Is Previous Transanal Endoscopic Microsurgery for Early Rectal Cancer a Risk Factor of Worse Outcome following Salvage Surgery A Case-Matched Analysis

Introduction: Transanal endoscopic microsurgery (TEM) is a minimally invasive procedure which allows local excision of early-stage rectal cancer and can be used as an alternative treatment to radical surgery. Patients can undergo salvage total mesorectal excision (sTME) following TEM after finding of unfavourable histological features. This study aimed to compare results and possible complications of sTME following TEM and primary TME (pTME) procedures. Methods: Between 2010 and 2017, early sTME was performed in 9 patients at the National Cancer Institute in Vilnius, Lithuania. These patients were compared with 18 patients who underwent pTME, matched according to gender, age, cancer stage, and operative procedure. Data were obtained from the patients' charts and reviewed prospectively. We recorded the demographics, tumour specifications, treatment, operation time, postoperative results complications, and oncological outcome. Fisher's exact test and student's T test was used to compare both groups. Results: A total of 130 patients underwent TEM at our institution during the study period, of which 9 (6.92%) had to undergo sTME. The average age of the patients was 62.7 +/- 7.07 years; 44.4% of the patients were male and 55.6% female. The average tumour size in the sTME group was 2.8 +/- 1.05 cm (range 1.5-5) and 2.61 +/- 1.36 cm (range 1-5) in the pTME group (p = 0.696). When comparing postoperative complications, statistically significant results were not found in either of the groups (p = 0.55). Operation time of pTME was significantly shorter on average, i.e. 43 min, compared to sTME (p < 0.0267). The average number of harvested lymph nodes was 12.44 +/- 7.126 in the sTME and 12.5 +/- 8.06 in the pTME group (p = 0.986). The circumferential resection margin (CRM) was negative in 92.6% (25/27) of specimens, while the CRM was positive in 2 cases (7.4%), both of which were from the sTME group. The average follow-up time was 22.8 months (8-80 months) for patients undergoing sTME and 19.33 months (2-88 months) for patients after pTME (p = 0.71). Conclusions: TEM is a relatively safe method for treating patients with early rectal cancer without high-risk features. It can be used in exceptional cases with high-risk features when the patient is not fit for radical surgery.