• This study provides important information for patients newly diagnosed with prostate cancer. (Getty Images)Source: Getty Images
Radiation for prostate cancer could increase your risk of developing a secondary cancer years after treatment by up to four per cent, experts warn.
By
Yasmin Noone

3 Mar 2016 - 12:07 PM  UPDATED 3 Mar 2016 - 1:56 PM

Radiotherapy is a common cancer treatment but new research has highlighted the risk for prostate cancer patients using the medical treatment.

A new study, published in The BMJtoday, has discovered an association between radiotherapy for the treatment of prostate cancer and a slightly higher risk of developing secondary cancers of the bladder, colorectal tract, and rectum.

The scientists based at University of Toronto, assessed 21 studies to determine the risk of secondary malignancies in patients, mostly aged in their 60s or early 70s, five to 10 years after treatment.

They found the risk of developing a secondary cancer increased up to four percent for patients who received radiotherapy for prostate cancer.

“For many years, there was concern regarding the risk of secondary cancers following radiotherapy for prostate cancer but there was no conclusive evidence,” says the study’s lead author, Ajmera Family Chair in Urologic Oncology and Professor of Surgery at University of Toronto, Dr Richard Nam.

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“This study provides important information for patients newly diagnosed with prostate cancer…It shows consistent evidence of an increased risk of bladder, rectal and colorectal cancers.”

Prof Nam says even though the overall absolute risk of the cancer spreading is still very low for this treatment, doctors should share the information with patients during radiology treatments, especially if the patient has a long life expectancy of 20-plus years and if the radiation has a 50/50 (or lower) chance of success.

“This information should be considered for men with newly diagnosed prostate cancer when deciding on which treatment to undergo,” he says.

“For patients with intermediate or high-risk disease who require active treatment, the risk of secondary cancers must be weighed against the burden of treatment and of other complications when deciding between treatment with radiotherapy or surgery.”

This information should be considered for men with newly diagnosed prostate cancer when deciding on which treatment to undergo.

Two US experts from the Harvard Radiation Oncology Program and Massachusetts General Hospital have also urged that this new information be included in consent forms for radiation treatment.

“[This study] confirms our belief that second malignancy should be added to the already long list of avoidable hazards associated with treatment for those men with low risk prostate cancer who simply need no treatment at all,” the experts write in an editorial accompanying the study.

According to Cancer Council Australia, 20,065 new cases of prostate cancer were diagnosed in Australia in 2012. More than 3,110 men died from prostate cancer nationwide in 2013.

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Scientific writer at the Prostate Cancer Foundation of Australia, Dr Wendy Winnall, explains that although the research findings are accurate, radiotherapy techniques have improved since the patients studied were initially treated.

That’s why, she says, the increase in secondary malignancies seen in the patients from many years ago are not necessarily indicative of the side-effects from the newest radiotherapy techniques available today.  

“Newer treatments such as intensity-modulated radiotherapy, image-guided radiotherapy and conformational EBRT have increased the effectiveness and reduced the side-effects from radiotherapy,” says Dr Winnall.  

Every treatment option for patients with a diagnosis of prostate cancer is associated with side effects including urinary incontinence and erectile dysfunction. Treatment for a secondary cancer often carries a risk of serious complications.

People with prostate cancers should not be dissuaded from seeking radiotherapy based on this study

But Dr Winnall insists the risk of developing a second malignancy should never prevent a patient from receiving treatment.

“People with prostate cancers should not be dissuaded from seeking radiotherapy based on this study.

“Balancing the benefits and risks will depend on the individual needs and medical background of each patient.

“The Prostate Cancer Foundation of Australia recommends that those diagnosed with this disease discuss the potential benefits and side effects of each treatment option with their healthcare team, in order to make an informed choice about their treatment pathway.”

More research is needed to conclusively determine a cause and effect relationship between prostate cancer treatment side effects and other cancers.