Transanal Endoscopic Microsurgery Versus Total Mesorectal Excision in ypT0-1 Rectal Cancer after Preoperative Radiochemotherapy: Postoperative Morbidity, Functional Results, and Long-term Oncologic Outcome

BACKGROUND: In patients with locally advanced extraperitoneal rectal cancer, a multidisciplinary approach represents the standard treatment. However, considering the favorable prognosis in patients with major or complete response, radical surgery might represent overtreatment. OBJECTIVE: This study aimed to evaluate postoperative short-term morbidity, functional outcome, and oncologic long-term outcome in patients with rectal cancer treated with local excision by transanal endoscopic microsurgery or radical surgery and to determine who achieved a complete or major pathological response (ypT0-1) after neoadjuvant treatment. DESIGN: This was a retrospective study. SETTING: The study was conducted at a single center. PATIENTS: Patients who had received neoadjuvant treatment by local excision with a major or complete pathological response at histological examination (transanal endoscopic microsurgery group) were compared to patients treated by radical surgery with the same pathological response (total mesorectal excision group). INTERVENTIONS: The interventions included local excision by transanal endoscopic microsurgery and radical surgery with total mesorectal excision. MAIN OUTCOME MEASURES: Postoperative short-term morbidity, functional outcome 1 year after surgery, and oncologic long-term outcome were measured. RESULTS: Ninety-three patients were included in the study (35 in the transanal endoscopic microsurgery group and 58 in the mesorectal excision group). In the total mesorectal excision group, a sphincter-saving approach was possible in 89.7% (vs 100%; p = 0.049); a protective temporary stoma was necessary in 74.1% of radical procedures (vs 0%; p < 0.001), and 13.8% of these became permanent. Short-term postoperative morbidity was lower after local excision (14.3% vs 46.6%; p = 0.002). One year after surgery, the transanal endoscopic microsurgery group recorded better evacuation and continence function than the total mesorectal excision group. Oncologic outcome was similar between the groups. LIMITATIONS: This study had a retrospective design. CONCLUSION: If a major or complete pathological response occurs after neoadjuvant treatment, an organ-sparing approach by local excision seems to offer the same oncologic results as radical surgery, but it has a better postoperative morbidity rate and better functional results.