Does Discontinuous Involvement of a Prostatic Needle Biopsy Core by Adenocarcinoma Correlate With a Large Tumor Focus at Radical Prostatectomy?

Abstract

When prostate needle biopsies are involved discontinuously by tumor, no consensus remains on the optimal method of tumor quantification. We investigated whether discontinuous biopsy involvement usually results from a large tumor focus or multiple small foci. Prostate needle biopsies with discontinuous tumor and corresponding whole-mounted radical prostatectomies from 2008 to 2013 were analyzed. Linear length and percentage of biopsy involvement were measured both including and subtracting the benign intervening tissue. The corresponding region of the prostatectomy specimen was evaluated for tumor size and multifocality. From over 800 biopsy sets and 400 prostatectomies performed annually, 40 patients met inclusion criteria. Excluding benign tissue, length and percentage of biopsy involvement ranged from 1 to 7 mm and 5% to 66% (median 2.5 mm, 20%), whereas including intervening tissue yielded 4 to 15.5 mm and 25% to 100%, (median 7 mm, 70%), respectively. Benign intervening tissue measured from 2 to 10.5 mm (median 3.5 mm). In 31 patients (78%), a single tumor focus was present in the corresponding region of the prostate (the dominant tumor in 25/31). In 9 patients, multiple small foci were present. Eleven patients could have been excluded from active surveillance eligibility by measuring tumor from end to end (>50% involvement), of whom only 1 met criteria for clinically insignificant cancer at prostatectomy. Discontinuous tumor in a prostate biopsy often results from a single tumor focus in the corresponding region of the prostate (78%). Therefore, we recommend that an end-to-end measurement be provided, with accompanying diagnostic comment that this often correlates with the size of a single tumor focus.

Continuous versus discontinuous tumor involvement: A dilemma in prostate biopsy quantitation

“…They found that the presence of discontinuous tumor foci on biopsy was significantly more likely to correlate with actual bilateral disease. Meanwhile, Arias‐Stella et al demonstrated that discontinuous cancer foci in core biopsy represented a single tumor nodule in 31 (78%) of 40 radical prostatectomy specimens.…”

“…Several previous studies have attempted assessing the utility of different measurements of tumor extent in prostate biopsies where discontinuous cancer foci are present . Some of these studies have demonstrated that linear measurement in biopsy specimens better correlates with radical prostatectomy findings, such as the presence of extraprostatic extension and positive surgical margins.…”

“…Several previous studies have attempted assessing the utility of different measurements of tumor extent in prostate biopsies where discontinuous cancer foci are present. [3][4][5][6][7] Some of these studies have demonstrated that linear measurement in biopsy specimens better correlates with radical prostatectomy findings, such as the presence of extraprostatic extension and positive surgical margins. However, the impact of additive versus linear quantifications in prostate biopsies on predicting the actual tumor extent, including tumor volume, and patient outcomes has not been comprehensively determined in each study.…”

Essential Updates in Grading, Morphotyping, Reporting, and Staging of Prostate Carcinoma for General Surgical Pathologists

“…Some authors recommend measuring the separate tumor foci end to end, and that includes the intervening benign glandular tissue in a core, instead of adding or ''collapsing'' the separate tumor foci ( Figure 10). [83][84][85][86][87] The end-to-end measurement has been shown by some studies to be more predictive of stage and risk for margin positivity at RP. The discontinuous tumor foci in the biopsy core are often the result of a single tumor from the corresponding region of the prostate.…”

Clonal evaluation of prostate cancer molecular heterogeneity in biopsy samples by dual immunohistochemistry and dual RNA in situ hybridization

“…In general, a common approach is to assume that discontinuous foci in a single biopsy represent a large, irregularly-shaped tumor. (27,28) However, some data support clonally different tumors. (26) Given that tumor volume percentage is a critical parameter used in the selection of prostate cancer management options such as active surveillance, enabling the assessment of clonal differences in the foci in cores with discontinuous foci may be important.…”