|Transanal endoscopic microsurgery’s role in residual rectal cancer after neoadjuvant chemoradiotherapy remains unclear|
|Monday, 04 March 2013|
Rodrigo Oliva Perez et al. Transanal endoscopic microsurgery for residual rectal cancer (ypT0-2) following neoadjuvant chemoradiation therapy: Another word of caution in dis colon rectum 2013; 56: 6-13.
In a nutshell
Tumour penetration of the rectal wall (pT0-2) was clinically, endoscopically and radiologically assessed post-treatment.
From January 2009 to October 2011, 190 patients received neoadjuvant chemoradiotherapy for locally advanced rectal cancer. Sixty-three patients had a complete clinical response (excluded from study). Of the 127 with an incomplete response, only 27 patients were favourable for TEM resection (3 pT0, 6 pT1 and 18 pT2 disease). The patients received no systemic adjuvant therapy post TEM.
Local recurrence occurred in 4 patients (15%) after a median follow up period of 15 months. Five patients (19%) had a systemic recurrence (including 2 with local recurrence). No recurrences occurred in the pT0 group, 1:6 recurrence (17%) occurred in the pT1 and 3:18 (17%) in the pT2 group. Post-operative complications were minimal (post-operative haemorrhage necessitating transfusion and anorectal stenosis requiring dilatation under anaesthetic were the two most significant). Tumour size post-chemoradiotherapy (p 0.03) and lymphatic involvement (p 0.049) were the only predictive factors for local recurrence.
The assessment and treatment of rectal cancer is complex, and even in an era where laparoscopic surgery is utilised with increasing frequency, this is an area of controversy. With TEMS, a less invasive/ radical approach, we need to ensure comparable long-term survival and local recurrence rates to the gold standard of TME (c.f. Heald). Local recurrence rates of >15% compared with 5% with radical excision (TME), within short follow-up time following TEMS are not acceptable.
Both techniques of MRI and Intraluminal US may be required for staging rectal lesions to evaluate rectal wall involvement and adjacent regional lymph node morphology. Unfortunately, the categorisation of nodes as being ‘involved’ or ‘reactive’ is also difficult yet pivotal to treatment planning.
In this report, rectal cancer staging, critical for optimal pathway planning, shows poor correlation between radiological and pathological parameters (>25% pathological upgrading over radiological staging). Furthermore, recurrence rates in T1 lesions following TEMS may reflect less ‘radicality’ than TME as supported by the operative description of TEMS resection.
In the era of minimally invasive surgery one must respect basic surgical / oncological principles. Lympho-vascular invasion and encroachment on CRM are a concern (<1mm is an involved CRM). Historical studies of T2 transanal resections had unacceptable local recurrence rates as compared to radical surgery.
Continued development in minimally invasive surgery must be tempered by the danger of drawing too many conclusions from small case studies.