Higher-Risk Prostate Cancers in US May Have Increased

Nick Mulcahy

February 23, 2015

The rate of higher-risk prostate cancer as defined by PSA value at diagnosis appears to have risen slightly but significantly in the United States during 2011 and 2012, new research indicates.

The 3% increase in each of those two years coincides with changes that were made a few years earlier (In 2009 and 2011) to prostate cancer screening guidelines from the United States Preventive Services Task Force (USPSTF ), which discouraged screening, said study lead author Timothy E. Schultheiss, PhD, a radiation physicist at City of Hope in Duarte, California.

He spoke to reporters during a presscast today that precedes the 2015 Genitourinary Cancers Symposium, which starts later this week in Orlando, Florida.

However, a prominent urologist said that the two phenomena could not be definitively linked.

"It's far too early to say this is cause and effect," said Charles Ryan, MD, of the University of California, San Francisco, who moderated the presscast.

In other words, changes to the USPSTF screening guidelines may or may not have caused an uptick in prostate cancers with PSA values that are categorized as higher-risk disease.

Dr Schultheiss explained that higher-risk disease is defined as a prostate cancer with a blood PSA level > 10, which signifies either intermediate- or high-risk prostate cancer, irrespective of tumor stage and grade.

Increase in Only One Definer of High-Risk Disease

In the study, the investigators retrospectively reviewed information on 87,562 men treated for prostate cancer from January 2005 to June 2013 who are listed in the National Oncology Data Alliance, a proprietary database that captures cancer cases at more than 150 US hospitals.

They found that, from 2005 to 2011, the proportion of men with prostate cancer and PSA > 10 at diagnosis "decreased gradually."

However, for the years 2011 and 2012, the proportion of men diagnosed with intermediate- or high-risk cancer, based on blood PSA level, increased by 3% per year (P < .0004), for a total of 6%.

"Our study is the first to measure the changes in prostate cancer presentation in the period following the US Preventive Services Task Force's PSA screening recommendations," said Dr Schultheiss in a press statement.

Notably, Dr Schultheiss said that there was no increase in the rate of higher-risk prostate cancer as defined by either stage or tumor grade. "They did not change appreciably," he said.

In other words, higher-risk prostate cancer, which can be defined in any one of three ways (PSA, stage, or grade) was only seen as increasing via only one defining variable (PSA).

Dr Schultheiss and his colleagues described these findings in their abstract: "No significant trends in Gleason score were observed; the frequency of men with higher T stages generally decreased over the entire period without a notable change after 2011."

They also said that their PSA-related findings must be confirmed through further research.

Dr Ryan emphasized to reporters that the study was not a screening study and that it was uncertain as to why patients initially presented in the clinic. They might have been symptomatic or had a PSA screening test, he pointed out.

The investigators selected the National Oncology Data Alliance database because it included 2011 to 2013 data that were not available in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database at the time of this analysis.

Dr Schultheiss reminded the reporters that, in 2009, the USPSTF recommended that PSA not be used in prostate cancer screening in men aged 75 years or older.

In the new study, the fraction of men aged ≥75 years to present with PSA>10 increased by nearly double the rate (5.8% per year; P < .015) for men of all ages from 2011 to 2013.

In 2011, the USPSTF issued a draft recommendation that PSA not be used for prostate cancer screening, irrespective of age.

Dr Ryan reports financial ties to Astellas Pharma, Janssen Oncology, Bayer, Millennium, BIND, Karyopharm, and Novartis. The authors have disclosed no relevant financial relationships.

2015 Genitourinary Cancers Symposium: Abstract 143. To be Presented February 26, 2015.


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