A form of radiotherapy targeting the pelvis is safe for men with advanced localised prostate cancer, according to a new study.
In a trial part-funded by Cancer Research UK, patients who received the smallest dose of intensity modulated radiotherapy (IMRT) targeting lymph nodes in the pelvis had the lowest levels of bowel or bladder side effects compared to patients who had the highest doses. 
IMRT bends the radiotherapy beam to fit the tumour or target tissue, allowing cancer cells to receive a higher dose while reducing the dose to surrounding tissue. 
The trial’s leader, Professor David Dearnaley, an expert in prostate cancer at the Institute of Cancer Research, London (ICR) and consultant clinical oncologist at The Royal Marsden NHS Foundation Trust, said the trial was one of the first to test the safety of this type of IMRT at different doses for prostate cancer.
“These long-term results demonstrate that using IMRT to target the pelvic lymph nodes is safe and effective for men with prostate cancer,” he said. “This technique has already proven to be a game changer for men with prostate cancer.”
The trial, published in the International Journal of Radiation Oncology Biology Physics, included 447 men who received one of 3 doses of IMRT targeting the pelvic lymph nodes, alongside IMRT targeting the prostate and standard hormone therapy. They were followed up for more than seven years on average.
Giving radiotherapy to the area around a prostate tumour is risky due to the damage that can be done to the bowel.
Patients who received the lowest dose of IMRT to the pelvic lymph nodes had fewest side effects – around eight in 100 had bowel complications and around four in 100 had bladder complications. 
But among those who had the lowest dose of IMRT to the pelvis, 38 in 100 patients were alive without a relapse after five years, compared to an average of 71 in 100 across the whole study.