Patients with prostate cancer who undergo active monitoring may experience the same 15-year survival rates as those who undergo radiotherapy or surgery, according to new findings published by Hamdy et al in The New England Journal of Medicine and simultaneously presented at the 2023 European Association of Urology Annual Congress.
Although patients on active monitoring were more likely to see their cancer progress or metastasize than those receiving radiotherapy or surgery, this may not reduce their likelihood of survival. Researchers also found that the negative impacts of radiotherapy and surgery on urinary and sexual function may persist up to 12 years—much longer than previously thought.
Background
“It’s clear that, unlike many other cancers, a diagnosis of prostate cancer should not be a cause for panic or rushed decision-making,” stressed lead study author Freddie Hamdy, MBChB, MD, FRCS (Urol), FMedSci, the Nuffield Professor of Surgery and Professor of Urology in the Nuffield Department of Surgical Sciences at the University of Oxford. “Patients and clinicians can and should take their time to weigh up the benefits and possible harms of different treatments in the knowledge that this will not adversely affect their survival,” he added.
Study Methods and Results
In the new Prostate Testing for Cancer and Treatment (ProtecT) trial, the researchers randomly assigned 1,643 patients aged 50 to 69 years—who were diagnosed with localized prostate cancer after a prostate-specific antigen blood test—to undergo active monitoring (n = 545), radical prostatectomy (n = 553), or radical radiotherapy (n = 545). The researchers followed the patients for an average of 15 years to measure mortality rates, cancer progression and metastasis, and the impact of treatments on their quality of life.
They found that around 97% of the patients diagnosed with prostate cancer survived 15 years after diagnosis, irrespective of which treatments they received. Additionally, about 25% of those on active monitoring had still not undergone any invasive treatments for their prostate cancer after 15 years of follow-up.
Patients from all three groups reported experiencing a similar overall quality of life—representing their general mental and physical health—but the negative effects of surgery or radiotherapy on urinary, bowel, and sexual function were found to persist much longer than previously thought.
In earlier findings from 2016, the researchers found that after 10 years of follow-up, patients whose cancer was actively monitored were twice as likely to see it progress or metastasize than those in the other groups. The assumption had been that this might lead to a lower survival rate for those on active monitoring over a longer time. However, the results at 15 years have shown that survival rates may remain similarly high across all groups.
The new findings demonstrated that treatment decisions following diagnosis in patients with low- and intermediate-risk localized prostate cancer potentially do not need to be rushed.
Study Implications
“This is very good news. Most [patients] with localized prostate cancer are likely to live for a long time, whether or not they receive invasive treatment and whether or not their disease has [metastasized]—so a quick decision for treatment is not necessary and could cause harm,” underscored Dr. Hamdy. “It’s also now clear that a small group of [patients] with aggressive disease are unable to benefit from any of the current treatments, however early these are given. We need to both improve our ability to identify these cases and our ability to treat them,” he emphasized.
“Patients and [physicians] now have the necessary information on the long-lasting side effects of treatments to better understand the trade-offs between their benefits and harms. Survival no longer needs to be considered when deciding on treatment—as that’s the same for all three options. Now [patients] diagnosed with localized prostate cancer can use their own values and priorities when making the difficult decisions about which treatment to choose,” explained study coauthor Jenny Donovan, PhD, FMedSci, FFPH, NIHR, AcSS, OBE, Professor of Social Medicine at the University of Bristol Medical School.
The researchers also highlighted flaws in the current methods of predicting which patients with prostate cancer are likely to see their tumors grow quickly and metastasize. Initially, all of the patients participating in the trial were diagnosed with localized cancer and 77% of them were deemed low risk. A reassessment using more modern methods showed that a far greater number would now be considered intermediate risk—and in about 30% of the patients, the disease had already metastasized beyond the prostate.
Despite the finding that patients involved in the study had a higher grade and stage of the disease than initially thought, mortality rates were still low, even when patients with intermediate disease delayed or did not undergo radical treatment. However, some of the patients who subsequently died of their prostate cancer had been assessed as low risk at diagnosis—which the researchers marked as an issue of concern.
Conclusions
“The fact that the greater progression of disease seen under active monitoring didn’t translate into higher mortality will be both surprising and encouraging to urologists and patients. Active monitoring and biopsy protocols today are much more advanced than at the time this trial was conducted, so it’s possible we could improve on these outcomes still. It’s an important message for patients that delaying treatment is safe, especially [because] that means delaying side effects as well,” stated Peter Albers, MD, Professor and Chair of the Department of Urology at the Heinrich-Heine-University Düsseldorf and Chair of the Scientific Congress Office at the European Association of Urology.
“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,” he concluded.
Disclosure: The research in this study was funded by the National Institute for Health and Care Research. For full disclosures of the study authors, visit nejm.org.
