ProtecT and survival: what do we make of major prostate cancer trial?

Simon Crompton

Simon Crompton

It’s a study worthy of headlines, and it got them. The early results of the ProtecT trial have been published – and they’re important if only because this is the first randomised study comparing three common approaches to localised prostate cancer: surgery, radiotherapy and active surveillance.

The news stories have been clear on the main finding of the trial: “Monitoring of prostate cancer as effective as treatment”; “Prostate cancer patients live just as long with no treatment, experts have revealed”. The stories followed the upbeat lead of press releases from the researchers’ own institutions, the universities of Bristol and Oxford: “Active monitoring is as effective as surgery and radiotherapy, in terms of survival at 10 years, reports the largest study of its kind,” they said.

The researchers found that around 1% of the 1,643 men with localised prostate cancer had died after ten years, regardless of whether they had undergone a prostatectomy, radiotherapy or a programme of regular testing to check for progression (active surveillance). And those on active surveillance had the added benefit of avoiding the severe side effects that can result from treatment. Positive about the benefits of monitoring over intervention, then.

Increased risk of metastasis

But if you’d read the editorial in the New England Journal of Medicine accompanying the study’s publication, you might believe you were reading about entirely different research. This focused on the finding that, although similar numbers in each group survived at ten years, those in the active surveillance group were more than twice as likely to have metastases and disease progression.

To the editorial author, radiation oncologist Anthony V D’Amico, an increased risk of metastasis in active surveillance was the most significant conclusion to be drawn from the research.

“Therefore, if a man wishes  to avoid metastatic prostate cancer and the side effects of its treatment,” he wrote, “monitoring should be considered only if he has life-shortening coexisting disease such that his life expectancy is less than the 10-year median follow-up of the current study.”

No definitive conclusions

The fact is that, though important, these results are still too limited for anyone to be able to draw definitive conclusions about the merits of active surveillance. If anything, they seem to have further polarised the stances of those set on opposite sides in the prostate cancer overtreatment debate.

So next, to move on, we need to see what happens beyond 10 years in terms of mortality. And we need a more stratified breakdown of what happened to men with different Gleason scores (indicators of cancer aggression). The men included in the active surveillance group in this study had higher Gleason scores than would normally be eligible for active surveillance – so the overall results may not reflect this approach accurately.

The headlines, of course, never reveal the full story.

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