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Urinary dysfunction (UD) remains a significant complication of rectal cancer surgery. In modern surgical treatment for rectal cancer, multiple operative approaches are used. Such approaches include open, laparoscopic, and robotic-assisted surgery; and multiple procedures, including anterior, intersphincteric, and abdominoperineal resection. Thus, modern surgical treatments for rectal cancer have diversified. This study aimed to identify risk factors for early UD (EUD) after total mesorectal excision (TME) and to explore the methods for decreasing postoperative EUD in diverse surgical treatments for rectal cancer. In our retrospective cohort study, we enrolled patients with lower rectal cancer who underwent TME alone at a single high-volume cancer center between 2010 and 2017. EUD was defined as the presence of ≥ 50 mL residual urine volume. Multivariate analysis was performed to determine clinicopathological factors significantly associated with postoperative EUD. Of a total of 337 eligible patients, 32 patients (10%) had postoperative EUD. Multivariate analysis revealed that only the operative approach (laparoscopic surgery: odds ratio [OR], 8.93; 95% confidence interval [CI], 2.94–27.14, open surgery: OR, 11.55; 95% CI 2.10–63.83) was significantly associated with an increase in postoperative EUD. Robotic-assisted surgery was associated with significant reduction in postoperative EUD. Only robotic-assisted surgery was inversely correlated with postoperative EUD. Robotic-assisted surgery may be a useful approach to protect urinary function in lower rectal cancer surgery.

Although a “no-touch isolation” technique is used in colorectal cancer surgery to reduce the risk of metastatic induction, endoscopic resection (ER) prior to surgery may work against this aim. This study evaluated the effects of initial ER on short- and long-term outcomes in T1 colorectal cancer. This retrospective cohort study enrolled patients with pathological T1 colorectal cancer who underwent colorectal surgical resection at a Japanese tertiary cancer center between 2002 and 2012. A total of 548 eligible patients were divided into two groups: patients initially treated using surgical resection with lymph node dissection (LND) (primary group, n = 304) and patients treated using initial ER and additional surgical resection with LND (secondary group, n = 244). The inverse probability of treatment weighting (IPTW) method based on propensity score was used to compare postoperative complications and long-term recurrence. The incidence of postoperative complications with Clavien–Dindo classification grade ≥ II was 10.9% and 7.4% in the primary and secondary groups, respectively (p = 0.16). Multivariate analysis with a logistic proportional hazard regression model using IPTW revealed no significant differences in postoperative complications between the two groups (p = 0.79). During a median follow-up after surgery of 61.4 months, recurrence was observed in 3 (1.0%) and 8 (3.3%) patients, respectively (p = 0.06). Multivariate analysis with a Cox proportional hazard regression model using IPTW revealed no significant differences in recurrence between the two groups (p = 0.07). Our results suggest no significant adverse effects of initial ER prior to surgery on surgical complications and long-term recurrence in T1 colorectal cancer.

The optimal surgical approach for clinical T4 (cT4) rectal cancer is unknown. This study was conducted to clarify short- and long-term outcomes of robotic surgery for cT4 rectal cancer. In our retrospective cohort study, we enrolled patients who underwent robotic surgery for cT4 rectal cancer within 15 cm from the anal verge between 2011 and 2018. The short- and long-term outcomes were evaluated. Of a total of 122 eligible patients, 70 (57%) had cT4a tumors and 52 (43%) had cT4b tumors. Thirty-five patients (29%) had distant metastasis and 21 (17%) underwent preoperative chemoradiotherapy. Thirty-four patients (28%) underwent combined resection of adjacent organs and 43 (35%) underwent lateral lymph node dissection. The median operative time was 288 min and the median blood loss was 11 ml. No patients required conversion to open surgery. The incidences of postoperative complications of grades II, III, and IV or more according to the Clavien–Dindo classification were 17.2%, 3.5%, and 0%, respectively. Seventy-three patients (60%) had pathological T4 tumors, and the incidence of positive resection margins was 4.9%. The median follow-up time was 42.9 months. The 3-year overall survival, disease-free survival, and cumulative local recurrence rates were 87.5%, 70.4%, and 4.0%, respectively. The short- and long-term outcomes of robotic surgery for cT4 rectal cancer were favorable. Robotic surgery is considered to be a useful approach for cT4 rectal cancer.

Various predictors of the difficulty of total mesorectal excision for rectal cancer have been described. Although a bulky mesorectum was considered to pose technical difficulties in total mesorectal excision, no studies have evaluated the influence of mesorectum morphology on the difficulty of total mesorectal excision. Mesorectal fat area at the level of the tip of the ischial spines on magnetic resonance imaging was described as a parameter characterizing mesorectum morphology. This study aimed to evaluate the influence of clinical and anatomical factors, including mesorectal fat area, on the difficulty of total mesorectal excision for rectal cancer. This study enrolled 98 patients who underwent robotic-assisted laparoscopic low anterior resection with total mesorectal excision for primary rectal cancer, performed by a single expert surgeon, between 2010 and 2015. Magnetic resonance imaging-based pelvimetry data were collected. Linear regression was performed to determine clinical and anatomical factors significantly associated with operative time of the pelvic phase, which was defined as the time interval from the start of rectal mobilization to the division of the rectum. The median operative time of the pelvic phase was 68 min (range 33–178 min). On univariate analysis, the following variables were significantly associated with longer operative time of the pelvic phase: male sex, larger tumor size, larger visceral fat area, larger mesorectal fat area, shorter pelvic outlet length, longer sacral length, shorter interspinous distance, larger pelvic inlet angle, and smaller angle between the lines connecting the coccyx to S3 and to the inferior middle aspect of the pubic symphysis. On multiple linear regression analysis, only larger mesorectal fat area remained significantly associated with longer operative time of the pelvic phase (p = 0.009). Mesorectal fat area may serve as a useful predictor of the difficulty of total mesorectal excision for rectal cancer.

Persistent descending mesocolon (PDM) is typically asymptomatic. However, features such as adhesion and variations in vessel anatomy could affect the surgical techniques for colorectal cancer (CRC). This study aimed to investigate the frequency and radiological features of PDM. Short-term outcomes after conventional laparoscopic surgery (CLS) for CRC with PDM were also investigated to assess the feasibility of CLS and identify strategies for minimally invasive surgery (MIS) in CRC with PDM. Patients who underwent MIS, including CLS and robot-assisted laparoscopic surgery (RALS), for left-sided CRC between April 2016 and June 2019, were investigated. PDM was defined as the existence of the right border of the descending colon inside the right border of the left kidney based on preoperative computed tomography findings. Radiological findings of 837 patients were examined, and PDM was found in 19 (2.3%) patients. Radiality of the inferior mesenteric artery (IMA) was found in 5 of 19 (26.3%) PDM cases, which was significantly higher than that in non-PDM cases. The median lengths between the IMA and inferior mesenteric vein (IMV) and between the IMV and descending colon in PDM cases were 14.8 mm and 17.2 mm, respectively, which were significantly shorter than those in non-PDM cases. Short-term outcomes were evaluated only in CLS cases since the rate of hybrid surgery among RALS cases differed between non-PDM and PDM cases (0% vs. 44.4%), which would affect the surgical outcomes. The short-term outcomes in 447 CLS cases were similar between PDM and non-PDM cases. The frequency of extracorporeal division of the left colic artery (LCA) and IMV was significantly higher in PDM than in non-PDM cases (70.0% vs. 5.7%). This radiological definition of PDM was feasible. CLS for left-sided CRC with PDM was feasible, and dividing the LCA and IMV extracorporeally would be vital for safe surgery.

The aim of the present study was to clarify the advantages of robotic-assisted laparoscopic lateral lymph node dissection (RALLD) for rectal cancer by comparing its short-term outcomes with those of open lateral lymph node dissection (OLLD) in a large series from a single center. In terms of RALLD for advanced lower rectal cancer, there are only a few reports with a small number of cases in retrospective, non-comparative studies.From April 2010 to July 2014, a total of 177 patients underwent rectal cancer surgery with lateral lymph node dissection. Four patients who underwent conventional laparoscopic lateral lymph node dissection were excluded. Thus, 173 patients were enrolled, with 85 RALLD and 88 OLLD cases. Perioperative outcomes, postoperative complications, and pathological results were compared between the groups.No conversion to open surgery was necessary in the RALLD group. The rate of sphincter-preserving procedure was significantly higher in the RALLD group than in the OLLD group (p = 0.007). Operative time was significantly longer in the RALLD group than in the OLLD group (p = 0.007). Blood loss was significantly less in the RALLD group than in the OLLD group (p0.001). The rates of wound infection, small bowel obstruction, anastomotic leakage, and urinary retention were significantly lower in the RALLD group than in the OLLD group. Numbers of harvested lymph nodes and positive resection margin rates showed no significant differences.The short-term outcomes of RALLD may be superior to those of OLLD for advanced lower rectal cancer.

Few data are available to assess the learning curve for robotic-assisted surgery for rectal cancer. The aim of the present study was to evaluate the learning curve for robotic-assisted surgery for rectal cancer by a surgeon at a single institute. From December 2011 to August 2013, a total of 80 consecutive patients who underwent robotic-assisted surgery for rectal cancer performed by the same surgeon were included in this study. The learning curve was analyzed using the cumulative sum method. This method was used for all 80 cases, taking into account operative time. Operative procedures included anterior resections in 6 patients, low anterior resections in 46 patients, intersphincteric resections in 22 patients, and abdominoperineal resections in 6 patients. Lateral lymph node dissection was performed in 28 patients. Median operative time was 280 min (range 135–683 min), and median blood loss was 17 mL (range 0–690 mL). No postoperative complications of Clavien–Dindo classification Grade III or IV were encountered. We arranged operative times and calculated cumulative sum values, allowing differentiation of three phases: phase I, Cases 1–25; phase II, Cases 26–50; and phase III, Cases 51–80. Our data suggested three phases of the learning curve in robotic-assisted surgery for rectal cancer. The first 25 cases formed the learning phase.

The aim of the present study was to clarify the advantages of robotic-assisted laparoscopic lateral lymph node dissection (RALLD) for rectal cancer by comparing its short-term outcomes with those of open lateral lymph node dissection (OLLD) in a large series from a single center. In terms of RALLD for advanced lower rectal cancer, there are only a few reports with a small number of cases in retrospective, non-comparative studies. From April 2010 to July 2014, a total of 177 patients underwent rectal cancer surgery with lateral lymph node dissection. Four patients who underwent conventional laparoscopic lateral lymph node dissection were excluded. Thus, 173 patients were enrolled, with 85 RALLD and 88 OLLD cases. Perioperative outcomes, postoperative complications, and pathological results were compared between the groups. No conversion to open surgery was necessary in the RALLD group. The rate of sphincter-preserving procedure was significantly higher in the RALLD group than in the OLLD group (p = 0.007). Operative time was significantly longer in the RALLD group than in the OLLD group (p = 0.007). Blood loss was significantly less in the RALLD group than in the OLLD group (p

This observational study was conducted to compare the rate of symptomatic anastomotic leakage (AL), as defined by precise criteria, between laparoscopic and open surgery in patients with mid-to-low rectal cancer using a relatively novel statistical technique.A total of 1014 consecutive low anterior resection (LAR) patients were registered, of whom 936 were included in this prospective, multicenter, and cohort study (UMIN-CTR, Number 000004017). Patients with rectal cancer within 10 cm from the anal verge underwent either open or laparoscopic LAR at one of the 40 institutions in Japan from June 2010 to February 2013. The primary endpoint of this study was to compare the rate of symptomatic AL between the two groups before and after propensity score matching (PSM). The secondary endpoint was to analyze the risk factors for symptomatic AL in open and laparoscopic surgery.After PSM, the incidence of symptomatic AL in open and laparoscopic surgery was 12.4 and 15.3 %, respectively (p = 0.48). AL requiring relaparotomy occurred after 3.8 % of open surgeries and 6.2 % of laparoscopic surgeries (p = 0.37). Multivariate analysis identified male gender as an independent risk factor for symptomatic AL following laparoscopic surgery (p = 0.001; odds ratio 5.2; 95 % CI 2.0-13.8), and male gender (p = 0.004; odds ratio 2.6; 95 % CI 1.3-5.6), tumor size (p = 0.002; odds ratio 1.2; 95 % CI 0.7-0.9), and number of stapler firing (p = 0.04; odds ratio 4.1; 95 % CI 1.0-15.0) following open surgery.The rate of symptomatic AL was comparable following laparoscopic and open LAR in this large, multicenter, cohort study after PSM. Male gender was associated with an increased risk of symptomatic AL after laparoscopic LAR.