The NCDB Forgot about DRE?
Esther L. Finney, MD1, Harras B. Zaid, MD1, David Canes, MD1, Alireza Moinzadeh, MD, MBA1, Kristian B. Stensland, MD, MPH2.
1Lahey Hospital and Medical Center, Burlington, MA, USA, 2University of Michigan, Ann Arbor, MI, USA.
BACKGROUND: The digital rectal exam (DRE) is currently included in the AUA/NCCN risk strata for prostate cancer. Specifically, a patient cannot be “low risk” if they have palpable disease in more than half of one side of the prostate (cT2b or higher), which may render them ineligible for surveillance or other lower intensity treatments. However, it is unclear how frequently DRE findings are reported, particularly with respect to substaging (i.e., cT2a, cT2b, cT2c). We hypothesized that there is no documentation of tumor substage for a large number of patients, and that the rate of reporting has decreased over the last decade. METHODS: We queried the National Cancer Database for nonmetastatic prostate cancer cases from 2004-2016. We evaluated the number of cases missing clinical T2 substaging for each year (cTx). To estimate the potential change in risk grouping if DRE were missing, we also calculated the number of patients whose risk stratification would change based on clinical exam alone (i.e., PSA and Gleason score) for patients whose Gleason Grade Group, PSA, and clinical T2 substage were available.
RESULTS: A total of 335,852 cases were included, of which 65,376 (20%) were missing a substage. The rate of missing substage documentation increased from 15% of cT2 cases in 2004 to 25% in 2015, then dropped to 10% in 2016. Of the patients with available cT2 substage (cT2a-c), 2,591 (11%) of 23,706 otherwise low risk patients were upstaged to unfavorable intermediate risk based on DRE alone. Similarly, of 30,385 otherwise favorable intermediate risk patients, 8,479 (28%) were upstaged to unfavorable intermediate risk based on DRE alone.
CONCLUSIONS: One in five prostate cancer cases is missing clinical T substaging, knowledge of which changes risk stratification in 20% of patients with otherwise low or favorable intermediate risk. This disconnect may reflect poor recording or reporting of DRE for palpable disease, or suggests that this level of accuracy in the DRE for risk stratification purposes may need to be reevaluated. Even if this finding only applies to the NCDB, given one in five localized prostate cancer cases is missing key staging information, use of the AUA/NCCN risk stratification with the NCDB should be done with caution.
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