In colorectal cancer the aims of surgery are:
a. excision of the tumour
b. removal of the lymph nodes that surround the colon and rectum and may
contain cancer cells
c. restoration of the continuity of the lumen of the bowel
In some cases restoration of the continuity of the bowel is not indicated and a
“stoma”, either colostomy or ileostomy is formed.
Bowel preparation is required for all colonic and rectal operations. There are
more than one regimes for that but generally the patient has to stay on a fluid
only diet the day before the operation.
A. SURGERY FOR CANCER OF THE COLON
1. COLECTOMY or HEMICOLECTOMY
Colectomy or hemicolectomy is excision of part of the colon, as well as excision
of the surrounding lymph nodes. Restoration of the remaining colon is achieved
by approximating the ends together using either sutures or staples.
Depending on the part of the colon excised the colectomy is defined as “right
hemicolectomy”, extended right hemicolectomy, transverse colectomy, left
hemicolectomy, sigmoid colectomy, subtotal colectomy or total colectomy.
The colectomy is performed either as a “laparotomy” (by opening the abdomen
with an incision) or “laparoscopically assisted” (by performing most of the
operation through “keyholes”). Laparoscopic surgery is gaining grounds
constantly and is preferred if technically appropriate.
Any colectomy is a major operation. Hospitalisation for 5 to 8 days is usually
required, although it can sometimes be even longer. Details about what to
expect after surgery are contained in another page.
B. SURGERY FOR CANCER OF THE RECTUM
1. ANTERIOR RESECTION OF THE RECTUM
Excision of the rectum is performed by opening the abdomen and entering the
pelvis from the abdominal side (“anteriorly”). It is very important that at the same
time the surgeon performs “Total Mesorectal Excision” or TME. TME means
excision of the “mesorectum” which is a fatty tissue around the rectum
containing lymph nodes. The lymph nodes of the mesorectum are the first site to
be infiltrated by cancer cells which escape the rectum wall. IIt is important that
these lymph nodes are removed so that it is ensured that any cancer cells that
have infiltrated the lymph nodes are removed at the same time.
If TME is not performed correctly at the time of the anterior resection then there
is a high chance of “local recurrence” of the cancer in the pelvis.
Anterior resection of the rectum with TME is a technically demanding operation
which can be performed only by colorectal surgeons and can reduce the risk of
local recurrence.
Although in anterior resection the anal sphincter is preserved, sometimes there
may be a need for a temporary “defunctioning” stoma (either ileostomy or
colostomy). This is in order to prevent consequences from a common
complication, the “anastomotic leak” which is explained elsewhere. If a temporary
defunctioning stoma is required then it can usually be closed (with a smaller
operation) within 3 months.
2. ABDOMINO-PERINEAL (AP) RESECTION OF THE RECTUM
When a rectal tumour lies too low and close to the anal sphincter it is necessary
to remove the anal sphincter at the time of the operation. This is done in order
to eliminate the possibility that cancer cells are left behind.
The removal of the anal sphincter makes it necessary to create a permanent
colostomy.
Total Mesorectal Excision is also performed during an AP resection.
3. LOCAL EXCISION OF RECTAL TUMOUR
When a tumour of the rectum is very early and small in size it is sometimes
possible to have a good curative result without radical surgery. The tumour is
excised with an approach from the inside of the lumen without any abdominal
incision.
This treatment is possible only on early tumours (stage T1) and in most cases it
is necessary to give additionally post-operative radiotherapy.
The decision for local excision of a rectal tumour is more frequently made if the
patient is elderly or with serious concurrent medical problems, in which case
radical surgery carries significant risk.
There are two kinds of local rectal excision:
a) Trans-Anal Resection of tumour (TAR)
b) Transanal Endoscopic Micro-Surgery (TEMS)
TAR is suitable for low tumours of the rectum. TEMS uses specially designed
equipment and it is an endoscopic operation which can be applied for tumours
up to 15 cms from the anal verge.
Both TAR and TEMS are minimally invasive operations and the recovery time is
short. Most patients can go home within 24 -48 hours.
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Surgery for Colorectal Cancer
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