Download Wide or total mesorectal excision Francis: Seow-Choen

T HE IMPORTANCE OF
W IDE OR
Richard John Heald
Francis Seow-Choen
Surgical Director, Pelican Cancer Centre, Basingstoke, UK
Head & Senior Consultant Surgeon, Department of Colorectal Surgery,
Singapore General Hospital, Singapore
TOTAL MESORECTAL EXCISION
It should be self evident that good cancer surgery must
where a publication in the Lancet by the Swedish Rectal
involve the careful removal of a block of tissue which can
Cancer Group demonstrated that local recurrence rates
be predicted to encompass the whole of the field of spread
had been more than halved and the abdominoperoneal
of a cancer. Physicians might be forgiven for considering
rate had also been more than halved - both these for the
surgeons somewhat lacking in scientific thinking that a
entire population of Stockholm County (1.5 million people).
common cancer such as rectal cancer should have lacked
With the backing of Macmillan Cancer Relief the Pelican
a clear definition of exactly what the optimal tissue block
Centre in Basingstoke is the starting point for a major
should be. Throughout the 20th century the operation of
project of practical workshops and multidisciplinary co-
abdominoperoneal excision was considered to be the gold
operation being developed by surgeons of the Trent region.
standard and it has always been assumed that this was a
It is hoped that, with appropriated historical controls
"thoroughly radical" if perhaps forbiddingly mutilating
already in place, results in Trent may be substantially
procedure. It is now clear that most of the mutilation relates
improved in the same way as been proved in Sweden.
to the removal of tissue which almost never contain
satellites of cancer - the pelvic floor, the anal sphincters,
REFERENCES
the perianal skin and the isciorectal fossa. The reality has
1.
McCall J L, Cox M R, Wattchow D A.
now dawned and is being widely accepted that the field
Analysis of local recurrence rates after surgery alone for rectal
of spread of adenocarcinoma is limited to the mesorectum
cancer.
and that adenocarcinoma is essentially a supralevator
International Journal Colorectal Disease; 10:126-32
compartment disease. Furthermore it is not a disease which
2.
A Lehander Marting, T Holm, L-E Rutqvist, B J Moran, R J Heald,
affects the lateral internal iliac compartments of the pelvis.
B Cedermark Effect of surgical training programme on outcome
In a meta analysis in 1995 an Australian group (McCall
of rectal cancer in the County of Stockholm Lancet; 8 July 2000:93-
et al) of 10,000 patients rather neatly summarised the
96
situation as follows: Where the surgery was unspecified
and described simply as conventional anterior resection
or abdominoperoneal excision the local recurrence rate
was 20.5%, where the clearance of the lateral compartments
had been given priority, as in the Japanese literature, the
local recurrence rate was 12.4%. A comparison where
total mesorectal excision had been defined as the objective
the local recurrence rate in all the publications of that
time was 8.8%. The author has been involved in a series
of teaching workshops in more than 20 countries. These
workshops have been particularly successful in Sweden
P.10
TOTAL MESORECTAL EXCISION
In developed countries colorectal cancer ranks among the
top 2 most frequentlyoccurring cancers. Cure rates are
high if the cancer is picked up early, nonetheless local
recurrence rates vary considerably between centres. Whilst
distal recurrence following curative rectal surgery is a
function of the reliability of staging, local recurrence is
directly correlated with surgical expertise. Hence whereas
some centres report local recurrence after rectal surgery
of 60%, other centres have rates of less than 6%. Thus
Mcfarlane1 , Enker 2 and ourselves report local recurrence
rates of about 6% or less following curative rectal surgery.
Whereas M D Anderson and MGA have rates of up to 60%.
The reason for this wide discrepancy lie in the surgical
approach. Hence conventional rectal surgery uses a hand
behind the rectum to rip the rectum off the prescacral
fascia. This process often tears prescacral veins resulting
in huge blood loss. Anatomic planes are not observed and
cancer containing fascia planes are breached and hence
cancer cells are exfoliated. Recurrence rates are hence
high. The technique of total mesorectal excision however
requires a strict adherence to the development of the plane
outside the fascia propria of the rectum. If the rectum is
totally removed in this plane, the pelvic nerves are
preserved, and cancer cells are contained with the rectal
fascia propria and hence recurrent rates are low. Heald
emphasizes amongst other things, TOTAL mesorectal
excision. Hence there are proponents who remove the
whole mesorectum for all rectal cancers. There are surgeons
now claiming that total mesorectal excision must be
performed even for upper rectal tumours because lymph
nodes below the level of the tumour must be removed in
the TME operation. Such a view indicates a non-thinking
surgeon. No study has shown distal lymphadenopathy
with tumour involvement of more than 4cm in curative
cases. Indeed, many surgeons have emphasized both
adequate mesorectal excision and also preservation of
enough mesorectum to ensure adequate rectal function.
Adequacy of rectal and some remaining mesorectal is
easily preserved in all upper rectal and most mid rectal
tumours. This technique so called wide mesorectal excision
saves distal rectum where possible and hence improves
postoperative anal function. Using this technique, the
Mayo clinic reports local recurrence rates of 7%. Indeed
the difference between TME and WME may not be in the
mesorectum but in the planes of surgery and in the way
tissues are treated with care rather than via the rip and
bleed method of old.
Hence our rule of thumb is TME for all tumours at about
8cm or less from the anal verge because of the ease of
surgery as well as for good oncologic results.
Reanastomosis should be with a colonic pouch for improved
function. For rectal tumours above 8cm a WME should
be performed. This allows a good oncological clearance
and ease of surgery with good anorectal function without
the need for a colonic pouch.
REFERENCES
1 . Mcforlane JK, Ryall RD, Heald RJ.
Mesorectal excision of rectal cancer. Lancet 1993;
341:457-60.
2. Enker WE, Laffer UT, Block GE.
Enhanced survival of patient with colon and rectal
cancer is based upon wide anatomic resection. Ann
Surg 1979; 190:350-8.
3 . Kraemer M, Wiratkapun S, Seow-Choen F, Ho YH, Eu
KW, Nyam D.
Stratifying risk factors for following. A comparison of
recurrent and non-recurrent colorectal cancer. 2001;
44:815-21
P.11