- This retrospective study focused on evaluating how anterior vs. posterior positive surgical margins (PSM) after radical prostatectomy affected the outcome in 391 patients with prostate cancer
- Patients with apex PSM had the best prognosis in terms of biochemical recurrence (BCR) among all groups. Patients with anterior PSM showed similar clinicopathologic characteristics and similar prognosis in terms of biochemical recurrence (BCR) as those with apex PSM
- Certain clinicopathologic characteristics were significantly less favorable in patients with posterior PSM than in those with anterior PSM
- Patients with posterior PSM were at significantly higher risk of BCR when compared with patients with apex PSM on multivariate analysis (HR, 1.92; 95% CI, 1.28–2.90; P=0.002)
- Physicians may wish to consider advanced treatment options, including further adjuvant treatment, for patients with posterior PSM
After radical prostatectomy for prostate cancer (PCa), pathologists should categorize the location of positive surgical margins (PSM) as posterior, posterolateral, lateral anterior at either apex, mid or base, according to guidelines of the International Society of Urological Pathology. However, before these recommendations were published—and even afterward—so many different PSM location groups were used in research that the prognostic impact of anterior and posterior PSM has been unclear.
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Shulin Wu, MD, PhD, lab manager of the Urology and Pathology Research Laboratory at Massachusetts General Hospital, Chin-Lee Wu, MD, PhD, associate pathologist and director of Genitourinary Pathology Services at Mass General and the Mass General Cancer Center, and colleagues addressed this issue using a well-defined cohort with very long-term follow-up (median 12.6 years). In the American Journal of Clinical Oncology, they report that patients with PSM in posterior peripheral areas of prostatectomy samples had a worse prognosis than those with PSM at the apex. However, patients with PSM in anterior peripheral areas had a similar prognosis as those with PSM at the apex. This finding suggests that posterior PSM carried a worse prognostic impact than anterior PSM.
The research team reviewed data on 391 patients who underwent radical prostatectomy for localized prostate cancer between 1993 and 2007. PSM were located at the apex in 115 patients (29%), the bladder neck in 19 (5%) and peripheral areas in 257 (66%).
Focusing on the 257 patients with PSM in peripheral areas, the researchers found that 58 (15% of all patients) had anterior PSM, 174 (45% of all patients) had posterior PSM and 25 (6% of all patients) had both.
Compared with patients who had posterior PSM, patients with anterior PSM had significantly:
- Higher preoperative PSA (6.7 vs. 5.4 ng/mL, P=0.004)
- Lower greatest percentage of positive biopsy core (15% vs. 40%, P=0.01)
- Higher frequency of non-dominant on anterior/posterior distribution (68% vs. 47%, P<0.001)
Patients with anterior PSM and apex PSM had similar clinicopathologic characteristics.
Patients with apex PSM had the best prognosis in terms of biochemical recurrence (BCR) among all groups.
Compared with patients who had apex PSM, the chance of BCR was:
- Similar in patients with anterior PSM, especially those with low- to intermediate-risk disease (Gleason score ≤7)
- Significantly greater in patients with:
- Posterior PSM (HR, 1.89; P=0.001)
- Both anterior and posterior PSM (HR, 2.88; P=0.001)
- Bladder neck PSM (HR, 2.35; P=0.02)
The prognosis did not differ significantly between patients with anterior PSM versus posterior PSM, but posterior PSM was an independent prognostic factor on multivariate analysis when compared with apex PSM (HR, 1.92; 95% CI, 1.28–2.90; P=0.002).
Guidance for Physicians
These results suggest prostate cancer patients with posterior PSM have the more aggressive disease than those with anterior PSM. Previous studies reported that the anterior dominant PCa was with different pathological features and oncological prognosis when compared with posterior dominant PCa but the conclusion remains unclear. Current results may hint a favorable clinicopathological features of anterior dominant PCa when compared to posterior dominant PCa. Physicians may wish to consider advanced treatment options, including further adjuvant treatment, for patients with posterior PSM.
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