Published online Mar 24, 2014. doi: 10.5410/wjcu.v3.i1.47
Revised: November 22, 2013
Accepted: December 13, 2013
Published online: March 24, 2014
Processing time: 178 Days and 19.8 Hours
AIM: To find risk factors of cancer in patients who had a repeat biopsy and to develop the nomogram using our cohort.
METHODS: Among 3500 patients who had a prostate biopsy over 11 years between 2000 and 2010 at our hospital, we studied a total of 807 repeat biopsy sessions in 459 patients who had at least 1 initial negative biopsy. At each biopsy session, we recorded patient age, number of previous biopsy sessions, number of biopsy cores, number of previously negative biopsy cores, months from the initial biopsy, months from the previous biopsy, serum PSA, PSA slope, digital rectal examination findings, hypoechoic lesions suspicious for a cancer on transrectal ultrasonography, total prostate volume, transitional zone (TZ) volume, PSA density, PSA TZ density and history of high grade prostatic intraepithelial neoplasia (HGPIN) or atypical small acinar proliferation (ASAP). Clinical and pathological variables were correlated with the outcome of repeat biopsies. A nomogram was developed based on logistic regression analyses and calibration was performed.
RESULTS: Overall, 17% of repeat biopsies had a cancer. With receiver operating characteristics analyses, the highest area under the curve (AUC) was obtained based on all available 13 variables, which were age, PSA, digital rectal examination, PSA density, prostate volume, TZ volume, PSA TZ density, cumulative number of biopsy cores, HGPIN, ASAP, months from previous negative biopsy, initial negative biopsy and number of biopsy cores. Based on multivariable logistic regression analysis, a nomogram was constructed with an AUC of 0.74, which was greater than that of any single risk factor. The calibration plot seemed to be good.
CONCLUSION: Our nomogram for predicting a positive repeat biopsy can provide probabilities for cancer and may help clinical judgment on whether to do a repeat prostate biopsy.
Core tip: Although prostate cancer is found in about 30% of patients at the initial biopsy session, there is a need to identify those with a negative result but who are at high risk. Although individual risk factors have been found to be associated with cancer, patient counseling requires the integration of multiple risk factors to obtain a prediction for the individual. We developed a nomogram that predicts a positive biopsy after a previous negative biopsy session. It provides a wide range of probabilities for cancer and may help clinical judgment of whether to do a repeat prostate biopsy.