Analysis Shows Increase in Higher-Risk Prostate Cancers

The proportion of men diagnosed with intermediate- or high-risk cancer, based on blood prostate-specific antigen (PSA) level, increased by nearly 6% from 2011 to 2013, according to an analysis of men treated for the disease since 2005.

Although the United States Preventive Services Task Force (USPSTF) issued a draft recommendation in 2011 that PSA not be used for prostate cancer screening regardless of age, a study presented in advance of the 2015 Genitourinary Cancers Symposium measured the potential consequences of that decision. The USPSTF had also drafted a similar recommendation in 2009, recommending that PSA not be used for prostate cancer screening in patients over the age of 74.

The study found a notable increase in higher-risk cases of the disease between 2011 and 2013. It is estimated that this trend could produce an additional 1400 prostate cancer deaths annually.

“The purpose of our study was to assess over time the PSA values at the time of prostate cancer diagnosis and the NCCN (National Comprehensive Cancer Network) risk categories at the time of cancer diagnosis,” said lead study author Timothy E. Schultheiss, PhD, during a pre-Symposium press-cast. Schultheiss is professor and director of radiation physics at City of Hope in Duarte, California.

Data were analyzed on 87,562 patients diagnosed with prostate cancer between January 2005 and June 2013 and collected from the National Oncology Data Alliance (Elekta/IMPAC Medical Systems, Inc, Sunnyvale, CA).

Frequencies were examined by date of diagnosis, grouped in 6-month intervals, and trends were assessed using linear regression.

A blood PSA level greater than 10 signifies intermediate-or high-risk prostate cancer, irrespective of tumor stage and grade.

The proportion of patients with prostate cancer and PSA greater than 10 decreased gradually from 2005 to 2011. However, the proportion of patients diagnosed with intermediate- or high-risk prostate cancer, based on blood PSA level, increased by 3% each year between 2011 and 2013 (P <.0004).

The fraction of men older than 75 years with a PSA >10 increased by nearly double the rate of men in all age groups from 2011 to 2013.

Rates of intermediate- or higher-risk prostate cancer were stable at 70% to 73% prior to 2011; however, that rate rose by 2.9% annually after 2011 (P <.003) without evidence of a plateau.

The authors estimated that with 233,000 new prostate cancer cases predicted in the United States in 2014, there will be 14,000 additional higher-risk prostate cancer diagnoses nationwide in 2014 compared with 2011, which may ultimately lead to 1400 deaths from prostate cancer each year. These predictions are based on the 2014 estimated number of new prostate cancer cases and the relative survival of patients with low- versus high-risk cancer.

“Whether this effect can be attributed to the 2009 or 2011 recommendation by USPSTF is speculative,” Schultheiss said during the presscast. “However, the USPSTF did acknowledge the existence of this effect but regarded it as insignificant. We believe that our data indicate that the USPSTF might reconsider their recommendation.”

Currently, the 10-year prostate cancer survival rates are approximately 95% for low-risk, 75% to 90% for intermediate risk, and 60% to 80% percent for high-risk disease.

Researchers plan to update the analysis as new registry data become available.

“This is a study that really does add some new insight to the ongoing debate on the risks and benefits of prostate cancer screening, and I think underscores the importance of continuing to study the issue of changing guidelines,” said Charles Ryan, MD, ASCO Expert and GU News Planning Team Member during the presscast.

Hall MD, Schultheiss TE, Farino G, and Wong JYC. Increase in higher risk prostate cancer cases following new screening recommendation by the US Preventive Services Task Force (USPSTF). Presented in press cast of the 2015 Genitourinary Cancers Symposium; February 23, 2015, Orlando, FL. Abstract 143.

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