The impact of distance to closest negative margin on survival after pelvic exenteration.

OBJECTIVE

To determine the effect of distance to closest negative margin on survival after pelvic exenteration (PE).

METHODS

In this retrospective analysis of PE at Moffitt Cancer Center from 2000 to 2019, baseline characteristics, clinical details, and outcomes were ascertained. Distance to closest negative margin was measured. Close and distant negative margins were defined as <3 mm and ≥3 mm from malignancy to nearest surgical margin, respectively. Overall survival (OS) and progression-free survival (PFS) were determined, and Kaplan-Meier curves were compared. Cox proportional hazards regression was used to examine the association of margin status with OS and PFS.

RESULTS

Of 124 PEs with malignancy, 80 (64.5%) had negative margins. Median survival was 62 (95% confidence interval [CI] 27-70) months for negative and 21 (95% CI 15-29) months for positive margins. Of 76 with negative margins and documented margin length, 26 had close and 50 had distant margins. Median survival was 32 (95% CI 14-62) months for close and 111 (95% CI 42-166) months for distant margins. Distant margins were associated with improved OS (p = 0.0054) and PFS (p = 0.0099) compared to close margins. After adjusting for other prognostic factors, patients with distant margins had significantly decreased risk of all-cause mortality (HR 0.39, 95% CI 0.19-0.78; p = 0.008) and progression (HR 0.48, 95% CI 0.23-0.99; p = 0.04) compared to positive margins. No significant differences in OS or PFS were observed between close and positive margins. This survival benefit remained among those with cervical cancer. Median survival in this cohort was 34.1 (95% CI 2.0-69.8) months for close and 165.7 (95% CI 24.5-165.7) for distant margins.

CONCLUSIONS

Distant margins following PE are associated with improved OS and PFS compared to close margins.