Length of prostate biopsy cores: does it impact cancer detection?

The detection of prostate carcinoma relies on adequate sampling. We aimed to evaluate whether core length is a significant biopsy parameter in the detection of cancer, especially in the low risk cancer category group.

We retrospectively analyzed pathology reports of 197 patients (2196 biopsy cores) undergoing initial transrectal ultrasound guided biopsy. A multivariate analysis of age, total prostate-specific antigen (PSA) concentration, prostate gland volume, total number of cores and length of biopsy cores was performed. Secondary analyses included stratification by Gleason score. Single core analysis was done to calculate a workable cut off value for core length with optimal sensitivity and specificity in carcinoma detection.

Mean age, PSA, prostate volume, and total number of cores were 66.9 years, 12.6 ng/mL, 47.2 cc and 11.1 cores, respectively. Whereas detection of cancer was significantly associated with advanced age (p < 0.01) and smaller prostate volumes (p < 0.001), PSA levels (p = 0.40) and number of cores (p = 0.20) were not significant predictive factors. Assessment of biopsy core lengths showed that cores harboring cancer (n = 307, average length 14.1 mm) were significantly longer than benign cores (n = 1889, average length = 13.2 mm) (p < 0.001). Core length analysis yielded 13 mm cores have an optimal sensitivity (42.8%) and specificity (76.5%) for detection of carcinoma (odds ratio: 2.43). Secondary analyses of Gleason score did not show any difference with respect to core length.

This study suggests that core length is a biopsy parameter that affects detection of cancer and is an essential parameter for core biopsy quality.