From 2004 to 2013, the incidence of new cases of metastatic prostate cancer increased by 72%, according to a study from researchers at Northwestern Medicine, Northwestern University, Chicago, IL, with the greatest increase seen in men aged 55 to 69 years old (92%)—precisely the population that is believed to derive the most benefit from screening and early treatment. Study results were published in the July 19 issue of the journal Prostate Cancer and Prostatic Diseases.
“One hypothesis is the disease has become more aggressive, regardless of the change in screening,” said senior author Edward M. Schaeffer, MD, PhD, chair of urology, Northwestern University Feinberg School of Medicine and Northwestern Medicine.
“The other idea is since screening guidelines have become more lax, when men do get diagnosed, it’s at a more advanced stage of disease. Probably both are true. We don’t know for sure but this is the focus of our current work,“ added Dr. Schaeffer, who is also a member of the Robert H. Lurie Comprehensive Cancer Center of Northwestern University.
Dr. Schaeffer and colleagues also found that in 2013, there was more advanced disease in men diagnosed, with an average prostate-specific antigen (PSA) of 49 ng/mL, and this was almost twice that of men diagnosed in 2004 (25 ng/mL).
“The fact that men in 2013 who presented with metastatic disease had much higher PSAs than similar men in 2004 hints that more aggressive disease is on the rise,” Dr. Schaeffer said. “If I were a patient, I would want to be vigilant. I firmly believe that PSA screening and rectal exams save lives.”
For this study, Dr. Schaeffer and colleagues included 767,550 men diagnosed with prostate cancer from 2004 through 2013 from 1,089 facilities throughout the United States. Rather than measuring the incidence, they measured the total number of cases of metastatic prostate cancer of cases per 100,000.
They found metastases in 3% of subjects. Furthermore, the number of new cases in 2013 was 2,890, compared with 1,685 in 2004, a 72% increase. Additionally, middle-aged men aged 55 to 69 years old had 702 new cases in 2004, compared with 1,345 in 2013, an increase of 92%.
In addition, Dr. Schaeffer and fellow researchers found that metastatic disease began rising in 2008, before the change in screening recommendations from the U.S. Preventive Services Task Force. Thus, investigators said, they can’t definitively link the increased cases to reduced screening alone, and called for refining screening guidelines as well as treatment based on individual patient risk factors and genetics.
“This will be particularly critical for population health economics in the U.S., considering the added cost of care for metastatic prostate cancer and an aging constituency whose population over the age of 65 will double to over a projected $80 million by the year 2050,” Dr. Schaeffer concluded.
This study was supported by National Institutes of Health grant 5U01CA196390 and the Prostate Cancer Foundation.