Cancer specialists are bracing themselves for publication of a research study that will challenge the way one of the commonest cancers is treated. The world's biggest randomised trial of prostate cancer has found that the standard surgical treatment for the disease is ineffective.

The study compared surgical removal of the prostate gland – radical prostatectomy – with "watchful waiting" (doing nothing). The results show that surgery did not extend life. A leading British specialist, who asked not to be named, said: "The only rational response to these results is, when presented with a patient with prostate cancer, to do nothing."

Cancer of the prostate is the commonest male cancer affecting 37,000 men a year in the UK and causing 10,000 deaths.

But in up to 50 per cent of cases it is slow-growing so that patients affected, even when left untreated, can live for many years and die of something else.

Some specialists are beginning to question whether these cases qualify for the label "cancer" at all.

The results of the Prostate Intervention Versus Observation Trial (PIVOT), led by Timothy Wilt and started in 1994 with 731 men, showed that those who underwent the operation had less than a three per cent survival benefit compared with those who had no treatment, after being followed up for 12 years. The difference was not statistically significant and could have arisen by chance.

When the findings were presented at a meeting of the European Association of Urology in Paris in February, attended by 11,000 specialists from around the world, they were greeted with a stunned silence.

One expert who attended the meeting said that while most research results are immediately transmitted by specialists in the audience using social media, "I did not see any urologists enthusiastically tweeting about [this one]."

Prostate cancers are already classified as "tigers" (aggressive) or "pussy cats" (low risk). But some urologists who have spent years training to perform complex surgical techniques find the idea of watchful waiting unacceptable.

Surgery carries a risk of side effects that can have a serious impact on quality of life with 50 per cent of men suffering impotence and 10 per cent incontinence.

Ben Challacombe, consultant urologist at Guys and St Thomas' NHS Trust, disagreed with the analysis that the response should be to do nothing. Many of the men in the trial were older, with an average age of 67, low risk and would not have been offered surgery in the UK.

"We would offer milder treatment such as radiotherapy or watchful waiting. We are better than the US in putting men on surveillance," he said.

The controversy over the best treatment for prostate cancer has split professional opinion. Some specialists claim treatment is at the stage where breast cancer was a generation ago when the only surgical treatment was mastectomy, removal of the whole breast.

Today most women with breast cancer are treated with lumpectomy, involving surgical removal of the tumour, leaving the rest of the breast intact. Urologists believe a similar approach in prostate cancer could improve survival and reduce the risk of side effects because a smaller proportion of the prostate gland would be targeted and surrounding tissue left unaffected.

Critics of the approach say there is not enough evidence to justify targeted therapy. Joel Nelson, of the department of urology at the University of Pittsburgh, said prostate cancer triggers molecular changes in the whole of the gland, which can lead to "malignant transformation".

Targeting only part of the gland gives a "false sense of security", when there is a risk of recurrence which could be harder to treat, Mr Nelson said. There are no clear criteria of success which could lead to "technical incompetence".

Dr Kate Holmes, head of research at The Prostate Cancer Charity, said: "Early data from the PIVOT trial certainly suggests that surgery to remove the prostate does not provide any significant survival benefit for men with low to medium risk prostate cancer. However, these findings are from a large ongoing trial, and we look forward to seeing the full published results which could help men in future to make more informed decisions about treatment. "

Facts

37,000 The number of British men newly diagnosed with prostate cancer every year

50% The rise in the number of men diagnosed with the condition in the last 20 years

10,000 The number of British men who die from prostate cancer each year

70% The proportion of men with prostate cancer who survive for at least five years