[An initial exploration of the application of transanal endoscopic microsurgery in rectal cancer patients with clinical complete response after neoadjuvant chemoradiotherapy]

Objective: To preliminarily explore the value of transanal endoscopic microsurgery (TEM) in rectal cancer patients with clinical complete response (cCR) following neoadjuvant chemoradiotherapy (nCRT). Methods: Using descriptive case series method, Clinical data of 13 patients who met the criteria of nCRT and were considered to be cCR after MRI or CT scanning, digital rectal examination and colonoscopic biopsy, as well as no lymph node or distant metastasis were found, then underwent TEM from 2013 to 2016 at the Department of General Surgery of Peking Union Medical College Hospital were collected retrospectively. A 3-course combination of capecitabine and oxaliplatin (XELOX) was used for chemotherapy. Besides, a 6MV-X ray radiation was used as radiotherapy simultaneously. Six to eight weeks after completion of radiotherapy, a preoperative assessment was carried out with intrarectal ultrasound, MRI, or pelvic abdominal CT examination. TEM was performed afterwards with informed consent. Postoperative pathological findings and follow-up results were used to evaluate the value of diagnosis and treatment of TEM on those patients. Results: There were 8 males and 5 females with a median age of 63 (27-80) years. Preoperative examination showed that the lesions were located in the anterior wall in 3 cases, the posterior wall in 3 cases, the left side wall in 4 cases, and the right side wall in 3 cases. Before nCRT, the distance between tumor and anal margin was (4.8±1.1) (2.0-7.5) cm; after nCRT, this distance was (5.2±1.3) (3.0-7.5) cm. All the 13 patients underwent extended local resection of rectal cancer via TEM with the placement of urethral catheter. The average operative time was (52.2±3.7) (42-70) minutes, and the average intraoperative blood loss was (19.2±2.8) (5-30) ml. All the patients could engage in daily activities on postoperative day 1, and could cater themselves orally on postoperative day 2. The main discomfort was postoperative anal pain and foreign body sensation (n=5), which could be alleviated by non-steroidal anti-inflammatory drugs. One case had postoperative lung infection and was cured by antibiotic treatment. One case had urinary retention after removing urine catheter, and then a urine catheter was re-inserted. Average postoperative hospital stay was (2.8±2.4) (2-12) days. All specimens were completely resected via TEM. Histopathological examination confirmed that 7 specimens had achieved pathologic complete response (pCR) and the other 6 specimens had obtained partial tumor response of CAP grade 2. Seven patients with pCR received a median follow-up of 24 (8-48) months and no local recurrence or distant metastasis was reported during follow-up period. Among these 7 cases, one developed defecation dysfunction after discharge, mainly for defecation pain and even dare to defecate, who returned to normal defecation within 2 months after surgery; One developed severe anal pain within six months after surgery and the pain disappeared after symptomatic pain relief. The other 6 patients with CAP grade 2 refused to undergo further radical operation because of their strong desire in preserving anus, and received remedial adjuvant chemotherapy instead. Conclusion: For rectal cancer patients with cCR after nCRT, TEM does have certain application values if the patient has a strong desire to preserve anus.