[Study on the length and quality of prostate biopsy tissue strips]

To improve the diagnostic yield of prostate biopsy, which we can achieve by puncture more sites and number of cores, another way to obtain more tissue is to take longer tissue strips. In this study, we evaluated the effect of strip length on cancer diagnosis by needle biopsy and derived a cutoff value of strip length to improve cancer detection.

The pathological reports of 754 patients with suspected prostate cancer who underwent transperineal prostate biopsy were retrospectively analyzed. The age, serum prostate specific antigen (PSA), prostate volume, Gleason score and tissue strip length were analyzed. The length of the tissue strip was compared between the biopsy positive patients and the biopsy negative patients, and the patients were divided into group A（biopsy positive group）and group B（biopsy negative group）, respectively. Statistical analysis of tissue strip lengths was performed to determine cutoff values for biopsy length quality.

A total of 10 556 tissue strips were obtained from 754 patients, and 45.1 % of the patients were pathologically diagnosed as prostate cancer. The median length of the tissue strip was 10.5 (9.5, 12.5) mm, the median age was 69 (64,75) years, the median PSA was 12.4 (8.6, 20.8) μg/L, and the median prostate volume was 44.8 (30.5, 64.4) ml. The median length of tissue strips in group A and group B was 11 (10,13) mm and 10 (9,12) mm, respectively. Receiver operating characteristic (ROC) curve analysis was performed on the length of tissue strips in all cases, and the cutoff value of quality assurance was 11.8mm, the area under curve (AUC) was 0.82, and the cut-off value of quality assurance was 11.8mm. Sensitivity 71.4%, specificity 73.8%(P<0.001).

In transperineal prostate biopsy, the cancer detection rate of tissue strips may increase with length. The results of ROC analysis showed that 11.8 mm was used as the cut-off value for quality assurance.