The surgical management of rectal cancer is well-established for tumours located in the upper and middle rectum. Tumours in the upper rectum are typically managed with partial mesorectal excision, whereas those in the middle rectum are treated with total mesorectal excision, both approaches aiming to preserve sphincter function. In contrast, the optimal surgical strategy for low rectal cancer remains a subject of ongoing debate and has not yet been fully standardized. Distal rectal tumours are associated with an increased risk of local recurrence, largely attributable to the technical complexity of surgical intervention 1, 2. Ultra-low rectal cancer, defined as tumours located 1 cm from the anal ring), managed with ultra-low anterior resection and hand-sewn coloanal anastomosis; Type II (juxta-anal, 1 mm from the levator ani muscles and an intact intersphincteric plane on magnetic resonance imaging (MRI) are considered suitable candidates for sphincter-preserving surgery. Conversely, ISR is contraindicated in cases with invasion of the intersphincteric plane, the external anal sphincter, or the elevator ani, in which APR would be indicated 1, 3. Relative contraindications include adverse histological subtypes such as signet ring cell carcinoma, mucinous adenocarcinoma and undifferentiated carcinoma 2. Magnetic resonance imaging is essential for both initial staging and post-treatment assessment. Current radiological guidelines emphasize the need for detailed reporting of tumour involvement of the anal canal structures, including the internal and external anal sphincters and the intersphincteric space, to guide surgical planning. Tumour extension to the levator ani, puborectalis muscle or external sphincter corresponds to T4b disease 4. Beyond the importance of accurate initial tumour staging and subsequent sphincter-preserving surgery with a low anastomosis, careful patient management and follow-up are essential to optimize functional outcomes. Low anterior resection syndrome (LARS) is a frequent long-term complication following sphincter-preserving surgery, with reported prevalence rates ranging from 34% to 49% 7. The BOREAL program was developed to address the lack of standardized management for LARS and consists of a structured, stepwise, evidence-based approach that incorporates continuous postoperative assessment using validated LARS scores 7. We present the case of a 54-year-old woman with a two-year history of rectal bleeding and unintentional weight loss. Digital rectal examination revealed a tumour located 2 cm from the anal verge, with involvement of the internal anal sphincter. Colonoscopic evaluation demonstrated an ulcerated anterior lesion extending from 0 to 4 cm from the anal verge, and histopathological analysis confirmed a microsatellite-stable (MSS) adenocarcinoma. Staging MRI identified a tumour located on the right lateral wall of the lower rectum, in contact with the right levator ani muscle (CRM = 0), with tumour invasion of the proximal internal anal sphincter, extending into the intersphincteric plane. The initial clinical stage was cT3N1cM0. Positron emission tomography/computed tomography (PET/CT) demonstrated a hypermetabolic lesion confined to the lower rectum without evidence of distant metastases. Following multidisciplinary team discussion, the patient underwent total neoadjuvant therapy (TNT), consisting of induction chemotherapy followed by chemoradiotherapy, completed in June. Two months after completion of TNT, MRI demonstrated a partial tumour response (mrTRG2), with a significant reduction in tumour volume, with persistent invasion of the internal anal sphincter and no residual involvement of the intersphincteric plane. Subsequent MRI evaluations at four and six months suggested a near-complete response; however, clinical, endoscopic, and metabolic assessments revealed residual disease. In the absence of a complete response at six months post-TNT, surgical treatment was indicated, and an organ preservation strategy was excluded. Surgical options included local excision, APR and intersphincteric resection with either delayed coloanal anastomosis (pull-through technique without ileostomy) or immediate coloanal anastomosis with a protective ileostomy. After a shared decision-making process, ISR with a protective ileostomy was selected, given its technical feasibility—supported by the absence of tumour invasion into the intersphincteric plane or pelvic floor musculature—and its oncological adequacy. This approach was complemented by the planned implementation of the BOREAL rehabilitation program for postoperative functional management. The procedure was performed using a robotic-assisted approach. The patient was positioned in Trendelenburg with a right-sided tilt. Four 8-mm robotic trocars were placed in a diagonal configuration, along with two assistant ports, and a low-pressure pneumoperitoneum was established. A robotic total mesorectal excision (performed according to the PAL technique: posterior–anterior-lateral ordered dissection) with lymphadenectomy of the inferior mesenteric artery was carried out (Video 1). Posterior mesorectal dissection was performed with preservation of the left ureter and bilateral hypogastric nerves, continuing distally to the level of the pelvic floor. Upon reaching the upper anal canal, posterior dissection was carried out to identify the levator ani muscle, which is continuous with the external anal sphincter (striated, circular fibres). Dissection was then continued until the internal sphincter (smooth, longitudinal fibres) was identified, allowing the dissection into the intersphincteric plane. Dissection then proceeded along the intersphincteric plane laterally and anteriorly. Once this plane was adequately developed—particularly posteriorly and laterally—the anterior intersphincteric dissection was completed via a perineal approach to optimize margin control. Adequate colonic reach to the pelvis was then confirmed, a diverting ileostomy was created, and the procedure proceeded with the perineal phase. A Lone Star retractor was placed. After visualization of the distal tumour margin anteriorly, circumferential mucosal markings were performed. Close communication with the anaesthesiologist was essential during the perineal approach to ensure adequate anal relaxation. Retraction of the mucosa confirmed the correct intersphincteric plane. In this case, due to the tumour location, a partial posterior intersphincteric resection and a total anterior intersphincteric resection were performed. Upon reaching the intersphincteric space, which connects with the abdominal dissection, dissection continued along the posterior plane and both lateral sides. This avascular plane was dissected using scissors. The total anterior intersphincteric dissection was left for last, carefully visualizing the external anal sphincter with the aid of two retractors. Once the intersphincteric space was fully dissected, the anal mucosa was closed to reduce the risk of contamination, and specimen exteriorization was performed. Adequate perfusion of the proximal colon was verified prior to transection. A hand-sewn end-to-end coloanal anastomosis was constructed using interrupted 3–0 Vicryl sutures, followed by the creation of a diverting ileostomy. No intra-abdominal drain was placed. Histopathological examination revealed a low-grade adenocarcinoma without high-risk features. The circumferential resection margin was negative (>1 mm), and no lymph node metastases were identified (0/20), corresponding to a final pathological stage of ypT2N0R0. Based on these findings, a surveillance strategy was recommended. The postoperative course was uneventful, and the patient was discharged on postoperative day 2. At one-month follow-up, she reported mild pain and minimal, self-limited rectal bleeding. Closure of the ileostomy was scheduled for two months after surgery, and the patient was enrolled in the BOREAL rehabilitation program for ongoing management of LARS symptoms. Barbara Noiret: Conceptualization. Quentin Denost: Methodology; validation; supervision. Irene Maya: Writing – original draft; writing – review and editing. The authors have nothing to report. None declared. This study was performed in agreement with the Declaration of Helsinki. The patient provided written informed consent for the publication. The data that support the findings of this study are available from the corresponding author upon reasonable request.
Maya et al. (Wed,) studied this question.