Researchers believe prostate cancer has become more aggressive.
In the past decade, new cases of metastatic prostate cancer have rose 72%, with the highest increases found among men between the ages of 55- to 69-years-old.
For the study, researchers used the National Cancer Database, which included 767,550 men diagnosed with prostate cancer between 2004 and 2013 from 1089 facilities nationwide. The goal of the study was to measure the total number of metastatic prostate cancer cases rather than incidence. The findings were published in Prostate Cancer and Prostatic Diseases, a journal from Nature.
Of the patients involved in the study, 3% has metastases. The results showed that in 2013, the number of prostate cancer cases was 2890, compared with 1685 in 2004, a 72% increase. Furthermore, in men 55- to 69-years-old, the number rose 92% from 702 in 2004 to 1345 in 2013.
Authors noted that the rise of new prostate cancer cases in middle-aged men was a cause for concern, because men in that age group are believed to benefit the most from screenings and early treatment.
Researchers also found that in 2013 the average prostate-specific antigen (PSA) of men diagnosed with metastatic prostate cancer was 49, which was nearly double of those diagnosed in 2004 who had an average PSA of 25. This indicates a greater extent of disease at diagnosis.
“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,” said senior study author Edward Schaeffer. “If I were a patient, I would want to be vigilant. I firmly believe that PSA screening and rectal exams save lives.”
Over the course of the past decade, data has shown a substantial reduction in the amount of men screening for prostate cancer, and an associated decline in the overall number of new prostate cancer cases that are being reported.
“One hypothesis is the disease has become more aggressive, regardless of the change in screening,” Schaeffer said. “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.”
Although patients who are diagnosed with localized, aggressive prostate cancer are able to be cured through treatments, men who have metastatic prostate cancer are not, and instead only see a slowing of disease progression. Most who have metastatic prostate cancer will eventually succumb to the disease.
“There could be a significant increase in prostate cancer death rates if more people are diagnosed with metastatic disease, because treatments can only slow progression, it’s not curable,” Schaeffer said.
Authors noted that the rise of metastatic disease began in 2008, before screening recommendations from the US Preventive Services Task Force were changed. Furthermore, the study only measured the amount of metastatic prostate cancer cases and not the incidence.
Because of this, researchers stated that they were unable to definitively link the increase of prostate cancer cases to the reduction of screening alone.
“The results indicated that screening guidelines and treatment need to be refined based on individual patient risk factors and genetics,” said lead study author Adam Weiner. “This may help prevent the growing occurrence of metastatic prostate cancer and potential deaths associated with the disease. This also can help minimize over diagnosing and over treating men with low-risk prostate cancer who do not need treatment. This will be particularly critical for population health economics in the US, 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.”