Complete or incomplete bowel obstruction presents as the first symptom in approximately 20% of colorectal cancer patients, and Lee et al. have reported that the frequency of MRO is approximately one third of that of malignant left colonic obstruction [4]. Traditionally, emergency surgery without preoperative decompression, accompanied by stoma formation, has been the most common treatment strategy for MCO [5]. Recently, preoperative nonsurgical decompression such as placing an SEMS for MCO has been increasingly performed, with accumulated studies reporting that SEMS placement is effective for decompression and can be a bridge to elective surgery; this approach has reduced perioperative morbidity and mortality with a significantly increased success rate for one-stage anastomosis [1, 6].
Use of laparoscopic surgery and one-stage anastomosis for MCO has been controversial because of the high morbidity due to edematous, fragile bowel and insufficient intraabdominal working space as a result of the distended bowel [7]. However, recent studies have concluded that preoperative decompression using SEMS and transanal drainage tube is helpful when performing subsequent elective laparoscopic surgery and one-stage anastomosis [8]. Preoperative decompression of the distended bowel increases intraabdominal working space during surgery and reduces bowel edema, leading to greater safety during one-stage anastomosis [1, 9].
On the basis of this knowledge, we thought that RALS as well as conventional laparoscopic surgery can be safely performed after the decompression for MRO. In Japan, since April 2018, the procedure has been covered under insurance, resulting in an increased and widespread use of RALS for rectal cancer treatment. In general, RALS has an edge over conventional laparoscopic surgery due to the former’s ability to allow delicate operations with a stable operating view of the deep and narrow pelvis with the three dimensional (3D)-view scope and the flexible instruments on the robot. We expected these advantages to lead to a safer rectal surgery, and therefore, we selected RALS over conventional laparoscopic surgery.
Although the feasibility of laparoscopic resection of pT4 rectal cancer has recently been reported, enough evidence for the using of conventional laparoscopic surgery for advanced-stage rectal cancer is still lacking [10]. Touching the tumor with laparoscopic instruments during surgery should be strictly avoided based on the “no touch” principle; this is one of the reasons why the use of laparoscopy for advanced-stage colorectal cancer remains controversial [11]. Articulated flexible robotic instruments could impart safety during surgery by avoiding contact with the tumor. Indeed, Crolla et al. have recently reported the feasibility of robot-assisted laparoscopic resection of clinical T4b tumors of the distal sigmoid and rectum [12].
In robot-assisted partial nephrectomy (RAPN) for renal tumors, articulated flexible instruments allow approach to the tumors from all directions with extremely useful visibility offered by 3D-vision scope so as to secure definitive surgical margin from the tumor, thereby reducing positive surgical margin [13]. In our patient with advanced MRO, tumor invasion into the right ureter was suspected on the basis of preoperative CT findings, and RALS provided a definitive negative surgical margin avoiding any injury to the ureter; thus, we could benefit from the advantages conferred by the robot-assisted surgery, similar to RAPN over conventional laparoscopic surgery. In fact, the malignant rectal tumor was resected without excess or insufficient margins, preventing any injury to the right ureter.
In our patient, who had bladder–rectal disorder, Hartman’s procedure, without reconstruction, was selected not only due to the patient’s condition but also because of his performance status and age. Because of these reasons, we did not perform one-stage anastomosis without covering stoma formation, although the resected specimen showed improved intestinal edema and its feasibility is expected in RALS as well as in conventional laparoscopic surgery for MRO after SEMS placement [1, 8].
There are some limitations of the study. First, the insertion of SEMS for MRO has several drawbacks. One of which is the location of implanted SEMS. Fortunately, the present case involved the upper rectum; the insertion of SEMS in the middle and lower rectum is still controversial. To date, SEMS placement is considered unsuitable for MRO near the anal verge (i.e., within 5 cm), given the potential of anal pain, foreign body sensation, tenesmus, and incontinence because of rectal irritation by the stent [14, 15]. Recently, Lee et al. reported the efficacy and safety of SEMS placement for MRO, including six bridges in the surgical cases of lower rectal obstruction 5 cm or less distant from the anal verge [4]. However, to obtain an appropriate distal margin of 2 cm or more during curative operation for lower rectal cancer, SEMS placement for MRO near the anal verge (i.e., within 5 cm) must be carefully considered. Second, one of drawbacks of robotic surgery is the absence of tactile sensation. Operators acquire only visual information and should proceed with the operation based on the visual information. Although we think that the visual information complements the absence of tactile sensation to a certain extent, the operator should pay greater attention to the exposure of the surgical field with SEMS-inserted organ during RALS than that during a conventional laparoscopic surgery for advanced rectal cancer, strictly based on the “no touch” principle. These points must be considered by surgeons when deciding an appropriate treatment.
Our results show that RALS after SEMS placement is a safe and feasible therapeutic strategy for MRO, allowing sufficient preoperative decompression using SEMS. This approach creates working space during RALS and improves intestinal edema. Further studies are expected to establish the superiority and feasibility of RALS after SEMS placement for MRO over other approaches.
