Detection rate of clinically insignificant prostate cancer increases with repeat prostate biopsies

Clinicopathologic differences between prostate cancers detected during initial and repeat transrectal ultrasound-guided biopsy in Korea

Purpose

The aim of this study was to investigate clinicopathologic differences between prostate cancer (PCa) detected at initial and repeat transrectal ultrasound-guided prostate biopsy in a large Korean cohort.

Materials and Methods

From 2000 through 2012, a total of 7,001 patients underwent transrectal ultrasound-guided prostate biopsy at 6 centers in Daegu and Gyeongbuk provinces. Of these 7,001 patients, the initial biopsy was positive for PCa in 2,118 patients. Repeat biopsy was performed in 374 of the 4,883 patients with an initial negative finding and a persistently elevated prostate-specific antigen (PSA) level, nodules or asymmetry by digital rectal examination (DRE), high-grade prostatic intraepithelial neoplasia, or atypical small acinar proliferation. Numbers of biopsy cores varied from 6 to 12 according to center and biopsy date.

Results

Cancer was diagnosed in 2,118 of the 7,001 patients (30.3%) at initial biopsy and in 86 of the 374 patients (23.0%) at repeat biopsy. The repeat biopsy rate was 5.3%. Mean PSA values were 68.7±289.5 ng/mL at initial biopsy and 18.0±55.4 ng/mL at repeat biopsy (p<0.001). The mean number of cancer-positive cores per biopsy was 5.5±3.5 for initial biopsy and 3.0±2.9 for repeat biopsy (p<0.001). Mean Gleason score was 7.5±1.4 at initial biopsy and 6.6±1.3 at repeat biopsy (p<0.001). For detected cancers, the low-stage rate was higher for repeat biopsy than for initial biopsy (p=0.001).

Conclusions

Cancers detected at repeat biopsy tend to have lower Gleason scores and stages than cancers detected at initial biopsy. The present study shows that repeat biopsy is needed in patients with a persistently high PSA or abnormal DRE findings.

Overdiagnosis and overtreatment of prostate cancer

CONTEXT

Although prostate cancer (PCa) screening reduces the incidence of advanced disease and mortality, trade-offs include overdiagnosis and resultant overtreatment.

OBJECTIVE

To review primary data on PCa overdiagnosis and overtreatment.

EVIDENCE ACQUISITION

Electronic searches were conducted in Cochrane Central Register of Controlled Trials, PubMed, and Embase from inception to July 2013 for original articles on PCa overdiagnosis and overtreatment. Supplemental articles were identified through hand searches.

EVIDENCE SYNTHESIS

The lead-time and excess-incidence approaches are the main ways used to estimate overdiagnosis in epidemiological studies, with estimates varying widely. The estimated number of PCa cases needed to be diagnosed to save a life has ranged from 48 down to 5 with increasing follow-up. In clinical studies, generally lower rates of overdiagnosis have been reported based on the frequency of low-grade minimal tumors at radical prostatectomy (1.7-46.8%). Autopsy studies have reported PCa in 18.5-38.5%, although not all are low grade or low volume. Factors influencing overdiagnosis include the study population, screening protocol, and background incidence, limiting generalizability between settings. Reported rates of overtreatment vary widely in the literature, although contemporary international studies suggest increasing use of conservative management.

CONCLUSIONS

Epidemiological, clinical, and autopsy studies have been used to examine PCa overdiagnosis, with estimates ranging widely from 1.7% to 67%. Correspondingly, estimates of overtreatment vary widely based on patient features and may be declining internationally. Careful patient selection for screening and reducing overtreatment are important to preserve the benefits and reduce the downstream harms of prostate-specific antigen testing. Because all of these estimates are extremely population and context specific, this must be considered when using these data to inform policy.

PATIENT SUMMARY

Screening reduces spread and death from prostate cancer (PCa) but overdiagnoses some low-risk tumors that may not have caused harm. Because treatment has potential side effects, it is critical that not all patients with PCa receive aggressive treatment.