Diseases Of The Large Intestine Cancer Of The Rectum Flashcards
(9 cards)
Clinical Anatomy of the rectum
• 12-15 cm from anal verge.
• Diameter
• 4 cm (upper part)
• Dilated (lower part)
Divided into 3 parts
• Upper third
• Middle third
• Lower third
Posterior part of the lesser
pelvis and in front of lower
three pieces of sacrum and
the coccyx
• Begins at the rectosigmoid
junction, at level of third
sacral vertebra
• Ends at the anorectal
junction, 2-3 cm in front of
and a little below the coccy
Blood flow
Arterial supply
• Superior rectal A – fr. IMA; supplies upper and
middle rectum
• Middle rectal A- fr. Internal iliac A. (supplies
lower rectum)
• Inferior rectal A- fr. Internal pudendal A.
Venous drainage
• Superior rectal V- upper & middle third rectum
• Middle rectal V- lower rectum and upper anal
canal
• Inferior rectal vein- lower anal canal
Innervations
• Sympathetic: L1-L3, Hypogastric nerve
• ParaSympathetic: S2
Associated risk factors
Associated risk factors
Male sex
Family history of colorectal cancer
Personal history of colorectal cancer, ovary, endometrial, breast
Excessive BMI
Processed meat intake
Excessive alcohol intake
Low folate consumption
Neoplastic polyps.
Etiological agents
Environmental & dietary factors
Chemical carcinogenesi
Clinical Presentations
• Symptoms
• Asymptomatic
• Change in bowel habit (diarrhoea, constipation, narrow stool,
incomplete evacuation, tenesmus).
• Blood PR.
• Abdominal discomfort (pain, fullness, cramps, bloating, vomiting).
• Weight loss, tiredness.
• Acute Presentations
• Intestinal obstruction.
• Perforation.
• Massive bleeding
Signs
• Pallor
• Abdominal mass
• PR mass
• Jaundice
• Nodular liver
• Ascites
Pathological features
Adenocarcinoma in situ
• Adenocarcinoma
• Mucinous (colloid) adenocarcinoma (>50% mucinous)
• Signet ring cell carcinoma (>50% signet ring cells)
• Squamous cell (epidermoid) carcinoma
• Adenosquamous carcinoma
• Small-cell (oat cell) carcinoma
• Medullary carcinoma
• Undifferentiated Carcinoma
Dukes classification-
Dukes A: Invasion into but not through the bowel wall.
Dukes B: Invasion through the bowel wall but not involving lymph nodes.
Dukes C: Involvement of lymph nodes
Dukes D: Widespread metastases
Modified astler coller classification-
Stage A : Limited to mucosa.
Stage B1 : Extending into muscularis propria but not penetrating through
it; nodes not involved.
Stage B2 : Penetrating through muscularis propria; nodes not involved
Stage C1 : Extending into muscularis propria but not penetrating through
it. Nodes involved
Stage C2 : Penetrating through muscularis propria. Nodes involved
Stage D: Distant metastatic sprea
Prognostic factors
Prognostic factors
Good prognostic factors
Old age
Gender(F>M)
Asymptomatic pts
Polypoidal lesions
Diploid
Poor prognostic
factors
Obstruction
Perforation
Ulcerative lesion
Adjacent structures
involvement
Positive margins
LVSI
Signet cell carcinoma
High CEA
Tethered and fixed
Diagnostic Workup
History—including family history of colorectal cancer or polyps
• Physical examinations including DRE and complete pelvic
examination in women: size, location, ulceration, mobile vs.
tethered vs. fixed, distance from anal verge and sphincter
functions.
• Proctoscopy—including assessment of mobility, minimum
diameter of the lumen, and distance from the anal verge
• Biopsy of the primary tumor
Barium enema
Ct scan
MRI
Treatment
Surgery
• Surgery is the mainstay of treatment of RC
Local excision- reserved for superficially invasive (T1) tumors
with low likelihood of LN metastases
• Should be considered a total biopsy, with further treatment
based on pathology
Low Anterior Resection- for tumors in upper/mid rectum;
allows preservation of anal sphincter
• Abdominoperineal resection
Radiotherapy and chemotherapy
Complications of Surgery
Bleeding
• Infection
• Anastomotic Leakage
• Blood clots
• Anesthetic Risk
