Following the results of multiple randomized controlled trials demonstrating improved short-term outcomes and equivalent oncologic outcomes compared to an open approach, laparoscopic colectomy has become the operation of choice for colon cancer. However, given the technical difficulty of operating in a narrow pelvis with fixed instruments and an inability to demonstrate noninferiority compared to an open approach with respect to oncologic safety in recent randomized controlled trials, concerns regarding the feasibility, safety, and oncologic efficacy of laparoscopic resection of rectal cancer have persisted. , Given these trepidations, there has been increased adoption of a robotic approach in the surgical treatment of rectal cancer which offers the advantages of superior dexterity, enhanced operative view, and improved ergonomics through the use of multiple degrees of freedom, tremor filtration, and three-dimensional views. , With an estimated learning curve of 15 to 25 cases for experienced colorectal surgeons and a relatively low conversion-to-open rate, a robotic-assisted approach has become the minimally invasive approach of choice for low anterior resection (LAR) of rectal cancer. ,
Patient positioning, access, and pneumoperitoneum
Exploration of abdomen
Additional robotic port placement
Initiation of dissection as well as identification and preservation of hypogastric nerves and left ureter
Identification, skeletonization, and division of inferior mesenteric artery
Identification, skeletonization, and division of inferior mesenteric vein
Mobilization of descending colon and splenic flexure
Dissection along total mesorectal excision (TME) plane
Division of rectum and proximal colon
Ligation and division of colonic mesentery and specimen extraction
Perfusion assessment of planned anastomotic site
Anastomotic leak test
± Diverting loop ileostomy and drain placement
Indications and contraindications for robotic low anterior resection
Given the improved ergonomics associated with a robotic approach for pelvic dissection compared to open and laparoscopic approaches, robotic LAR is ideal for low- and mid-rectal tumors located 1 to 10 cm from the anal verge. In order to perform an LAR, a distal margin ≥1 cm from the tumor is required in order to perform a stapled anastomosis. However, for very low rectal tumors, an intersphincteric resection with a hand-sewn coloanal anastomosis or an abdominoperineal resection can still be performed with a robotic approach. As with laparoscopic surgery, the only absolute contraindication to a robotic LAR is inability to tolerate pneumoperitoneum due to hemodynamic instability or severe cardiac or pulmonary disease. Relative contraindications are extensive peritoneal adhesions from prior abdominal operations, locally advanced tumors requiring en bloc multivisceral resection, pelvic or abdominal metastasis that would be difficult to simultaneously resect with a robotic approach, and limited surgeon experience and comfort with robotic LAR.
Robotic versus open and laparoscopic approaches for low anterior resection
There are currently only a limited number of large randomized controlled trials comparing outcomes by operative approach for rectal cancer, five of which compared laparoscopic and open approaches, and only one of which compared robotic and laparoscopic approaches. In the five trials comparing laparoscopic and open approaches, length of stay was significantly shorter for a laparoscopic approach in two of the trials, , and there were no significant differences in postoperative complication rates, local recurrence rates, disease-free survival, or overall survival between the two groups in each of the studies. , , , However, operative time was significantly longer for a laparoscopic approach in each of the studies ( P > .05), , , , , and of more concern, the Medical Research Council Conventional versus Laparoscopic-Assisted Surgery in Colorectal Cancer (MRC CLASICC) trial demonstrated that a laparoscopic approach was associated with a two-fold increase in the rate of a positive circumferential margin (CRM) (12% vs. 6%), and the Australasian Laparoscopic Cancer of the Rectum (ALaCaRT) and the American College of Surgeons Oncology Group (ACOSOG) Z6051 trials revealed that laparoscopic LAR failed to meet the criteria for noninferiority with respect to a composite oncologic metric consisting of completeness of TME, CRM, and distal resection margin compared to an open approach. , While the results of these trials raised concerns regarding oncologic outcomes for laparoscopic LAR, a recent noninferiority meta-analysis that included 14 randomized controlled trials did find that laparoscopic resection was noninferior to an open approach with respect to positive CRMs, incomplete mesorectal excision, and positive distal resection margins. Therefore, a laparoscopic approach does appear safe and most likely equivalent to an open approach for resection of rectal cancer in experienced hands.
Given the concerns for oncologic inferiority for a laparoscopic approach and the increasing adoption of a robotic approach for rectal cancer given improved ergonomics, the Robotic versus Laparoscopic Resection for Rectal Cancer (ROLARR) randomized controlled trial was performed to compare outcomes between robotic and laparoscopic approaches for rectal cancer. The international, multicenter superiority trial recruited 471 patients from 29 institutions between January 2011 and September 2014. The primary study endpoint was conversion to an open approach, and secondary endpoints included perioperative complications, 30-day postoperative mortality, CRM positivity, and bladder and sexual dysfunction. The 40 participating surgeons had to perform at least 30 minimally invasive rectal cancer resections, of which ≥10 had to be conventional laparoscopic and ≥10 had to be robotic resections. While a robotic approach was associated with a lower rate of conversion to open surgery, it did not reach statistical significance (8.1% vs. 12.2%, P = .16). There were no significant differences between a robotic and laparoscopic approach with respect to CRM positivity (5.1% vs. 6.3%, P = .56), 30-day postoperative complication rates (33.1% vs. 31.7%, P = .84), 30-day postoperative mortality rates (0.8% vs. 0.9%, P = N/A due to small number of events), bladder dysfunction ( P = .27), male sexual dysfunction ( P = .75), and female sexual dysfunction ( P = .60). While the trial failed to demonstrate any significant differences in outcomes between a robotic and laparoscopic approach, a minimally invasive robotic approach appears safe and still offers the potential for earlier return of gastrointestinal function and shorter length of stay compared to an open approach.
Following an initial diagnosis of rectal adenocarcinoma, patients should undergo multidisciplinary evaluation by surgery, medical oncology, and radiation oncology. For those who are deemed potential surgical candidates based on comorbidity and functional status following a complete history and physical exam, preoperative work-up should include anorectal exam and proctoscopy to assess the distance from the anal verge to the distal extent of the tumor and the relationship between the tumor and the sphincter complex, total colonoscopy to evaluate for synchronous lesions, serum carcinoembryonic antigen (CEA) level, and magnetic resonance imaging (MRI) of the pelvis with contrast and computed tomography (CT) of the chest, abdomen, and pelvis with contrast to determine the American Joint Committee on Cancer (AJCC) clinical TNM stage. While endoscopic ultrasound of the rectum was often utilized in evaluating tumor depth and nodal status in the past, MRI is now the preferred tumor staging modality as it can accurately predict a threatened CRM, has the ability to assess for tumor deposits and vascular invasion, and is not operator dependent. Furthermore, it allows for pretreatment assessment for lateral pelvic lymph node metastasis which may be as high as 18.1% in patients with T3 or T4 lower rectal cancer. CT of the chest, abdomen, and pelvis should be obtained to evaluate for distant metastatic disease as approximately 6% of patients with rectal cancer will have synchronous lung metastasis and 12% will have synchronous liver metastasis. For suspicious liver lesions that are too small to characterize on CT imaging, MRI of the abdomen with contrast can be useful as it has a higher sensitivity than CT imaging, especially for lesions less than 1 cm. Positron emission tomography (PET)/CT can be utilized if there are equivocal findings on CT imaging but should not be routinely obtained or used as a substitute for initial CT staging scans. ,
Following the results of several randomized controlled trials, neoadjuvant chemoradiation has become the treatment standard for locally advanced rectal cancer, which is defined as clinical T3-T4b and/or clinical node-positive disease, to improve local recurrence rates. , Furthermore, “total neoadjuvant therapy” consisting of either induction systemic therapy for 12 to 16 weeks followed by chemoradiation or initial chemoradiation followed by consolidative chemotherapy have been increasingly used due to higher rates of a complete clinical and/or pathologic response and improved recurrence-free survival compared to standard neoadjuvant chemoradiation and adjuvant systemic therapy. Regardless of the neoadjuvant treatment approach, patients who receive neoadjuvant therapy should be restaged with repeat MRI of the pelvis and CT of the chest, abdomen, and pelvis prior to surgical intervention to assess treatment response, evaluate for technical resectability and a clear CRM, and rule out distant metastatic disease. Furthermore, select patients with an apparent clinical complete response following neoadjuvant therapy, characterized by no palpable tumor on examination, no visible pathology aside from a white scar on flexible sigmoidoscopy, and no evidence of disease on repeat imaging, may avoid radical resection with a “watch and wait” surveillance approach at institutions with such a protocol.
Operating room setup and operative steps
Patient preparation and positioning
If a temporary or permanent ostomy is being considered, preoperative education and stoma marking by an enterostomal therapist should be performed. Given an association between the use of preoperative mechanical and oral antibiotic preparation and decreased rates of surgical site infection across multiple studies, both the American College of Surgeons and the American Society of Colon and Rectal Surgeons recommend mechanical bowel preparation combined with preoperative oral antibiotics for elective colorectal resections. , Typical bowel preparations include mechanical bowel preparation with polyethylene glycol solution in the afternoon or evening before surgery followed by three repeated doses of oral antibiotics with neomycin and erythromycin or metronidazole over a period of approximately 10 hours. Furthermore, per national clinical guideline recommendations, patients should receive appropriate prophylactic intravenous antibiotics with activity against anaerobic and aerobic floras of the bowel within 1 hour prior to surgical incision.
Following induction of anesthesia, the patient should be placed in a modified lithotomy position with the buttocks and perineum exposed at the edge of the operating room table and the legs placed in stirrups such that the hips are flexed and slightly abducted. Both arms are tucked with the hands in a neutral position and all bony prominences adequately padded, and the patient is well secured to the operating room table to prevent body shifting during table position changes. A urinary catheter should be placed for bladder decompression, and an orogastric or nasogastric tube should be placed for gastric decompression. Rectal washout with diluted betadine solution, which has been found to reduce the risk of local recurrence in some studies presumably by reducing the burden of exfoliated tumor cells within the rectal lumen, can also be performed at this time. , Finally, if indicated, such as in cases of reoperative pelvic surgery, ureteral stents also can be placed. After appropriate positioning, the abdomen is then prepped in sterile fashion, and the operation is commenced.
Stages of the operation
Peritoneal access, abdominal exploration, and port placement
Based on surgeon preference, entry into the abdominal cavity and pneumoperitoneum may be obtained with a Veress needle in the left upper quadrant at Palmer’s point, with a visual entry technique using an optical trocar in the right upper quadrant which can later be used as an assistant port, or with an open Hasson technique through the umbilicus. A thorough exploration of the peritoneal cavity should then be performed to detect or rule out radiographically occult distant metastasis, carcinomatosis, and tumor fixation to other organs. Once a decision is made to proceed with robotic resection, the necessary four robotic ports and assistant ports are placed.
With use of the Intuitive da Vinci Xi robotic system, the standard configuration of robotic port placement should consist of a straight line from the right anterior superior iliac spine to the left subcostal margin with the robot docked at the patient’s left hip and the bedside assistant surgeon situated at the patient’s right ( Fig. 52.1 ). However, modifications may be necessary based on the patient’s body habitus or if multivisceral resection is planned. Using a linear configuration, an 8 to 12 mm right lower quadrant robotic port (port #4), is placed between the right anterior superior iliac spine and the umbilicus, which will be utilized as an instrument and eventual stapler port, an 8 mm robotic port is placed at the umbilicus (port #3), which will be used as the camera port, and two 8 mm robotic ports are placed in the left upper quadrant (port #1 and port #2), which will be utilized as instrument ports. If not already placed, an assistant port is placed in the right upper quadrant. If necessary, an additional assistant port can be placed in a subxiphoid position. The patient is then placed in 30 degrees of Trendelenburg with approximately 10 degree tilt to the right. The robot is then docked and targeted toward the pelvis. An atraumatic robotic grasper, such as a tip-up grasper or Cadiere forceps, is placed in port #1, robotic fenestrated bipolar forceps are placed in port #2, the robotic camera is placed in port #3, and either hot scissors or a hook cautery instrument is placed in port #4.