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130
R. Sethi and S.H. Lee
treatment as this cohort is at higher risk for local recurrent disease. Short-course
neoadjuvant treatment has been shown to reduce local recurrence in operable
disease [ 10, 11 ] .
Those patients with involvement of the CRM (surgical irresectable disease) by
either nodal disease or the primary tumor itself (T3 or T4 disease) are more suitable
for long-course chemoradiotherapy in order to try to downstage disease and make
tumors operable [ 12 ] . Surgery usually follows after an interval of 6–10 weeks, and
this has been shown to reduce local recurrence rates and improve survival.
a
b
Fig. 10.6 ( a ) Bulky rectal
tumor with involvement of
the CRM on the left ( blue
arrows ). This would not be
amenable to curative surgery
and would require
neoadjuvant therapy to
downstage the disease. ( b ) T4
rectal tumor demonstrating
involvement of the CRM on
the right and invasion of the
seminal vesicles ( red arrow ).
The CRM on the left is
preserved ( yellow arrows )
131
10 Imaging in Colorectal Cancer
10.8 MR Restaging of Rectal Cancer Following Neoadjuvant
Chemoradiotherapy
MR restaging in patients who have undergone preoperative neoadjuvant chemo-
radiotherapy can be problematic and is not routinely performed prior to surgery.
There is difficulty in differentiating viable tumor from fibrosis, edema, and
a
b
Fig. 10.7 ( a ) Sagittal, axial, and coronal T2-weighted images demonstrating a T2 rectal tumor
( yellow arrows ) demonstrating an intact muscularis layer with no spread into the mesorectal fascia.
( b ) Sagittal T2W image of a T2 rectal tumor ( white arrow ). Note the intact muscularis ( yellow
arrows )
132
R. Sethi and S.H. Lee
inflammation, as well as a local desmoplastic reaction to the therapy [ 12– 14 ] .
This can result in both overstaging (47%) on MR scanning especially where the
CRM has been involved and understaging (6%) of tumors. Downstaging and
complete tumor response to yp T0–T2 tumors can be more accurately predicted
using a combination of morphological tumor assessment together with volu-
metric analyses [
15 ] which can then be used to individualize treatment
planning.
T downstaging can be seen in up to 55% of patients, N level downstaging up to
80%, and complete tumor response in 14% [ 12– 14 ] .
10.9 Detection and Characterization of Metastases
CT forms the main primary imaging modality in the detection of metastases from
both colon and rectal cancer. However, PET, MRI, and contrast-enhanced ultra-
sound (CEUS) all have roles to play.
10.9.1 MRI
MRI staging of the liver is now an established practice in those patients with meta-
static liver disease being considered for resection. This is due to the ability of
dynamic contrast-enhanced MRI to assess the size, number, and vascular involve-
ment of liver lesions. Use of liver-specifi c contrast agents has further increased the
ability of MRI to characterize lesions. Liver-specifi c contrast agents e.g., Gadoxetix
acid (Primovist – Bayer Healthcare pharmaceuticals), are taken up by hepatocytes
(and Kupffer cells in some cases) on delayed phase sequences and allow a higher
sensitivity and specifi city when compared to both PET-CT and contrast-enhanced
CT (CECT) [ 15, 16 ] (Fig. 10.8 ).
10.9.2 PET-CT
PET works on the principle that tumor cells rely on glucose metabolism and there-
fore concentrate the tracer FDG (fl uorodeoxyglucose). PET-CT has a limited role in
the primary staging of colon cancer but is of use in those with metastatic disease. In
these patients, whole body PET-CT scans can identify radiographically occult extra-
hepatic disease and optimize the selection of appropriate candidates for hepatic
resection [
17, 18 ] .
A recent study presented at the ARRS meeting in 2010 demonstrated a role for
PET-CT in those patients with suspected recurrence [ 19 ] . The study, performed by
133
10 Imaging in Colorectal Cancer
The Christie NHS Foundation Trust examined 71 patients with suspected recur-
rence on CT, MRI, or those patients with an unexplained rising CEA. PET-CT accu-
rately confi rmed recurrent disease in 40/71 patients, demonstrating a defi nite role in
the management of this group of patients (Fig.
10.9 ).
Fig. 10.8 Postcontrast axial
MRI scan of the liver using
Primovist (liver-specifi c
contrast agent). The
background liver has taken
up the contrast revealing two
areas of nonuptake
representing metastases
( green arrows ). Excreted
contrast can be seen in the
bile duct ( blue arrow )
Fig. 10.9 Sagittal section of
a PET-CT scan demonstrating
an area of increased uptake
( green arrows ) just above the
rectal stump ( blue arrow )
involving the sacrum. Biopsy
confi rmed local recurrence
134
R. Sethi and S.H. Lee
With advanced surgical technique and improved chemotherapy, patients with
recurrent disease are being considered for treatment with curative intent. Early
detection is therefore important, and the need for comprehensive follow-up will be
discussed in the next section.
10.10 Contrast-Enhanced Ultrasound
Contrast-enhanced ultrasound (CEUS) involves the use of microbubbles as a con-
trast agent carried in the blood pool, to detect and characterise liver lesions.
Sensitivities have been reported as similar to CT [ 20 ] , but the technique may miss
lesions in deep-sited areas of the liver which are also diffi cult to image with conven-
tional ultrasound. It is therefore primarily used for lesion characterization. It may
also be useful as an adjunct in those patients with a contraindication to MRI where
the CT is equivocal. Other advantages include ease of use (at the bedside), low cost,
lack of ionizing radiation, and the avoidance of nephrotoxic contrast.
10.11 Follow-Up After Curative Treatment
for Colorectal Cancer
There is still controversy regarding the optimal strategy for follow-up after curative
treatment of colorectal cancer. The systematic review by Renehan et al. in 2002 [ 21 ]
analyzed fi ve randomized trials looking at survival benefi ts of intensive follow-up.
They showed that there was evidence for an increased survival after 5 years.
The Greater Manchester and Cheshire Cancer Network guidelines for postresec-
tion intensive follow-up includes 6 monthly CT scans for 2 years followed by annual
CT for 3 years and colonoscopy at 2 years and 5 years. The rationale for intensive
follow-up is based on several papers showing improved survival in patients with
earlier detected metastatic disease [ 22, 23 ] . The UK multicenter FACS (follow-up
after colorectal surgery) trial is looking at intensive follow-up closed in 2009 with
20 centers participating and 4,890 patients recruited and will report when follow-up
is mature.
There are four subgroups within the trial:
1. Group 1 – Symptomatic follow-up only
2. Group 2 – 3 monthly CEA levels for 2 years
3. Group 3 – Intensive CT imaging together with clinical follow-up
4. Group 4 – Intensive CT imaging together with CEA and clinical follow-up, i.e.,
groups 2 and 3 combined
The results of this trial will hopefully answer the question about the value of
intensive follow-up.
135
10 Imaging in Colorectal Cancer
The GILDA Italian trial is also ongoing and is comparing “intensive” follow-up
against minimal follow-up in Dukes B and C colorectal cancer. An interim report
with short follow-up in 2004 did not show any improved survival between the two
surveillance arms [
24 ] .
The BSG Guidelines for follow-up after resection of colorectal cancer suggest
much less intensive follow-up, and the recommendations are CT imaging of the
liver only once within the fi rst 2 years following surgery together with full colonos-
copy after 5 years [ 25 ] .
Several smaller recent studies of intensive follow-up have also shown improved
survival [ 26– 29 ] .
There are huge cost implications for intensive follow-up regimens which need be
taken into account in any such program. The use of risk stratifi cation may be consid-
ered in those patients with the highest risk of recurrence in order to reduce costs [ 28 ] .
10.12 The Role of Colonic Stenting in Acute Large
Bowel Obstruction
The morbidity of emergency surgery for obstructing colorectal cancer is consider-
ably higher (15–30%) than that of elective surgery (5%) [ 30– 32 ] . Over 80% of
colorectal tumors that present as an emergency are obstructed. There is a possible
role for stenting in this group of patients, as a bridge to elective surgery. This allows
patients to be adequately resuscitated, medical comorbidities to be addressed, and
their disease accurately staged prior to defi nitive management. The need for stoma
formation may be reduced. Palliative stenting also has a role in those patients with
advanced disease or medical comorbidities that may preclude surgery.
Stenting, however, is not without risks. Complications include perforation, fail-
ure to stent, and stent migration. The role of endoluminal stenting is still unknown
with little published evidence or randomized trials. The current ongoing CReST
(Colorectal Endoscopic Stenting Trial) aims to randomize patients presenting as
emergencies with acute large bowel obstruction to either stenting as a bridge to
surgery or surgery alone. The trial aims to recruit 400 patients. Primary endpoints
include length of stay in hospital and 30-day mortality [ 33 ] .
Key Points
CT scanning is the principal investigation in staging colon cancer. •
In rectal cancer, MRI is used to stage local disease and CT to assess for •
metastases.
CTC has a high sensitivity and specifi city for both tumors and polyps and •
may have a role in screening. This has also largely superseded double-
contrast barium enemas (DCBE).
136
R. Sethi and S.H. Lee
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S.R. Brown et al. (eds.), Contemporary Coloproctology,
DOI 10.1007/978-0-85729-889-8_11, © Springer-Verlag London Limited 2012
11.1 Introduction
Early cancer can be considered to be malignant disease confi ned to the muscularis
propria of the colon or rectum. The real challenge in early cancer is to differentiate
those patients who truly have early disease from those with a primary tumor con-
fi ned to the bowel wall and metastatic disease. The challenge is signifi cant because
in early cancer, nodal metastatic disease is often microscopic. If we were able to
exclude metastatic disease, treatment decisions would be relatively simple. If the
lesion were excised luminally, by polypectomy, EMR or TEMS, the only consider-
ation post resection would be whether there was an adequate excision margin on
histological examination.
Early cancer is of increasing relevance to the colorectal surgeon. The introduc-
tion in the UK of the Bowel Cancer Screening Programme and greater public aware-
ness and acceptance of invasive investigations are increasing the number of early
stage cancers. Pilots of FOBT indicate that 49% of screen-detected tumors are TNM
Stage I, that is, pT1/2, N0 [ 1 ] . Use of fl exible sigmoidoscopy as the screening tool
may increase this fi gure further [ 2 ] . Advances in magnetic resonance imaging and
endoscopic ultrasound have improved our ability to stage the primary disease, but
identifi cation of metastatic disease, particularly nodal metastatic disease has
improved much less.
J. Hill, M.B.Ch.B., M.Ch., FRCS
Department of Surgery ,
Manchester Royal Infi rmary ,
Oxford Rd. , Manchester ,
M13 9WL , UK
e-mail: james.hill@cmft.nhs.uk
Chapter 11
Early Colorectal Cancer Management
Jim Hill
140
J. Hill
Standard resectional surgery removes the primary tumor and its draining
lymph nodes. This can be curative if there is nodal involvement and is overtreat-
ment if there is not. Local excision of cancer has less signifi cantly less morbid-
ity and mortality than resection. The management of early cancer is therefore a
balance between a reduction in the complications associated with major colon
and rectal resections versus a risk of oncological disaster if the disease is
undertreated.
This chapter will consider staging systems for early cancer, methods of local
excision, pathological assessment of early cancer specimens, and risk assessment
for nodal metastases.
The principles of pathological reporting are the same as for major resections,
but certain features require special attention in local excisions of (presumed)
early cancers with curative intent because they inform the decision for more
radical surgery. The parameters that predict the presence of lymph node metas-
tasis in early tumors are tumor size, poor differentiation, depth of invasion into
the submucosa, and the presence of submucosal lymphovascular invasion
(Box
11.1 ). As the key to subsequent management is histological assessment,
careful pathological handling of the tissues such as pinning out fl at lesions is
essential (Fig. 11.1 ).
Fig. 11.1 Example of a
lesion pinned out on a cork
board to make pathological
assessment easier
Box 11.1: Parameters that Predict the Risk of Lymph Node Metastasis
Tumor size
Poor differentiation
Depth of invasion into the submucosa
Submucosal lymphovascular invasion
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