Johnny K Chau, MD, Joshua Soloman, A. Sender Liberman, MD, Patrick Charlebois, Barry Stein, MD, Lawrence Lee, MD, PhD. McGill University
Introduction: High-quality surgery is essential for optimal oncologic outcomes in rectal cancer, but total mesorectal excision (TME) can be difficult for mid- and low-rectal cancers. Preoperative identification of patients at risk for difficult TME may change the operative approach. The objective of this study was to determine if MRI/CT pelvimetry can predict poor quality surgery in patients undergoing laparoscopic low anterior resection (LAR) for mid- and low-rectal cancer. These patients may benefit from a transanal approach to the TME.
Methods: All patients undergoing laparoscopic LAR for rectal cancer less than 9 cm from the anal verge at a single tertiary care referral centre from 2011-2017 were retrospectively reviewed. Pelvic dimensions were measured from preoperative staging MRI/CT on sagittal (Figure 1) and axial views. Pelvimetry variables were all dichotomized based on median values. Factor analysis then identified the most relevant variables. The primary outcome was poor-quality resection, defined as an incomplete mesorectal grade, or involved circumferential (CRM) or distal (DRM) resection margins.
Results: There were 92 patients included in this study, of which 70% (64/92) were male, mean body mass index was 26.0 kg/m2 (SD 4.5), and mean tumor height was 6.7 cm (SD 1.9). Preoperative radiotherapy was administered in 70% (64/92), and the pathologic T-stage was T3/T4 in 40% (37/92). The overall incidence of poor-quality resection was 17% (16/92), including 13% (12/92) incomplete TME, 7% (9/92) involved CRM, and 1% (1/92) involved DRM. Factor analysis identified S1-pubic symphysis (line AE in Figure 1), S5-pubic symphysis (line BD), S1-S5 (line AB) distances, and angle between S1-S5-pubic symphysis (angle ABD) as uncorrelated variables. After adjusting for male gender, body mass index, and tumor height, only S1-S5-pubic symphysis angle ³74.2o (OR3.62, 95%CI 1.04-12.66) independently predicted poor quality resection.
Conclusions: MRI/CT pelvimetry can identify patients at risk for a poor-quality resection after laparoscopic LAR for mid- and low-rectal cancer. These patients may benefit from a transanal approach to improve the quality of surgical resection.
Figure 1 – Sagittal pelvimetry legend
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 93955
Program Number: S060
Presentation Session: Colorectal II – Neoplasia
Presentation Type: Podium