Transanal endoscopic microsurgery in early rectal cancer: time for a trial?

OBJECTIVE The optimal aim of oncological surgery is to balance cancer outcomes with preservation of function and quality of life. Radical resection (RR) offers the best curative procedure in colorectal cancer but at significant morbidity. Transanal endoscopic microsurgery (TEM) offers an alternative with less morbidity and better function. Its role remains unclear and needs to be established in the light of new emerging trends in rectal cancer. This review aims to evaluate the use of TEM and its limitations. METHOD PubMed and MEDLINE search was performed. RESULTS Strongest level of evidence (Level II) favoured TEM over RR and laparoscopic resection in term of mortality and morbidity. There was no difference in recurrence at follow-up of 41 and 56 months but neither study was adequately powered to detect a difference in recurrence/survival. Three retrospective case comparisons (Level III) also favoured TEM over RR but were subject to selection bias. Twenty eight published case series (Level IV) reported varying results due to different cancer stages, study population, full excision, adjuvant therapy and treatment indication. The oncological outcomes in TEM are similar to RR in highly selected cases but with far less mortality (near 0%), morbidity, blood loss, hospital stay and genitourinary/gastrointestinal dysfunction. TEM alone (+/- adjuvant therapy) appears sufficient for 'favourable' T1 tumours. 'Unfavourable' T1 or T2 tumours require adjuvant treatment. TEM should only be used for palliation in T3+ cancers. Seven functional studies reported significant transient dysfunction following TEM with full clinical recovery within a year. TEM is cost-effective providing sufficient cases are performed. CONCLUSION Significant heterogeneity limits conclusions from current literature. A trial is required. Alternate end-points to local recurrence may be required in assessing the optimal surgical approach, which balances disease control with quality of life, and probability of noncancer related death.