Our Paper of the Month for August aims to summarise and analyse the outcomes associated with completion surgery and undertake a comparative analysis with primary rectal resections.
Completion total mesorectal excision after transanal local excision of early rectal cancer: a systematic review and meta-analysis
Journal: Diseases of the Colon & Rectum Volume 65: 5 (2022)
What is known about this subject?
Rates of transanal excision (TAE) of early rectal cancers are increasing as a means of organ preservation in a select group of patients. Historically, these cT1-2 cN0 tumours were treated by rectal resection with total mesorectal excision (TME). However, TAE may offer benefits in terms of lower morbidity and equivalent oncological safety. Despite this, some tumours resected by TAE may reveal unfavourable, high-risk features or signs incomplete resection which necessitate completion TME surgery. In such cases there have been concerns raised regarding the impact of the inflammation and fibrosis caused by TAE on the quality of the subsequent completion TME. This systematic review and meta-analysis by Wyatt et al. looks to synthesis the evidence relating to completion TME following previous TAE. They also seek to compare primary TME with completion TME in this setting.
Systematic Review and Meta-analysis
Papers reporting the outcomes of patients undergoing completion TME following previous TAE for early rectal cancer. Indications for TAE were individually defined by each author group up to a maximum staging of T2N0. Studies reporting TAE by flexible endoscope, palliative procedures and case reports were excluded
Primary – histopathological specimen quality, long-term survival, and recurrence rates.
Secondary – operative time, abdominoperineal excision of rectum (APER) rate, intraoperative blood loss, postoperative morbidity, conversion to open rates, length of stay, and 30-day mortality rates.
Databases included PubMed, Cochrane library, MEDLINE, and Embase from 1990
to April 2021.
- Twenty-three studies (14 retrospective observational, 9 case-control, no RCTs) including 646 patients were eligible. 8 studies were included in the meta-analyses.
- Most reported transanal endoscopic microsurgery (TEM), some reported TAMIS and some reported resection with a transanal retractor only.
- Weighted average for time between TAE and completion TME was 6.8 weeks
- Completion TME was associated with incomplete mesorectal specimens (risk ratio, 3.06; 95% CI, 1.41–6.62; p = 0.005) but there was no difference in the R1 resection rate.
- Completion TME led to lower lymph node yields (standardized MD, –0.26; 95% CI, –0.47 to 0.06; p = 0.01)
- Rates of APER were higher in the completion TME group but this was not significant (RR, 1.22; 95% CI, 0.97–1.55; p = 0.09)
- Blood loss and operative time were higher in the completion TME group.
- There was no significant difference in rates of intraoperative conversion to open, or in complication rates, or in 30-day mortality between primary and completion TME.
- The weighted average of residual disease in completion TME specimens was 35% for 423 patients
- No difference in local or systemic recurrence was found and there were no significant differences in 3- or 5- year survival between primary and completion TME.
Implications for colorectal practice?
With the increase in TAE for early rectal cancer and the increase in watch and wait programmes colorectal surgeons need to be prepared to undertake completion TME in the event of unfavourable TAE specimen characteristics. This paper provides evidence to suggest that whilst morbidity and survival might be comparable between primary and completion TME we need to be aware of the risk of reduced lymph node yield and incidence of an incomplete TME. The study is limited by the quality of the available literature, particularly the lack of randomised trials. This may reflect the low incidence of completion TME in this setting. Consequently, the conclusions relating to survival and recurrence should be treated with caution. Data relating to stoma rates between groups would also have been noteworthy. Nevertheless, patients should be counselled regarding the risks and benefits of organ preservation in early rectal cancer and should be informed of the outcomes relating to completion TME if this is later required.