Clinical studies show that delaying treatment for localized prostate cancer does not increase the risk of death.
Active surveillance of prostate cancer has the same high 15-year survival rates as radiation therapy or surgery, reports the largest study of its kind.
The latest results of the ProtecT study, led by the Universities of Oxford and Bristol, were presented on March 11 at the European Association of Urology (EAU) Congress in Milan and published in New England Journal of Medicine.
The study was funded by the National Institute for Health and Care Research (NIHR).
Although men under active surveillance — which includes regular tests to check for the cancer — were more likely to see progression or spread than those who received radiation therapy or surgery, it didn’t reduce their chances of survival.
The study also found that the negative effects of radiation therapy and surgery on urinary and sexual function last much longer than previously thought — up to 12 years.
The results show that treatment decisions should not be rushed after diagnosis of low- and intermediate-risk localized prostate cancer, according to lead investigator Professor Freddie Hamdy of the University of Oxford.
“It is clear that a diagnosis of prostate cancer, unlike many other types of cancer, should not be a cause for panic or hasty decisions,” he said. “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 was conducted in nine UK centers and is the longest-running study of its kind. It is 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.
Between 1999 and 2009, 1,643 men aged 50 to 69 in the UK diagnosed with localized prostate cancer following a PSA blood test consented to randomized active surveillance (545), radical prostatectomy (553) or radical radiotherapy (545) to ). The research team followed the men for an average of 15 years to measure mortality rates, cancer progression and spread, and the impact of treatments on quality of life.
They found that about 97% of men diagnosed with prostate cancer survived 15 years after diagnosis, regardless of the treatment they received. About a quarter of the men under active surveillance had not received invasive treatment for their cancer after 15 years.
Patients from all three groups reported similar overall quality of life in terms of their general mental and physical health. However, it has been found that the negative effects of surgery or radiation therapy on urinary, bowel and sexual function last much longer than previously thought.
In previous findings published in 2016, the researchers 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. The assumption was that this could lead to a lower survival rate for males with active surveillance over a longer period of time. However, the results of the 15-year follow-up show that this is not the case and that survival rates remain similarly high in all groups.
Professor Freddie Hamdy said: “This is very good news. Most men with localized prostate cancer are likely to live long lives, 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.”
Co-researcher Professor Jenny Donovan of the University of Bristol said: “Patients and doctors now have the information they need about the long-lasting side effects of treatments to better understand the trade-offs between benefits and harms. Survival no longer has to be taken into account when making therapy decisions – because that is the same for all three options. Now men diagnosed with localized prostate cancer can use their own values and priorities when making the difficult decisions about choosing treatment.”
The study also highlighted shortcomings in current methods for predicting which types of prostate cancer are likely to grow and spread rapidly. First, all of the people recruited for 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 greater number of them are now classified as intermediate risk – and in around 30% of men the disease had already spread beyond the prostate. This means that study participants had a higher grade and stage of disease than originally thought. Despite this finding, mortality was still low even when men with intermediate disease received delayed or no radical treatment. Some of the men who later died from their prostate cancer were deemed low-risk when diagnosed, which the researchers highlight as worrisome.
Professor Peter Albers, Chair of the Scientific Congress Bureau of the EAU and Urologist at the University of Düsseldorf, said: “The fact that the greater progression of the disease observed under active surveillance did not result in higher mortality will both surprise and encourage urologists and patients. Active surveillance and biopsy protocols are much more advanced today than when this study was conducted, so we may be able to improve these results even further. It’s an important message for patients that delaying treatment is safe, especially since it also means delaying side effects.”
“But it’s also clear that we still don’t know enough about the biology of this disease to determine which cancers will be the most aggressive, and more research on this is urgently needed.”
Reference: “Fifteen-Year Outcomes After Surveillance, Surgery, or Radiation Therapy for Prostate Cancer” by Freddie C. Hamdy, FRCS(Urol.), F.Med.Sci., Jenny L. Donovan, Ph.D., F.Med. Sci., J. Athene Lane, Ph.D., Chris Metcalfe, Ph.D., Michael Davis, M.Sc., Emma L. Turner, Ph.D., Richard M. Martin, BM, BS, Ph . D., Grace J. Young, M.Sc., Eleanor I. Walsh, M.Sc., Richard J. Bryant, Ph.D., FRCS(Urol.), Prasad Bollina, MB, BS, FRCS(Urol . ), Andrew Doble, FRCS(Urol.), Alan Doherty, FRCS(Urol.), David Gillatt, FRCS(Urol.), Vincent Gnanapragasam, Ph.D., FRCS(Urol.), Owen Hughes, FRCS(Urol . ), DM, Roger Kockelbergh, DM, FRCS(Urol.), Howard Kynaston, MD, FRCS(Urol.), Alan Paul, MD, FRCS(Urol.), Edgar Paez, FRCS(Urol.), Philip Powell, MD , FRCS, Derek J. Rosario, MD, FRCS(Urol.), Edward Rowe, MD, FRCS(Urol.), Malcolm Mason, MD, FRCR, James WF Catto, Ph.D., FRCS(Urol.), Tim J. Peters, Ph.D., F.Med.Sci., Jon Oxley, MD, FRCPath., Naomi J. Williams, Ph.D., John Staffurth, FRCR, FRCP, and David E. Ne al, F.Med.Sci. for the ProtecT Study Group, March 11, 2023, New England Journal of Medicine.
Meeting: EAU23 Annual Congress of the European Society of Urology
Funding: National Institute for Health Research