Prostate cancer treatments barely differ on survival, but not on continence and sex

For most men with prostate cancer confined to the gland, the choice between surgery, radiotherapy and active monitoring makes little difference to whether the cancer kills them — but it makes a large difference to continence, erections and bowel function [s1][s2]. In the patient-reported data from the ProtecT trial, surgery did the most lasting harm to urinary control and sexual function, radiotherapy hit the bowel hardest early on, and monitoring let both fade gradually [s1].

That trade-off, not survival, is what a man newly diagnosed with localised disease is actually deciding between, and it is the part often lost in a consultation focused on cutting cancer out.

The trial that isolated the harms

ProtecT recruited from 82,429 men aged 50 to 69 who had a prostate-specific antigen test in the United Kingdom between 1999 and 2009; localised prostate cancer was diagnosed in 2,664 of them, and 1,643 agreed to be randomised — 545 to active monitoring, 553 to radical prostatectomy and 545 to radiotherapy with hormones [s2]. Because the men were assigned by chance rather than by choice, the trial can attribute later differences in function to the treatment itself rather than to who picked what.

Alongside the survival study, the investigators collected patient-reported outcomes: 1,643 men completed validated questionnaires on urinary, bowel and sexual function before diagnosis, at six and 12 months, and annually thereafter, with completion rates above 85 per cent for most measures [s1]. That design — asking the men themselves, repeatedly, over years — is what makes the side-effect data trustworthy rather than an afterthought.

What each treatment did

The patterns were distinct. Of the three options, prostatectomy had the greatest negative effect on both sexual function and urinary continence, and although there was some recovery, those outcomes stayed worse in the surgery group than in the others throughout the trial [s1]. Radiotherapy's biggest hit to sexual function came at six months, after which it recovered somewhat and then held steady, and it had little effect on urinary continence [s1].

The bowel was radiotherapy's distinctive cost: bowel function was worse in that group at six months than in the others and then recovered somewhat, except for an increasing frequency of bloody stools, while it was unchanged in the surgery and monitoring groups [s1]. Urinary voiding and night-time urination were also worse after radiotherapy at six months but mostly recovered by 12 months [s1]. Active monitoring avoided the abrupt drops but was not free: sexual and urinary function declined gradually over the years [s1].

One finding cuts against expectation. Across the three groups there were no significant differences in anxiety, depression, or general or cancer-related quality of life [s1]. The physical functions diverged sharply; the men's overall psychological wellbeing and quality-of-life scores did not.

Why the survival numbers make the harms decisive

The reason these trade-offs carry so much weight is that the survival case for aggressive treatment is weak in this population. At a median of 15 years, death from prostate cancer occurred in 45 of the men, 2.7 per cent overall — 3.1 per cent under active monitoring, 2.2 per cent after prostatectomy and 2.9 per cent after radiotherapy, a spread the trial could not distinguish from chance (P = 0.53) [s2]. Death from any cause, 21.7 per cent, was similar across the groups [s2].

Treatment did reduce the cancer's spread: metastases developed in 9.4 per cent of the monitoring group against 4.7 per cent after surgery and 5.0 per cent after radiotherapy [s2]. But by 15 years, 24.4 per cent of the monitored men were still alive and had never had any prostate-cancer treatment at all — and so had never paid its functional price [s2]. The trial's own conclusion is that with cancer mortality low regardless of choice, the decision comes down to weighing the benefits and harms of each treatment [s2].

For the survival and progression side of that decision, and the case for monitoring low-risk disease, see our account of the ProtecT survival results in full. This piece is about the other half of the ledger: what each path costs in daily function.

What it means for a reader

The practical message is that "treat the cancer" is not one decision but several, each with a different bill. A man weighing surgery is weighing a durable risk to continence and erections; a man weighing radiotherapy is weighing an early bowel and urinary cost that partly recovers; a man weighing monitoring is trading the slow, ordinary decline of function against a modestly higher chance the cancer spreads [s1][s2]. Those costs matter more precisely because, for cancer confined to the gland, the survival stakes between the options are so small [s2].

The functional harms also connect to the rest of men's health. Sexual side-effects overlap with the wider question of low libido and erectile function in men; the diagnostic pathway that now precedes many of these decisions is covered in our piece on MRI before prostate biopsy; and the separate worry about hormones is addressed in testosterone therapy and prostate-cancer risk.

This article is informational and is not medical advice. Treatment decisions for prostate cancer should be made with a clinician who can weigh an individual's tumour and priorities.