Despite advances in radiation treatment for prostate cancer, an established technique, it can reoccur in some patients most often within the prostate gland itself.
Localized recurrence is treatable and in many cases curative, however there is no consensus on the best option.
According to the research, more patients who had low-dose-rate (LDR) brachytherapy had side effects compared to high-dose-rate (HDR) brachytherapy and external beam radiotherapy (EBRT).
In LDR brachytherapy, doctors implant permanent low dose radioactive seeds in the prostate which remain in place but can sometimes move.
HDR brachytherapy, uses high-activity radiation sources that are temporarily placed within applicators inserted within the prostate, typically over 1-3 treatment sessions. The applicators are removed after each treatment with nothing left inside the patient. Both types of brachytherapy require a general anesthetic.
EBRT delivers a high dose of radiation, with the aid of high precision computers, to the tumor while sparing the healthy tissue around it.
It is the least invasive radiation treatment and the patient does not require a general anesthetic. With advances in this type of radiation treatment, EBRT can now be delivered to men with prostate cancer in 5 treatment sessions usually over the course of 2 weeks.
Short term side effects of treatment may affect both the urinary system and gastrointestinal system including pain, bleeding, frequency and urgency.
In the longer term, treatment may cause urethral strictures, a narrowing of part, or all of the tube that carries urine outside the body from the bladder.
The review found that in both the short and long term, LDR brachytherapy was associated with a much higher frequency of urinary and gastrointestinal problems than HDR brachytherapy and EBRT.
Few if any patients in the review who received HDR brachytherapy experienced gastro-intestinal problems and the numbers for EBRT were similarly low.
Co-author Professor Ananya Choudhury, is Chair in Clinical Oncology at The University of Manchester and Honorary consultant Clinical Oncologist at The Christie NHS Foundation Trust.
She said: “In the UK, prostate cancer is the most common cancer in men. Although radiotherapy is very effective, it can recur in around 15% of cases within 5 years of the treatment. There is currently no consensus on how best to treat reoccurrence.
“However, we do know that another course of radiotherapy, called reirradiation, may be better than other options such as surgery as there are fewer side effects.
“But although it may be safer than surgery, radiotherapy can still cause bowel and urinary problems.
“Though much more work needs to be done, this study begins to show that side effects can be reduced if clinicians choose the right therapy based on the evidence.”
Dr. Jim Zhong, a Clinical Research Fellow at the University of Leeds said: “Our systematic review found that HDR brachytherapy or external beam radiation appeared to best balance how well the cancer was controlled along with fewer side effects. This also mirrors what happens in first time diagnosis.
“But it also highlights the need for further high quality prospective and randomized research studies to measure the efficacy and side effects associated with prostate reirradiation.
“Studies will need to place more emphasis on the importance of looking at how such treatments impact the patient’s self-reported quality of life.
“A major limitation of the existing literature is that it is based on what clinicians think not what patients report—only a third of the 39 studies included patient reported symptoms.
“And some studies in the review were carried out 20 years ago, when radiotherapy was not as effective.”