Are We Ready for Extralevatory Abdominoperineal Excision?
Klein et al1 reported an interesting nationwide investigation focusing on extralevatory abdominoperineal excision (ELAPE) efficacy, based on Danish Colorectal Cancer Group's prospective database from 2009 to 2012. The authors concluded that, when compared with conventional abdominoperineal excision (APE), rectal tumor resection after ELAPE had a higher rate of positive circumferential resection margin [CRM(+)] and comparable rate of intraoperative perforation (IOP). However, we would like to comment on the effectiveness of ELAPE and routine practice of this procedure.
APE is the standard treatment of rectal cancer when there is evidence of anal sphincter invasion. However, this traditional technique may be concurrent with higher CRM(+) and IOP rates than anterior resection using total mesorectal excision principle, leading to poorer long-term local control. This may be associated with an anatomical reduction in the natural mesorectal tissue volume in the distal rectum when following the mesorectal plane.2 Thus, ELAPE is introduced to improve the oncological outcomes of low advanced cancer of the rectum and the anus.
Among the published, institution-based control studies with relatively large volume, some literatures indicated decreased CRM(+) and IOP rates3,4 whereas others showed comparable pathological outcomes.5,6 Besides the Danish data mentioned earlier, Ortiz et al7 reported the Spanish nationwide propensity score matching study, which indicated that ELAPE was not more effective than APE in improving CRM involvement ratio. Only one small randomized control study was available and supported the superiority of ELAPE.8 Pooled analysis of all current evidences is not practical because of significant heterogeneities between studies. [In our preliminary test of CRM(+), P value of heterogeneity = 0.007, I2 = 86%.]
We support the issue that ELAPE should only be performed by experienced colorectal specialists instead of any surgical caregivers in a certified large-volume hospital. The latest quantitative systematic review of those institution-based studies concluded that ELAPE still had more advantages than conventional APE, according to the pooled OR (odds ratio) of oncological outcomes [CRM(+): OR = 0.36, 95% CI (confidence interval) = 0.23–0.58; IOP: OR = 0.31, 95% CI = 0.12–0.80; both compared with APE, no statistical heterogeneity between groups in each comparison].9 The background, like specially trained colorectal surgeons and high-volume hospitals, may be the potential reason of explanation.
Another issue of ELAPE is filtering appropriate candidates instead of any patients with low rectal cancer. The Danish data showed that significantly more patients with locally advanced tumors received ELAPE than APE, which indicates potential selection bias by surgeons, leading to the higher CRM(+) risk in the former group.1 Clinical and pathological T0–2 patients were enrolled in several studies without preoperative restaging1,3,4,7 while the necessity of ELAPE for them was quite doubtable. Even if it has to be accepted that current imaging tools are neither sensitive nor specific enough for rectal cancer restaging after concurrent neoadjuvant chemo- and radiation therapy, it is better than nothing, especially considering a higher morbidity rate and a longer hospital stay after ELAPE.
In summary, we conclude that ELAPE may still be effective in highly selective situations. We think the Danish investigation will not be the prohibition sign of ELPAE in routine colorectal surgical practice but a great milestone of conducting future studies to develop the guidelines for such an aggressive powerful procedure.