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Page 4 of 11 Westwood et al. Mini-invasive Surg 2018;2:38 I http://dx.doi.org/10.20517/2574-1225.2018.50

Approximately 25% of patients with rectal cancer undergo APE surgery, although there is considerable
variation in APE rates between hospitals [14,15] . There have been concerns raised that APE surgery is
overused in some centres and it has been proposed that the rate of APE surgery may be used as a surrogate
marker for surgical quality [16,17] . The outcome after APE surgery for low rectal cancer in several studies is
poorer in terms of patient outcome when compared to anterior resections for higher rectal tumours [6,18] . As
previously described, the mesorectum narrows to a waist at the level of puborectalis and commencement
of the sphincters, therefore unlike mid or high rectal tumours, there is less protective tissue between the
tumour and the CRM in low rectal tumours when following the “conventional” TME plane. In addition,
visualisation in a “conventional” APE may be poor in the lithotomy position during perineal dissection
and may lead to surgeons deviating into the wrong tissue plane. These factors are likely to account for the
[6,7]
increased CRM involvement rate in APE surgery and increased risk of intraoperative perforations [19,20] .
In cases of advanced anterior tumours, an en bloc prostatectomy or resection of the posterior vaginal wall
may be carried out due to the negligible perirectal tissue present anteriorly, in order to increase the chances
[6]
of an R0 resection .

Development of more radical techniques for advanced tumours, e.g., extralevator APE has led to improved
clinical outcomes in some studies through a reduction in CRM involvement and perforations compared
to “conventional” APE surgery [7,21,22] . Extralevator APE involves the removal of the levator ani with the
mesorectum and anal sphincters, creating a more cylindrically shaped specimen and thereby providing
[22]
critical extra tissue around a low rectal tumour . Surgical variations in this technique, including use of
the prone jack-knife position, mean that visualisation of the perineal dissection is also improved, helping to
[22]
reduce the risk of straying into the wrong tissue plane . A multicentre European study comparing a large
series of extralevator APE to “conventional” APE found that extralevator APE removed significantly more
tissue around low rectal cancers with a reduction in CRM involvement (50% to 20%, P < 0.001) and reduction
[23]
in intraoperative perforations (28% to 8%, P < 0.001) . Similarly, a 2011 systematic review found a reduction
when comparing extralevator APE to conventional APE in CRM involvement (9.6% vs. 15.4%, P = 0.022),
[24]
bowel perforation (4.1% vs. 10.4%, P = 0.004), and local recurrence rate (6.6% vs. 11.9%, P < 0.001) .

THE ROLE OF PHOTOGRAPHY IN SPECIMEN QUALITY CONTROL
A key component in facilitating feedback on the quality of surgical specimens is keeping a permanent
record of each specimen using digital photography. Digital images should be taken of the anterior and
posterior aspect of the whole intact specimen, preferably prior to inking, opening and fixation, alongside
a metric scale for calibration. Any significant defects in the mesorectal fascia, sphincters or perforations
warrant a close-up image. Similarly, digital images should be routinely taken of the serial cross-sectional
slices taken at 3-5 mm intervals through the tumour to confirm the plane of surgery and demonstrate the
relationship of the tumour to the CRM. In APE, additional close-up images should be taken of the front
and back of the anal canal/sphincter/levator area to record the plane of surgery in this area. Lateral images
may also be helpful. These images should be stored in a departmental archive and should be actively used
in MDT meetings to feed back to surgical colleagues and compare to the radiological appearances. In
addition they can be used for education, research and audit purposes.

PATHOLOGICAL ASSESSMENT OF ANTERIOR RESECTION SPECIMENS
The anatomy of the specimen depends on several factors including the positioning of the tumour,
the quality of surgical dissection, whether a partial or total mesorectal excision has been performed,
whether additional structures have been removed and the individual variation in height of the peritoneal
reflections. The first step is to grade the quality of the mesorectum. The recommended three-point
[25]
grading system for assessment of mesorectal dissection can be seen in Table 1 and macroscopic images
demonstrating these planes of dissection can be found in the Royal College of Pathologists dataset for
[5]
colorectal cancer . Examples of mesorectal and intramesorectal plane surgery can be seen in Figure 2.