Pelvic dimensions as a predictor of difficulty in laparoscopic surgery for rectal cancer

Abstract

Laparoscopic surgery for rectal cancer is thought to be a technically more difficult operation than laparoscopic colectomy. Data from the Conventional versus Laparoscopic-Assisted Surgery In Colorectal Cancer (CLASICC) trial showed that circumferential resection margin positivity was greater in the laparoscopic group (12%) than in the open surgery group (6%) undergoing anterior resection, although this difference was not significant [1]. In contrast, many nonrandomized studies, including ours, have suggested that laparoscopic surgery for rectal cancer is safe and feasible with careful case selection and expertise [2, 3]. The recent randomized Comparison of Open versus laparoscopic surgery for mid and low REctal cancer After Neoadjuvant chemoradiotherapy (COREAN) trial showed that laparoscopic surgery after preoperative chemoradiotherapy for mid and low rectal cancer is safe and that the quality of oncologic resection is similar to that of open surgery [4]. Because the future may see increasing demand for laparoscopic surgery to treat rectal cancer, a better understanding of the factors associated with the difficulty of laparoscopic surgery is important for surgeons, especially those learning these operations for proper case selection. In the December issue of Surgical Endoscopy, Killeen et al. [5] examined the influence of pelvic dimensions measured by magnetic resonance imaging (MRI) on difficulties in laparoscopic surgery for rectal cancer. Operative time was used as a measurement of operative difficulty. Univariate analysis showed that a less acutely curved sacrum and a larger sagittal pelvic outlet were significantly correlated with longer operative time, especially for a pelvis with a narrow intertuberous distance. Although Killeen et al. [5] introduced our study as supportive of their findings, indeed, we came to different conclusions [6]. We showed by multivariate analysis that narrower pelvic outlet together with higher body mass index, shorter tumor distance from the anal verge, and advanced tumor depth was independently predictive of longer operative time in laparoscopic total mesorectal excision (TME) with intracorporeal rectal transection and double-stapling technique (DST) anastomosis. There may be some reasons for the different conclusions. First, the total number of patients analyzed in the study of Killeen et al. [5] was small (n = 25). Second, multivariate analysis including patientand tumor-related factors other than pelvic dimensions was not performed in their study. Third, they evaluated the total operative time as dependent variable, and patients who underwent either laparoscopic anterior resection or abdominoperineal resection were included. However, excluding the procedures outside the pelvis might be necessary for accurate analysis of the influence that pelvic dimensions has on difficulties in laparoscopic surgery for rectal cancer because pelvic dimensions influence the procedures more directly after the pelvic cavity is reached. We also have reported that narrow pelvic dimensions were not associated with overall postoperative morbidity and anastomotic leakage [6]. On the contrary, larger pelvic outlet was independently predictive of anastomotic leakage [6]. Considering these results, we concluded in our T. Akiyoshi (&) M. Ueno Gastroenterological Center, Department of Gastroenterological Surgery, Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan e-mail: takashi.akiyoshi@jfcr.or.jp