Early Prostate Cancer: Treat or Monitor?
A new study published online in September 2016 in the New England Journal of Medicine may help reassure men diagnosed with early prostate cancer.
Whether they choose surgery, radiation therapy, or no treatment whatsoever, their risk of dying from prostate cancer over the next 10 years is minuscule—less than 1 percent, say researchers at the Universities of Oxford and Bristol in England. And the treatment they eventually choose makes no significant difference.
Cancer of the prostate is the most commonly diagnosed life-threatening cancer in men, and after lung cancer, it holds the second highest mortality rate, accounting for 9 percent of all male cancer deaths. This year, the American Cancer Society estimates that there will be 181,000 new cases of prostate cancer diagnosed in the United States and that 26,000 will die from their disease.
While prostate cancer can be lethal, it’s an exception in the world of cancer because it’s often slow growing, and for many men it poses little risk. Typically, men with this diagnosis often die from other causes than prostate cancer.
When those low-risk cancers are treated, either with surgery or radiation therapy, the cure rate is extremely high, but men are often left with bothersome side effects such as erectile dysfunction and urination issues that affect the quality of life. Understanding this has led to heated debate, conflicting opinions, and just plain confusion about what treatment, if any, is needed for men diagnosed with early prostate cancer.
To treat or not?
The Prostate Testing for Cancer and Treatment trial was launched in 1999 with 1,643 men ages 50 to 69 diagnosed with localized prostate cancer, which means that the low-risk cancer was confined to the prostate and had not metastasized, or spread, to nearby bones or organs.
The men had prostate-specific antigen (PSA) scores of 3 or higher, with approximately three-quarters of the men with Gleason scores of 6, while others had higher scores, which put them more at risk of cancer progression. Gleason scores are numerical values given to prostate cancers by pathologists to describe tumor aggressiveness, and they range from 6 to 10, with scores of 8 through 10 being worse.
The men were then randomly assigned to either undergo surgery to remove the prostate or external beam radiation therapy. The third group, which was comprised of men with low and intermediate risk, was offered active surveillance, with treatment offered only if the cancer progressed. The goal of this study was to determine the relative effectiveness and safety of the three different cancer options after an average of a decade of follow-up.
At six months, almost 90 percent of men who had surgery and almost 80 percent of men who had radiation therapy reported erection difficulties. While death rates from the cancer did not differ, 33 men who were being monitored had their disease metastasize, compared with 16 who had radiation therapy, and 13 who underwent radical prostatectomy surgery.
"This study tells us for the first time something that we urologists have believed but did not know for sure," says Patrick Walsh, M.D., a prostate cancer surgery pioneer and the University Distinguished Service Professor of Urology at Johns Hopkins University School of Medicine in Baltimore. "For those patients with low-risk cancer, surgery and radiation have equivalent results. It also reaffirms something we have said forever: If your lifespan is less than 10 years, one does not need to seek out aggressive treatment."
He noted, however, that the average age of the men in the study was 62. "Thus, those men who developed metastases are likely to die from prostate cancer. This observation should temper the enthusiasm of young men to assume that prostate cancer does not need to be treated,” he added.
When to consider active surveillance
Jacek Mostwin, M.D., professor of urology at Johns Hopkins, and medical director of the Scientific American Prostate Disorders Bulletin points out that active monitoring, as was offered to the relatively healthy young men in the study, did nothing more than follow a patient’s PSA level every three months in the first year and twice yearly thereafter. Men were offered a reassessment—and possible treatment—if PSA had risen by 50 percent during the previous year.
“Minimal monitoring may explain the higher rates of metastatic disease and death in the active monitoring group,” Mostwin says. “But we now know that men need to be monitored much more carefully for the rest of their lives, or disease progression will be missed, and men will be put at risk.”
Active surveillance offers men who have prostate cancer that is unlikely to cause harm the option of careful monitoring with the intention to treat should the disease change over time.
This management approach is most often recommended for men with very low- to low-risk prostate cancers. Active surveillance appears to be most appropriate for men age 65 years and older with an expected lifespan of 15 to 20 years.
Younger men with underlying medical ailments that will limit their life expectancy or whose priority is to avoid treatment side effects are also reasonable candidates for active surveillance.
Why biopsies are important
Experts at Hopkins emphasize the importance of having adequate biopsy sampling before choosing active surveillance. In addition, patients will undergo a prostate MRI and targeted biopsies of any lesions that are suspicious. This is especially important for men who do not meet the strict criteria of very-low-risk prostate cancer.
At Hopkins, men who choose active surveillance must see their doctor regularly and undergo testing to determine whether the cancer has progressed. A typical follow-up plan requires a digital rectal exam at least annually, a PSA test every three to six months, as well as a prostate biopsy every one to four years.
“The triggers for intervention that most commonly prompt treatment are the presence of a higher grade cancer on surveillance biopsy, or the finding of more extensive low-grade cancer,” Mostwin says. “A rising PSA should provoke further evaluation to exclude the presence of a high-grade cancer, but not initiation of treatment in most cases.”
Current guidelines from the American Society of Clinical Oncology and the National Comprehensive Cancer Network indicate active surveillance as the recommend option for most patients with low-risk cancer. “When it comes to decision making about their cancer,” Mostwin says, “men have to put the time into understanding the facts about their prostate cancer, decide if they really need to be treated, or if they can safely adopt the recommended active surveillance protocol.”