Large prostate Ca study evaluates RP, radiation, monitoring

Nearly 100% of patients with clinically localized prostate cancer, detected by PSA testing, survive at an average 10 years’ follow-up, regardless of whether they had active monitoring, radical prostatectomy, or radiotherapy, according to results from the ProtecT study.

The authors report that while there were no significant differences in survival among treatment groups, patients who had surgery and radiotherapy had lower incidences of disease progression and metastases but higher risk of side effects compared to those on active monitoring.

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These are among the first results of the United Kingdom’s largest trial to date looking at prostate cancer treatment, and the first time radiotherapy, surgery, and active monitoring treatments for prostate cancer have been compared directly, according to a press release from the UK’s National Institute for Health Research. The findings were published online in the New England Journal of Medicine (Sept. 14, 2016).

An expert who discussed the findings with Urology Times said the research needs to continue longer in order to see survival benefit in patients undergoing definitive treatment.

The authors studied 82,429 men between 1999 and 2009. Study subjects were 50 to 69 years of age and had received a PSA test. Of the 2,664 who were diagnosed with localized prostate cancer, 1,643 agreed to be randomized to active monitoring (545 men), surgery (553), or radiotherapy (545). There were no notable differences among the groups at baseline. The men had a median PSA level of 4.6 ng/mL and 77% had tumors with a Gleason score of 6. Slightly more than three-fourths of the men had stage T1c disease.

The study’s chief investigator, Freddie Hamdy, MD, FMedSci, of the University of Oxford, Oxford, United Kingdom, told Urology Times that important takeaways from the study are not only that 99% of patients survive at an average of 10 years’ follow-up irrespective of treatment assigned, but also that radical treatment is effective in reducing the risk of metastases and disease progression in these patients.

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Another key finding: Radiotherapy and radical prostatectomy are equally effective treatment options.

While disease spread was reduced by half in men who were assigned to radical treatment, there was no difference in survival outcomes with either surgery or radiotherapy and no progression of the disease in three-fourths of the men in the active monitoring treatment group during the decade-long study, according to the release.

“Men who stay on active monitoring avoid side effects of active treatments, but treatment reduces the risk of disease progression,” Dr. Hamdy said.

Next: Companion paper reports on radical treamtment disadvantages

A companion paper(N Engl J Med Sept. 14, 2016 [epub ahead of print]), by co-researcher Jenny L. Donovan, PhD, PhD(Lond), FMedSci, of the University of Bristol, Bristol, United Kingdom, and colleagues, reports the unpleasant side effects associated with radical treatments include urinary leakage and sexual dysfunction, which occur mainly with surgery. While some of the men who underwent radical treatments recovered from associated side effects in 2 to 3 years, researchers found that after 6 years, twice as many men in the surgery group continued to experienced urine leakage and problems with their sex lives, compared to men in the active monitoring and radiotherapy groups. Radiotherapy caused more bowel problems than surgery or active monitoring.

“General quality of life, anxiety, and depression measures appear the same irrespective of treatment assigned,” according to Dr. Hamdy.

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Dr. Hamdy said these results have impacted his practice.

“I have now more real information about short- and long-term side effects of treatment options, against the backdrop of benefits in reducing metastases and disease progression, which will help patients to decide on their treatment,” Dr. Hamdy said. “I can tell men that their risk of dying from prostate cancer is very low-at around 1% over 10 years. I can also tell them that surgery and radiotherapy are equally effective.”

In fact, Dr. Hamdy said he was surprised by the very low disease-specific (1%) and all-cause mortality rates (10%), which are much lower than that seen in all other randomized studies. It was also an interesting finding that some men with apparently low-risk disease died of prostate cancer, he said.

It’s important for the urology community to glean from the findings that disease can progress slowly over 10 years, 80% of patients have no sign of progression, and the difference in reduction of metastases has not translated into survival benefits.

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“This may change over a longer period of follow-up, but we do not know yet,” Dr. Hamdy said.

Urology Times Editorial Consultant J. Brantley Thrasher, MD, of the University of Kansas Medical Center, Kansas City, said the study’s findings come as no surprise to him.

“The fastest growing patient population in my practice is active surveillance for those with low-grade localized prostate cancer,” Dr. Thrasher said. “Prostate cancer has such a slow growth rate that I think that we will need to extend the study longer to see the survival benefit for those who undergo definitive treatment. With the difference seen in rates of spread, I suspect that with longer follow-up, a cancer-specific survival difference will become evident.”

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