PATHOLOGICAL DEFINITION AND DIFFICULTIES IN ASSESSING POSITIVE MARGINS IN RADICAL PROSTATECTOMY SPECIMENS

Significant reduction in positive surgical margin rate after laparoscopic radical prostatectomy by application of the modified surgical margin recommendations of the 2009 International Society of Urological Pathology consensus

OBJECTIVES

To verify retrospectively the margin status and analyse the location and characteristics of positive surgical margins (PSMs) in patients undergoing radical prostatectomy (RP), by a central pathology review, based on the consensus conference 2009 updated margin criteria from the International Society of Urological Pathology (ISUP).

PATIENTS AND METHODS

The detailed PSM characteristics of 441 patients who underwent laparoscopic RP (LRP) between 1999 and 2007 were centrally reviewed with regard to location, number, Gleason score at the PSM and tumour width. Predictors of PSMs and the impact of several PSM characteristics on clinical outcomes were examined. Patient characteristics were compared using the chi-squared test. Differences in recurrence-free survival (RFS) rates were analysed using the log-rank test and presented as Kaplan-Meier survival curves. Univariable and multivariable Cox regression analysis for the prediction of RFS was performed.

RESULTS

Central pathology review using the updated PSM definition according to ISUP 2009, resulted in reclassification of a substantial number of patients with PSMs (n = 113, 26.6%) as R0. Several PSM characteristics with a higher risk of biochemical recurrence (BCR) were identified as the strongest independent predictors of RFS: pathological stage; Gleason score; and the presence of multiple PSMs (hazard ratio [HR] 1.78; 95% confidence interval [CI] 1.08-2.96; P = 0.025). Further analysis replacing the location of PSM by the width categories of PSM showed that a PSM >3 mm was an independent predictor of RFS (HR 1.72; 95% CI 1.08-2.72; P = 0.022).

CONCLUSIONS

The impact of PSMs after LRP for prostate cancer remains unclear. PSMs in the present cohort of patients undergoing LRP had different characteristics and conferred different risks of BCR. A better understanding of PSM characteristics and a careful standardized pathological evaluation is needed to adequately counsel patients with respect to prognosis and adjuvant therapy after LRP.

Light Reflectance Spectroscopy to Detect Positive Surgical Margins on Prostate Cancer Specimens

PURPOSE

Intraoperative frozen section analysis is not routinely performed to determine positive surgical margins at radical prostatectomy due to time requirements and unproven clinical usefulness. Light reflectance spectroscopy, which measures light intensity reflected or backscattered from tissues, can be applied to differentiate malignant from benign tissue. We used a novel light reflectance spectroscopy probe to evaluate positive surgical margins on ex vivo radical prostatectomy specimens and correlate its findings with pathological examination.

MATERIALS AND METHODS

Patients with intermediate to high risk disease undergoing radical prostatectomy were enrolled. Light reflectance spectroscopy was performed on suspected malignant and benign prostate capsule immediately following organ extraction. Each light reflectance spectroscopy at 530 to 830 nm was analyzed and correlated with pathological results. A regression model and forward sequential selection algorithm were developed for optimal feature selection. Eighty percent of light reflectance spectroscopy data were selected to train a logistic regression model, which was evaluated by the remaining 20% data. This was repeated 5 times to calculate averaged sensitivity, specificity and accuracy.

RESULTS

Light reflectance spectroscopy analysis was performed on 17 ex vivo prostate specimens, on which a total of 11 histologically positive and 22 negative surgical margins were measured. Two select features from 700 to 830 nm were identified as unique to malignant tissue. Cross-validation when performing the predictive model showed that the optical probe predicted positive surgical margins with 85% sensitivity, 86% specificity, 86% accuracy and an AUC of 0.95.

CONCLUSIONS

Light reflectance spectroscopy can identify positive surgical margins accurately in fresh ex vivo radical prostatectomy specimens. Further study is required to determine whether such analysis may be used in real time to improve surgical decision making and decrease positive surgical margin rates.

International Society of Urological Pathology (ISUP) Consensus Conference on Handling and Staging of Radical Prostatectomy Specimens. Working group 5: surgical margins

The 2009 International Society of Urological Pathology Consensus Conference in Boston, made recommendations regarding the standardization of pathology reporting of radical prostatectomy specimens. Issues relating to surgical margin assessment were coordinated by working group 5. Pathologists agreed that tumor extending close to the 'capsular' margin, yet not to it, should be reported as a negative margin, and that locations of positive margins should be indicated as either posterior, posterolateral, lateral, anterior at the prostatic apex, mid-prostate or base. Other items of consensus included specifying the extent of any positive margin as millimeters of involvement; tumor in skeletal muscle at the apical perpendicular margin section, in the absence of accompanying benign glands, to be considered organ confined; and that proximal and distal margins be uniformly referred to as bladder neck and prostatic apex, respectively. Grading of tumor at positive margins was to be left to the discretion of the reporting pathologists. There was no consensus as to how the surgical margin should be regarded when tumor is present at the inked edge of the tissue, in the absence of transected benign glands at the apical margin. Pathologists also did not achieve agreement on the reporting approach to benign prostatic glands at an inked surgical margin in which no carcinoma is present.