

“Although, to date, overall survival and prostate cancer-specific survival do not appear to differ between the two groups, existing trends favour LDR-PB, and an overall survival advantage is likely to emerge with longer follow-up.”

Brachytherapy is extremely cost effective, say the researchers, but it does require prolonged training and experience to produce consistent results, and this may limit more widespread adoption.

An additional problem is that, in the trial, the LDR-PB patients experienced more urinary side effects than those given DE-EBRT.

In a separate presentation**, Professor Morris’s Clinical Research Fellow, Dr Sree Rodda, told the conference that the incidence of severe late urinary side effects was three times higher in patients who received LDR-PB than in those who had DE-EBRT.

“Many of these severe adverse effects were temporary and reversible, or could be ameliorated by procedures. Moreover, more than 80% of patients in the LDR-PB arm had few or no long-term urinary side effects,” he explained.

“However the long-term prevalence of severe urinary toxicity in the LDR-PB patients was 8% compared to just 2% for the DE-EBRT patients. An important challenge for the future will be the reduction of these adverse effects while maintaining the advantages of LDR-PB,” he suggested.

Professor Philip Poortmans, President of ESTRO, commented: “Brachytherapy is an extremely efficient and safe radiation oncology modality, and this trial shows that it can have a wider field of applicability than simply in very localised and low risk tumours when combined with other techniques - in this case, androgen deprivation therapy and external beam radiation therapy.”

* Abstract PD-0047 GU and GI toxicity in ASCENDE-RT: A Multicentre Randomized Trial of Dose-Escalated Radiation for Prostate Cancer

** Abstract OC-0485: LDR Brachytherapy is Superior to 78 Gy of EBRT for Unfavourable Risk Prostate Cancer: The Results of a Randomized Trial

Registered in England and Wales. Reg No. 2530185. c/o Wilmington plc, 5th Floor, 10 Whitechapel High Street, London E1 8QS. Reg No. 30158470