Screening Guidelines for Colorectal Cancer Preoperative Examination
Pretreatment planning requires that patients have a thorough
and detailed preoperative examination (Kwok et al,
2000). Stage of disease and tumor location are the primary
determinants of therapy for rectal cancer but patient variables
often necessitate modification of standard treatment
algorithms.
History
A history of preexisting incontinence or chronic diarrhea
may be contraindications to a colo-anal anastomosis
because such patients will inevitably have poor function
after such an ultralow anastomosis. Patient preferences and
special needs that would make colostomy management
more difficult (blindness, severe arthritis) should be identified
and included in decision-making. Rapid weight loss
or pelvic pain are particularly ominous symptoms and
should intensify the search for metastatic disease.
Digital Exam
Digital rectal examination for low rectal tumors is essential
to define the distal extent, location, mobility, and rela
tionship to the anal sphincter muscles and surrounding
structures. Digital rectal examination also allows a simple
evaluation of sphincter competence, an important factor
in management, particularly of low rectal lesions.
Importantly, the exact location of the tumor must be determined
as small differences in distance from the anal verge
may have a major impact on therapy, particularly the ability
to preserve intestinal continuity.
Rigid Proctoscopy
Rigid proctoscopy more accurately determines the level,
extent, and quadrant(s) involved by the lesion, than does
flexible endoscopy. Rigid proctoscopy also facilitates
obtaining large biopsies of the lesion needed to confirm
the diagnosis of adenocarcinoma (AC) and to identify any
unfavorable histologic features (poorly differentiated,
mucinous, or signet ring histology) that may influence
choice of therapy. Risk of obstruction is a significant concern
and therefore the degree of constriction of the lumen
must be assessed.
Colonoscopy
The entire colon should be visualized by colonoscopy to rule
out synchronous tumors that would influence the planned
resection. If an endoscopist elects to remove a rectal lesion
by polypectomy under the assumption that it is benign,
every effort should be made to remove it in one piece, orient
the specimen before fixation and accurately localize the
lesion site by injection of India ink. These steps are essential
to planning therapy if the subsequent pathology reveals
an unsuspected AC.
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