Cases of prostate cancer are on the rise in California, according to new research.

A study by UC San Francisco (UCSF) included nearly 388,000 men who had prostate cancer between 2004 and 2021.

The incidence rate of cases increased 6.7% per year on average between 2011 and 2021, the JAMA-published research revealed.

Although cases rose, prostate cancer mortality rates declined 2.6% per year from 2004 to 2012, and plateaued from 2012 to 2021.

These trends were similar across age, race, ethnicity and region, the researchers found.

The increase in prostate cancer cases is linked to a shift in PSA (prostate-specific antigen) testing recommendations. In 2012, the US Preventative Services Task Force (USPSTF) altered their guidelines and no longer advised for these screenings, as stated in a UCSF press release.

This change was implemented to decrease the number of prostate cancer patients receiving unnecessary treatments for less serious forms of the disease that could potentially be harmful.

According to UCSF, prostate cancer is the most common cancer among men and the second-leading cause of cancer deaths.

It is important to note that the majority of prostate cancer tumors are low-grade and generally do not spread. The PSA test is unable to distinguish between aggressive and non-aggressive tumors, resulting in the diagnosis of cancers that may not pose a significant threat to the individual’s health in the long term, according to the press release.

“On the other hand, if screening isn’t done, timely diagnosis of more advanced cancers can be missed – those cancers might have been successfully treated if found early,” UCSF noted.

The freeze in screenings “unfortunately may have led to one of the largest subsequent rises in incidence of distant stage disease,” according to the researchers.

UCSF wrote that these findings “reinforce the need for screening that can identify potentially fatal tumors without raising false alarms about ones that pose no threat to the patient.”

“Figuring out the best way to screen for prostate cancer continues to be a challenge for researchers and doctors,” lead study author Dr. Erin L. Van Blarigan, UCSF associate professor of epidemiology, biostatistics and urology, said in a statement.

“Without screening, the number of men diagnosed with advanced prostate cancer – when treatments are less effective – increases fast.”

Fox News senior medical analyst Dr. Marc Siegel, who was not involved in the study, also called out the need for regular screenings.

“[Screenings] decreased in many areas, including California, as the US Preventive Services Task Force recommended against PSA as a regular screening tool, which I always disagreed with,” he told Fox News Digital. “Especially as MRI advanced, so not all elevated PSA automatically meant a biopsy.”

Based on the increase in prostate cancer cases across all ages, Siegel emphasized the need to “diagnose it early for better outcomes.”

Siegel suggested that the increase in cases could also be due to a variety of factors, including the obesity epidemic, ultraprocessed foods and an increase in alcohol consumption and fatty foods.

David R. Wise, MD, PhD, urologic oncologist and the service chief of the Genitourinary Medical Oncology Program at NYU Langone Perlmutter Cancer Center, also reacted to this rise in cases.

“The increasing incidence of metastatic prostate cancer in California in the 2010s is consistent with reports by others, including the American Cancer Society,” Wise, who was not involved in the research, told Fox News Digital.

“It likely reflects the aftermath of diminished prostate cancer screening. A return to prostate cancer screening will likely reverse this effect.”

“Optimized screening, enhanced by MRI and novel blood-based biomarkers, is now available and is poised to spare men with low risk disease from unnecessary treatment while ensuring early detection for men with aggressive cancer,” he added.

Fox News Digital’s Khloe Quill contributed reporting.