Expert busts four major myths about modern radiation therapy for prostate cancer

Long seen as a second-best option or just a solution for recurrent prostate cancer, radiation therapy is equally as successful as surgery —often with fewer side effects. Experts bust some persistent myths about this treatment option, explaining how it can be curative, have fewer side effects than surgery, and who it is suitable (and not suitable) for.

Myth: Radiation therapy is second-best to surgery

“There is a very common misconception broadly that radiation therapy is … this second-grade, last ditch option when surgery is not possible. And this just is not the case,” says Dr Lucinda Morris, a Sydney-based radiation oncologist, researcher and Associate Professor at the University of Newcastle.

Fact: Radiation therapy can cure prostate cancer

Thanks to major advances over the last 10 to 15 years, radiation therapy alone (or sometimes with hormone treatment) can cure prostate cancer, Associate Professor Morris explains. “It’s a highly effective curative treatment with a very favourable toxicity profile.”

Professor Sandra Turner, a radiation oncologist at Sydney’s Westmead Hospital who has treated prostate cancer as her primary specialty for almost 30 years, agrees.

“The evidence from long term follow up of big clinical trials shows the outcomes of radiation therapy versus a surgical approach are equivalent in terms of survival and other cancer outcomes such as development of distant metastases,” she says, citing 12-year and 15-year outcomes from the PROTECT study in the UK.

Medicare recommendations and the Cancer Council’s Optimal care pathway for men with prostate cancer advise encouraging men with potentially curable prostate cancer to discuss their treatment options with both a urologist and a radiation oncologist.

A man must have a prostate cancer diagnosis before they can be referred to a radiation oncologist, Professor Turner says, noting appropriate treatment options will depend on pathology, PSA and other clinical factors. “So we can’t really properly advise a man until we have the biopsy results.”

Some men will need hormone therapy given for a period with radiation therapy to achieve a cure, she adds.

Myth: Radiation therapy is only useful after surgery

“I hear some men being told that they should ‘have surgery as they can have radiation therapy to mop up cancer after surgery but not the other way around’. However, although we do often need to give radiation therapy to treat cancers that are not cured by surgery, and this can be curative, this statement is an over-simplification,” Professor Turner explains. “It is rare that surgery might be needed after radiation therapy and men should not be dissuaded from considering radiation therapy as an option for this reason.”

Fact: Radiation therapy is suitable for most men with potentially curable prostate cancer

Curative treatment with radiation therapy is suitable in almost all cases where active treatment is recommended, regardless of age or local tumour stage, Professor Turner says.

It is also suitable for men who can’t have surgery—and can be preferable to surgery for various reasons.

“It’s so much less invasive, doesn’t involve admission to hospital, doesn’t involve a major operation, or a long anaesthetic,” Professor Turner explains.

“Radiation therapy is given as an outpatient. Men can drive to their appointments. And just the convenience of that, and the lack of needing recovery in terms of driving or working, is one major advantage of radiation therapy—and one reason that many working men actually choose to have that treatment, because it’s less intrusive on their life.”

Depending on pathology and other factors, a cancer contained within the prostate usually needs between five and 20 treatments, she says.

Radiation therapy also has an important role as adjuvant treatment after surgery and in palliation to treat distant metastases, she adds, noting it is “a very effective way of alleviating bone pain. Many men with metastases are still going to live a long time.”

What about radiation if cancer recurs after surgery?

Associate Professor Morris says men are often told that ‘if you have the surgery and it fails, you’ve always got the radiotherapy up your sleeve, but if you have the radiotherapy up front, you’re not going to have the option of surgery.’

However, urologists that are experienced in doing radical prostatectomy will be able to remove it after the radiation,” she says.

“It’s a harder operation and you’re more likely to cause incontinence, but actually it can be done.”

Cancer recurrence after radical prostatectomy is “quite common,” particularly for the higher-grade lesions, Professor Turner says, and radiation therapy is often used to treat the prostate bed in this case.

This is not ideal, however, “because although we can often cure men, we are putting the potential side effects of radiation therapy on top of the problems with surgery. And if somebody’s had surgery – already had some injury to the sphincter and some erectile problems – those problems are worsened by radiation therapy.”

In fact, if there’s reason to believe a man might need radiation therapy after surgery, “we would usually strongly advise them to avoid the operation and have the radiation therapy, often with some hormones, up front,” Professor Turner says, noting it can reduce the likelihood of recurrence.

This is because they can treat a few millimetres of tissue around the prostate, reducing the chance of leaving cancer cells behind.

“So it’s unlikely that the cancer would come back just outside the prostate if radiation therapy is given. And these days where we can really escalate the dose, it’s becoming much less common for the cancer to come back in the prostate itself.”

Who is radiation therapy NOT recommended for?

It’s not for everyone, though, and is not generally recommended for:

• Men with low-risk prostate cancers (i.e. PSA < 10, Gleason score 3+3=6 or grade group 1). “We would suggest these men go on active surveillance,” Professor Turner says. “They shouldn’t have surgery either.”
• Men who are unlikely to live more than 8-10 years, “particularly if they don’t have a nasty-looking cancer.” Similarly, these men will not be suitable for surgery.
• Men with a very large gland and severe lower urinary tract symptoms, who often need surgery to remove obstructions and typically don’t do well with radiation therapy, she says.

Myth: Radiation therapy always damages surrounding tissues

Associate Professor Morris says radiation therapy is sometimes still perceived as “very dangerous and difficult,” but contemporary treatment is very different to what it was a decade ago.

Fact: Radiation therapy is more precise than ever

“We are able to treat these prostate cancers with millimetre accuracy,” she says, explaining that imaging advances have significantly improved the ability to “deliver extremely high doses to the cancer and to the prostate, but reduce dose to the healthy organs around the prostate—like the bladder and the rectum.”

“It is honestly like comparing a smartphone to a walkie-talkie in terms of the technology,” she says.

Professor Turner stresses this not only increases the chance of a cure, it also lowers risk to surrounding organs—and radiation oncologists can now perform a “mini procedure” before treatment to further improve safety margins.

This involves inserting small gold markers into the prostate to make it easier to see on imaging and adjust treatment if it moves, as well as injecting a water-based gel between the prostate and anterior rectal wall, which physically pushes the prostate away from the rectal wall. Even higher radiation doses have minimal to no impact on the rectal wall, and the gel dissolves in the months after radiation is delivered, so the anatomy returns to normal, Professor Turner explains.

As a result, radiation proctitis is now rare, she says. “I quote 5% risk of having bleeding, which typically peaks at a year to 18 months. And often that bleeding doesn’t need any treatment.”

“They just need a colonoscopy to check it’s not coming from a more serious cause such as rectal cancer. Only occasionally now do patients need Argon laser therapy to treat telangiectasia.”

How do the side effects compare?

As with all treatments, radiation therapy has side effects. Uncommon long-term side effects can include (usually) mild changes in bowel habit and erectile dysfunction. However, Professor Turner says the PROTECT trial showed that radiation therapy caused less problems with incontinence and impotence than surgery did.

“At 15 years, erectile function and continence (reported by men) were better for radiation therapy vs surgery — and rectal problems were worse. However, the rectal side effects have dramatically reduced due to technology and spacers (the gel) since the PROTECT study was done,” she explains.

Incontinence is rare with radiation therapy, but quite common with surgery, she notes.

While all treatments for prostate cancer can impact sexual function, tighter radiation fields help reduce dosage to important nerve bundles, she adds.

“In men that have good erections and what they’d regard as normal sexual function, particularly if they’re in the younger age group, maybe 50s, 60s, early 70s, it’s common that men return to normal erectile function and sexual enjoyment.”

Practice tip

GPs should follow up any unusual rectal bleeding after treatment and warn patients it’s slightly more likely that blood will be detected on faecal occult blood testing, Professor Turner says.

Myth: Radiotherapy is not for younger men due to the secondary cancer risk

Associate Professor Morris says this is often cited as a reason why men in their 50s or 60s should not have radiation therapy, but it should not hold a man back from considering this option.

Fact: Secondary cancer risk is just one part of the big picture

It’s “very uncommon” for a man to develop a second malignancy due to radiation therapy for prostate cancer, and the risk is frequently overstated to patients, says Associate Professor Morris.

Professor Turner notes prevalence estimates vary, and it’s difficult to show a cause-and-effect relationship because tissues affected by radiation—like the bladder and rectum––are common sites for cancer anyway.

“The worst possible estimate that I’ve seen is that one in a hundred men over a 10-year period may get a second cancer from their radiation therapy,” she says.

This needs to be weighed up against the odds of experiencing a major issue after a radical prostatectomy, which are also about one in a hundred, she adds.

“There are serious rare risks with all treatments for cancer. And you might argue that you’d rather be on the lookout for a second cancer versus the same risk of having major operative or perioperative complications.”

Key takeaways:

• Radiation therapy alone (or with temporary hormone therapy) can cure prostate cancer.
• It is almost always an option for men in whom radical treatment for their prostate cancer is recommended
• Radiation therapy is safer and more effective with fewer side effects than ever before.
• Men should be advised to see both a urologist and a radiation oncologist to help them make an informed treatment decision.

More information
Targeting Cancer | Developed by RANZCR’s Faculty of Radiation Oncology, this website has a GP portal with information about indications for radiotherapy, side effects, treatment centres, and how to refer.

This article was based on a podcast that Professor Turner and Associate Professor Morris recorded with Dr David Lim. You can listen to the full episode here.