At the time of diagnosis, 77 percent of prostate cancer cases are localized; 13% have progressed to regional lymph nodes, and 6% have distant metastases. Localized and regional prostate cancer had a 100% 5-year relative survival rate, compared to 30.5 percent for metastatic patients.
According to a new study from USC’s Keck Medicine, the incidence rate of metastatic prostate cancer has considerably increased among men 45 and older, which aligns with recommendations against frequent prostate cancer screenings.
“This study is the first to document a continued rise in metastatic prostate cancer using the most up-to-date population dataset,” said Mihir M. Desai, MD, MPH, a urologist with Keck Medicine and co-lead author of the study. “The discovery has important ramifications for men because prostate cancer, when caught early, typically through a screening, is very treatable and often curable.”
Desai is also a clinical urology professor at USC’s Keck School of Medicine and an associate member of the USC Norris Comprehensive Cancer Center, which is part of Keck Medicine. Routine prostate-specific antigen (PSA) screening for prostate cancer began about three decades ago in the United States. PSA checks determine the amount of PSA in the blood, and high levels can suggest malignancy.
This study is the first to document a continued rise in metastatic prostate cancer using the most up-to-date population dataset. The discovery has important ramifications for men because prostate cancer, when caught early, typically through a screening, is very treatable and often curable.
Mihir M. Desai
Screenings resulted in a decrease in both metastatic prostate cancer and prostate cancer fatalities. The benefit of frequent screenings, however, was offset by the dangers of overdiagnosis and overtreatment of low-risk prostate cancer.
The US Preventive Services Task Force (USPSTF), a leading national organization in disease prevention and evidence-based medicine, recommended against routine PSA screening for men over the age of 75 in 2008. In 2012, a recommendation against all men being screened was issued.
According to research, prostate cancer screenings for men fell across all age groups and racial groups after the recommendations changed. Keck Medicine researchers wanted to assess metastatic prostate cancer trends before and after the USPSTF recommendations against screenings.
They identified men 45 and older with a diagnosis of invasive prostate cancer from 2004-2018 through the Surveillance, Epidemiology and End Results (SEER) Program cancer incidence database.
More than 836,000 prostate cancer patients 45 and older were documented in the SEER database between 2004 and 2018, the most recent year for which data was available. There were 26,642 cases of metastatic prostate cancer recorded in men aged 45 to 74, and 20,507 cases in men aged 75 and up.
In the 45-74 age range, the incidence rate of metastatic prostate cancer stayed steady from 2004 to 2010, then grew by 41% from 2010 to 2018. In men 75 and older, the incidence rate fell from 2004 to 2011, but surged by 43% from 2011 to 2018. The increases were seen across all races in both age groups.
The researchers point out that these increases contrast with the declining trends in metastatic prostate cancer incidence between 2004 and 2009, before the USPSTF began advocating routine PSA tests for males.
The authors also discuss the possibility that factors other than the change in screening recommendations in 2008 and 2012, such as the use of new, cutting-edge diagnostic and staging tools that are better able to detect low-volume (less invasive) metastatic prostate cancer, may have played a role in the increase in cancer cases.
However, they conclude that such techniques are not widespread, and typically not used for first-time cancer detection, so are unlikely to be of significance in the findings.
“This data is really important because it shows the importance of constantly reassessing the impact of policy decisions,” said Giovanni Cacciamani, MD, MSc, co-lead author of the study, assistant professor of research urology and radiology at the Keck School, and associate member of USC Norris. “Otherwise, we may continue to observe an increase in metastatic prostate cancer.”
The authors believe that the initial reasons for discontinuing screenings, that they lead to overdiagnosis and overtreatment of low-risk prostate cancer, are likewise out of date.
“Urologic centers of excellence, such as USC Urology, are constantly researching ways to leverage technologies to improve patient outcomes and reduce treatment side effects,” said Inderbir Gill, MD, chairman of the Catherine and Joseph Aresty Department of Urology, distinguished professor of urology at the Keck School, executive director of the USC Institute of Urology, and a member of USC Norris. “More improved techniques, such as biomarkers and magnetic resonance imaging, have already enhanced detection of clinically important malignancies, while active surveillance is increasingly being employed for low-risk and favorable intermediate-risk disease, reducing the hazards of overtreatment.”
