Most men get aggressive prostate cancer treatment even for low-risk disease
July 27, 2010
by Brendon Nafziger, DOTmed News Associate Editor
Most men get aggressive prostate cancer treatment even if they have low-risk disease, according to a new study.
A paper published Monday in Archives of Internal Medicine found most men diagnosed with cancer with low prostate-specific antigen levels still had their prostates removed or their tumors blasted with radiation, even though they were unlikely to have aggressive, high-risk cancers.
"There might be some degree of discrepancy between risk and the way that cancer's treated," Dr. Mark N. Stein told DOTmed News.
Dr. Stein is a co-author of the study, a medical oncologist with the Cancer Institute of New Jersey and an assistant professor of medicine with UMDNJ-Robert Wood Johnson Medical School.
The authors caution that lowering the PSA cutoff levels used to determine whether to do a prostate biopsy could result in even larger numbers of men undergoing potentially unnecessary treatment.
While there's no strict cutoff for cancer risk, as deadly cancers can occur with nearly any PSA level, having PSA levels of 4 nanograms per milliliter is the typical trigger for getting a needle biopsy.
"Although abandoning an upper limit of normal for PSA level would allow physicians to detect more cancer, the benefits of diagnosing prostate cancer would likely be offset by treatment complications related to cancers that might never have caused harm," write the authors, led by Yu-Hsuan Shao, also with the New Brunswick, N.J.-based Cancer Institute of New Jersey.
In what the researchers call one of the largest studies of its kind, they examined results of 123,934 men diagnosed with prostate cancer between 2004 and 2006, using data drawn from the Surveillance, Epidemiology and End Results system. Of these men diagnosed with prostate cancer, about 14 percent had PSA levels of 4 nanograms per milliliter or lower.
In this lower-PSA group, around 54 percent were classified as having a low-risk cancer, yet almost 75 percent underwent a radical prostatectomy, the total removal of the organ, or had radiation therapy, the report said.
"Despite their lower risk of having clinically significant disease, treatment rates for men with PSA values of 4.0 nanograms per milliliter or lower were comparable to those of men presenting with PSA values between 4 and 20 nanograms per milliliter," the authors wrote.
For those diagnosed with cancer, complete prostate removal was done on 44 percent of men with PSA levels of less than 4 nanograms per milliliter, while 38 percent of men with PSA values between 4.1 and 10 also had the surgery. Radiation therapy was performed on 33 percent of men with PSA values 4 or lower, and 40 percent between 4.1 and 10.
Of note, around 66 percent of men between the ages of 65 and 74 with low-risk disease and a low PSA value received aggressive treatment, even though ongoing research suggests men older than 65 with low-risk disease treated with prostate removal don't do better than those undergoing conservative management, the authors said.
"These findings suggest that many contemporary men receiving treatment for localized prostate cancer are unlikely to benefit from the intervention," the authors wrote.
Another curious finding, which the researchers say they don't have enough information to explain, is that men whose prostate cancer was detected after a routine screening and who had low PSA values were almost one and a half times more likely to receive aggressive treatment than those whose cancer was diagnosed after reports of symptoms or for other causes.
The reason? "[It's] hard to know," Stein said.
The authors said if the threshold for biopsy dropped from 4 to 2.5 nanograms per milliliter, the number of men getting biopsies could double to 6 million. Of these men, about 32 percent would be diagnosed with prostate cancer after needle biopsy.
"Based on the results in the present study, 82.5 percent of these 1.9 million men would receive attempted curative treatments, while only 2.4 percent would have high-grade cancer," the researchers wrote. "However, no evidence suggests that delaying biopsy until the PSA level reaches 4.0 nanograms per milliliter would result in an excessive number of potentially non-curable disease cases."
Nonetheless, Stein warns that researchers haven't figured out whether the risks of over-treating low-risk prostate cancer actually outweigh the risks of missing early cancers. In the study, the authors note that the relative five-year survival rate for all stages of prostate cancer climbed from 69 percent to almost 99 percent in the last three decades, and this could partly be due to finding cancers earlier through screening programs.
"We really need to understand who truly is at low risk," Stein said.
To that end, Stein said a massive joint Canada-United States study currently underway is investigating health outcomes for men with favorable cancer diagnoses treated with active surveillance.
A paper published Monday in Archives of Internal Medicine found most men diagnosed with cancer with low prostate-specific antigen levels still had their prostates removed or their tumors blasted with radiation, even though they were unlikely to have aggressive, high-risk cancers.
"There might be some degree of discrepancy between risk and the way that cancer's treated," Dr. Mark N. Stein told DOTmed News.
Dr. Stein is a co-author of the study, a medical oncologist with the Cancer Institute of New Jersey and an assistant professor of medicine with UMDNJ-Robert Wood Johnson Medical School.
The authors caution that lowering the PSA cutoff levels used to determine whether to do a prostate biopsy could result in even larger numbers of men undergoing potentially unnecessary treatment.
While there's no strict cutoff for cancer risk, as deadly cancers can occur with nearly any PSA level, having PSA levels of 4 nanograms per milliliter is the typical trigger for getting a needle biopsy.
"Although abandoning an upper limit of normal for PSA level would allow physicians to detect more cancer, the benefits of diagnosing prostate cancer would likely be offset by treatment complications related to cancers that might never have caused harm," write the authors, led by Yu-Hsuan Shao, also with the New Brunswick, N.J.-based Cancer Institute of New Jersey.
In what the researchers call one of the largest studies of its kind, they examined results of 123,934 men diagnosed with prostate cancer between 2004 and 2006, using data drawn from the Surveillance, Epidemiology and End Results system. Of these men diagnosed with prostate cancer, about 14 percent had PSA levels of 4 nanograms per milliliter or lower.
In this lower-PSA group, around 54 percent were classified as having a low-risk cancer, yet almost 75 percent underwent a radical prostatectomy, the total removal of the organ, or had radiation therapy, the report said.
"Despite their lower risk of having clinically significant disease, treatment rates for men with PSA values of 4.0 nanograms per milliliter or lower were comparable to those of men presenting with PSA values between 4 and 20 nanograms per milliliter," the authors wrote.
For those diagnosed with cancer, complete prostate removal was done on 44 percent of men with PSA levels of less than 4 nanograms per milliliter, while 38 percent of men with PSA values between 4.1 and 10 also had the surgery. Radiation therapy was performed on 33 percent of men with PSA values 4 or lower, and 40 percent between 4.1 and 10.
Of note, around 66 percent of men between the ages of 65 and 74 with low-risk disease and a low PSA value received aggressive treatment, even though ongoing research suggests men older than 65 with low-risk disease treated with prostate removal don't do better than those undergoing conservative management, the authors said.
"These findings suggest that many contemporary men receiving treatment for localized prostate cancer are unlikely to benefit from the intervention," the authors wrote.
Another curious finding, which the researchers say they don't have enough information to explain, is that men whose prostate cancer was detected after a routine screening and who had low PSA values were almost one and a half times more likely to receive aggressive treatment than those whose cancer was diagnosed after reports of symptoms or for other causes.
The reason? "[It's] hard to know," Stein said.
The authors said if the threshold for biopsy dropped from 4 to 2.5 nanograms per milliliter, the number of men getting biopsies could double to 6 million. Of these men, about 32 percent would be diagnosed with prostate cancer after needle biopsy.
"Based on the results in the present study, 82.5 percent of these 1.9 million men would receive attempted curative treatments, while only 2.4 percent would have high-grade cancer," the researchers wrote. "However, no evidence suggests that delaying biopsy until the PSA level reaches 4.0 nanograms per milliliter would result in an excessive number of potentially non-curable disease cases."
Nonetheless, Stein warns that researchers haven't figured out whether the risks of over-treating low-risk prostate cancer actually outweigh the risks of missing early cancers. In the study, the authors note that the relative five-year survival rate for all stages of prostate cancer climbed from 69 percent to almost 99 percent in the last three decades, and this could partly be due to finding cancers earlier through screening programs.
"We really need to understand who truly is at low risk," Stein said.
To that end, Stein said a massive joint Canada-United States study currently underway is investigating health outcomes for men with favorable cancer diagnoses treated with active surveillance.