According to a recent study, cases of metastatic prostate cancer have increased considerably in the last decade, potentially due to a recent decrease in the number of men being screened for disease. Researchers at Northwestern University reported more men with metastatic prostate cancer are being diagnosed with worse and more aggressive tumors, raising concerns about surveillance and diagnosis for an incurable form of the disease. The study, which was published in Prostate Cancer and Prostatic Diseases, analyzed the medical data of 767,550 men who had been diagnosed with prostate cancer between the years 2004 and 2013, and found that the number of new cases rose to 72% within the last decade.
During the same time period, researchers also found the number of metastatic prostate cancer patients between the ages of 55 and 69 increased by 92%. Men with metastatic prostate cancer had higher PSA levels than similar men in 2004, which suggests the more aggressive disease is becoming more common, but researchers say the large increase in older patients with a worse form of the disease may be catchable with changes in screening. The study also cited a substantial decline in the number of men being screened for prostate cancer, as well as an associated decrease in the overall number of new cases of prostate cancer reported.
“The results indicate that screening guidelines and treatment need to be refined based on individual patient risk factors and genetics. This may help prevent the growing occurrence of metastatic prostate cancer and potential deaths associated with the disease. This also can help minimize overdiagnosing and overtreating men with low-risk prostate cancer who do not need treatment.”
Dr. Adam Weiner, a Feinberg urology resident at Northwestern’s School of Medicine
The controversial study however wasn’t without its detractors and several experts questioned the validity of their research. For example, The American Cancer Society questioned the study’s methodology and findings, posting this statement on its website from Chief Medical Officer Dr. Otis W. Brawley:
“This study makes a dramatic claim about an issue all of us have been watching eagerly: namely, whether less PSA screening might lead to more advanced cancers. But the current analysis is far from adequate to answer that question sufficiently.
The way epidemiologists measure things like incidence and mortality is to study rates, the number of cases per a number of people (usually per 100,000) to look for trends. But this study, done by a group of urologists, didn’t do that. Rather than measure rates of metastatic disease, they looked at the number of cases. That is far from the same thing.
Epidemiologists learned long ago that you can’t simply look at raw numbers. A rising number of cases can be due simply to a growing and aging population among other factors. In addition, in this study, the rise they detected began before USPSTF guidelines for screening changed. There may or may not be a rise in the rates of metastatic disease; but because of a flawed analysis, this study does not answer that important question.
So why was this unusual study leading to calls? It’s a safe guess that a press release sent to reporters nationwide with a somewhat alarming headline was the reason.”
Many of the initial news articles that were released regarding the study reported the supposed increase without caveats, and even fewer quoted the cancer society or outside experts on the matter. Screening for prostate cancer has long been a subject of debate among experts but The American Cancer Society recommends that men “make an informed decision with their healthcare provider about whether to be screened for prostate cancer. A decision should only be made after a patient has gotten all the information in relation to the uncertainties, risks, and potential benefits of prostate cancer screening.