Transanal total mesorectal excision : a novel approach to the distal rectum

Abstract

Rectal cancer surgery has undergone a major breakthrough over the past 30 years. Due to the anatomical confines of the deep pelvis, resection of the rectum is still technically challenging. Transanal total mesorectal excision (TaTME) is a bottom-to-up approach (via the anus) to the pelvis, which is exactly the opposite of the conventional transabdominal top-to-bottom approach (via the abdominal cavity). Its potential advantages are better visualization and more precise dissection. This would hopefully translate into better oncological clearance and postoperative urogenital and anorectal function. The objective of this thesis was to investigate the use of TaTME in the treatment of rectal cancer. A comparison of TaTME and robotic-assisted total mesorectal resection (RaTME) showed that TaTME was associated with shorter operating time (254 vs. 170 min, p<0.05) and less blood loss (50 vs. 150ml, p=0.002). There was no difference in the distal margin, the number of lymph nodes examined, and the rate of positive circumferential resection margin (0 vs. 5%, p=0.494). TaTME was associated with earlier recovery of urinary function at 6 months post-surgery and less severe urinary dysfunction at 12 months (3.1% vs 17.6%, p=0.026). Patients in the TaTME group had no deterioration in the quality of life (QoL) from urinary symptoms, whereas QoL recovered only after 6 months in the RaTME group. Overall, patients in the TaTME group had better urinary symptoms-related QoL at 6 and 12 months after surgery. For sexual function, both groups had significant deterioration after surgery, but patients in the TaTME group recovered at 12 months while those in the RaTME group had persistent poorer sexual function scores one year after surgery. Patients who underwent TaTME had worse Low Anterior Resection Syndrome (LARS) at 3 after surgery, compared to the conventional approach. However, there was no difference in terms of LARS severity and fecal incontinence from 6 months onwards. The use of TaTME with single-incision laparoscopy was associated with minimal postoperative pain, similar oncological clearance and reasonable operating time, median 247.5 minutes (range: 188- 462 minutes). A model was developed to predict difficult double-stapling technique (DST), i.e. transecting the rectum with three or more stapler cartridges, in the conventional TME approach. TaTME can be used when difficult DST is expected. In conclusion, TaTME is a promising technique. It achieves similar oncological clearance. There was a faster recovery of urinary and sexual dysfunction after surgery. LARS and faecal incontinence might be worse especially in the initial postoperative period. It can be used in conjunction with single-incision laparoscopy to further reduce postoperative pain.