Prognostic Value of Microscopic Linear Length and Gleason Score of the Tumor at Positive Margin in Robot Assisted Radical Prostatectomy Specimens: A Study of 127 Whole Mount Cases
Umar B, Alhamar M, Taneja K, Diaz-Insua M, Williamson SR, and Gupta N. Prognostic Value of Microscopic Linear Length and Gleason Score of the Tumor at Positive Margin in Robot Assisted Radical Prostatectomy Specimens: A Study of 127 Whole Mount Cases. Lab Invest 2018; 98:396.
Background: Localized prostate cancers (PCa) are usually treated with radical prostatectomy (RP) to improve cancer specific survival. Presence of positive surgical margins (PSM) is an independent prognostic factor as well as a reason for adjuvant therapy. Currently there is heterogeneous data about the significance of extent of PSM. Some studies have used the term focal and extensive and others have done exact quantification of the PSM. Some studies have questioned if extent of positive surgical margin provides any additional prognostic significance. On this background, we wanted to assess the correlation of linear length of PSM in RP specimens with the risk of biochemical recurrence (BCR). In addition, we also evaluated other pathologic parameters such as Gleason score (GS) of the tumor at the positive margin, location of positive margin, and positivity within or outside of the prostatic capsule. Design: We reviewed 127 cases of PCa with PSM on patients who underwent RP at our institution between 2012-2014. Microscopic linear length (LL) of positive margin was measured and cases were stratified as follows, LL <1mm, 1-3mm and >3mm. Following parameters were also assessed: Gleason score and stage of the main tumor, tumor volume, location of positive margin, GS at the positive margin, capsular incision with positive margin (CI) versus extraprostatic extension with positive margin (EPE-M). Results: After pathologic review, 127 patients were grouped as follows, 1. 26 with LL of <1mm, 41 with LL of 1-3 mm and 60 with LL of > 3. During the 4.5 years of follow up 0, 9, 20 patients had BCR in each group respectively. Our data suggest that LL is associated with an increased risk of BCR (p<0.001) (table 1). 2. Patients were further stratified according into two groups: CI and EPE-M, and association between LL and BCR was retained for EPE-M (p=0.036) but did not exist for CI (p=0.432). 3. Statistical significant association was also found between increasing GS of the tumor at margin and BCR (p=0.001). (table 2) 4. Apex was the most common positive margin (49%) and three fourths of the PSM were present in posterior half of prostate gland. No significant associations were seen in location of PSM and BCR. Conclusions: In summary, linear length of positive surgical margin and Gleason score of the tumor at margin are significant predictors of biochemical recurrence in radical prostatectomy specimens. EPE-M carries worse prognosis than CI. We recommend reporting these three margin parameters in RP cases with PSM. (Table Presented).