by Delaying treatment for localized prostate cancer does not increase risk of death, new research suggests.
Active surveillance of the disease has the same high survival rates as radiotherapy or surgery after 15 years, according to a new study.
Men who were actively monitored – which includes regular tests to check for the cancer – were more likely to progress or spread than those who received radiation therapy or surgery.
However, this did not reduce their chances of survival, according to the study.
The study also found that the negative effects of radiation therapy and surgery on urinary and sexual function last much longer than previously thought — for up to 12 years.
The researchers suggest the results show that treatment decisions do not need to be rushed after diagnosis of localized low- and intermediate-risk prostate cancer — cancer in the prostate that hasn’t spread to other parts of the body.
The latest results from the ProtecT study, led by the Universities of Oxford and Bristol, were presented at the European Association of Urology (EAU) Congress in Milan and published in the New England Journal of Medicine.
Lead Investigator Professor Freddie Hamdy of the University of Oxford said: “It is clear that, unlike many other types of cancer, a diagnosis of prostate cancer should not be a cause for panic or hasty decisions.
“Patients and physicians can and should take the time to consider the benefits and possible harms of different treatments, knowing that it will not affect their survival.”
The study, the first to fully evaluate three main treatment options – active surveillance, surgery (radical prostatectomy) and radiation therapy with hormones for men with localized prostate cancer, was conducted at nine UK centres.
Between 1999 and 2009, 1,643 men aged 50 to 69 diagnosed with localized prostate cancer were placed into one of three treatment groups.
They were followed for an average of 15 years to measure mortality rates, cancer progression and spread, and the impact of treatments on quality of life.
The study found that about 97% of men diagnosed with prostate cancer survived 15 years after diagnosis, regardless of the treatment they received.
At 15 years, about a quarter of active monitoring patients had not received any invasive treatment.
Men from all three groups reported similar overall quality of life.
The adverse effects of surgery or radiation therapy on urinary, bowel, and sexual function have been found to last much longer than previously thought.
A study published in 2016 found that after 10 years of follow-up, men whose cancer was actively monitored were twice as likely to have it progressed or metastasized than men in the other groups.
While it has been hypothesized that this could result in a lower survival rate for males with active surveillance over a longer period, the 15-year follow-up results show that this is not the case.
Prof Hamdy said: “This is very good news.
“Most men with localized prostate cancer are likely to live a long time, whether or not they receive invasive treatment and whether or not their disease has spread, so a quick decision on treatment is unnecessary and could be harmful.
“It is also now clear that a small group of men with aggressive diseases may not benefit from any of the current treatments, no matter how early they are administered.
“We need to improve both our ability to identify these cases and our ability to treat them.”
Fellow researcher Professor Jenny Donovan of the University of Bristol said: “Now men diagnosed with localized prostate cancer can use their own values and priorities when making the difficult decisions about choosing treatment.”
The researchers say the new study also highlighted flaws in current methods of predicting which prostate cancers are likely to grow and spread quickly.
Initially, all participants in the study were diagnosed with localized cancer and 77% of them were classified as low-risk.
A reassessment using more modern methods showed that a far larger number would now be classified as intermediate risk – and in around 30% of men the disease had already spread beyond the prostate.
This means that the men in the study had a higher grade and stage of disease than originally thought.
Some of the men who later died from their prostate cancer were deemed low-risk when diagnosed, which the researchers say is a cause for concern.
Professor Peter Albers, Chair of the Scientific Congress Bureau of the EAU and a urologist at the University of Düsseldorf, said it was “clear” that not enough was known about the biology of the disease to determine which cancers will be the most aggressive and further research was urgent required is required.
