2. Epidemiology Colorectal caner is the third most frequently
diagnosedcancer in the US men and women. 108,070 new cases of colon
cancer and 40,740 new casesof rectal cancer in the US in 2008.
Combined mortality for colorectal cancer 49,960 in 2008. Worldwide
approx. 1 million new cases p.a. arediagnosed, with 529,000 deaths.
Incidence rate in India is quite low about 2 to 8 per100,000 Median
age- 7th decade but can occur any time inadulthood Lifetime risk 1
in 10 for men 1 in 14 for women 3. Incidence in Large Bowel Cecum14
% Ascending colon10 % Transverse colon12 % Descending colon7%
Sigmoid colon25 % Rectosigmoid junct0.9 % Rectum23 % 4. Clinical
Anatomy 12-15 cm from analverge. Diameter 4 cm (upper part) Dilated
(lower part) Posterior part of thelesser pelvis and in front of
lower three pieces of sacrum and the coccyx Begins at
therectosigmoid junction, at level of third sacral vertebra 5.
Clinical Anatomy . Ends at the anorectaljunction, 2-3 cm in front
of and a little below the coccyx Taenia of the sigmoid colonform a
continuous outer longitudinal layer of smooth muscle Fatty omental
appendices arediscontinued 6. Rectum is divided into 3 portions 3
distinct intraluminalcurves ( Valves of Houston)Lower rectum : 3 6
cm fromthe anal vergeMid rectum: 6 cm to 8 -10cmfrom anal verge
Upper rectum: 8 cm to12 -15cm from anal verge 7. Peritoneal
Relations Superior 1/3rd of the rectum Covered by peritoneum onthe
anterior surfacesandlateral Middle 1/3rd of the rectum Covered by
peritoneum onthe anterior surface Inferior 1/3rd of the rectum
Devoid of peritoneum Close proximity to adjacentstructure including
boney pelvis. 8. Arterial Supply Superior rectal A fromIMA;
supplies upper and middle rectum Middle rectal A- fromInternal
iliac A. (supplies lower rectum) Inferior rectal A- fromInternal
pudendal A. 9. Venous Drainage Superior rectal V- upper& middle
third rectumMiddle rectal V- lowerrectum and upper anal
canalInferior rectal vein- loweranal canal 10. Nerve supply
Sympathetic: L1-L3, Hypogastric plexus ParaSympathetic: S2-S4 11.
Lymphatic drainage Upper and middle rectum Pararectallymph nodes,
located directly on the muscle layer of the rectum Inferior
mesenteric lymph nodes, via the nodes along the superior rectal
vessels Lower rectum Sacral group of lymph nodesor Internal iliac
lymph nodesNODAL GROUPSPerirectal Common iliacInternal iliac
Paraortic 12. Lymphatic Drainage 13. Aetiology Etiological agents
Environmental & dietary factors Chemical carcinogenesis.
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. Hereditary Conditions
(FAP, HNPCC) 14. Symptoms Asymptomatic Blood PR(60%) Change in
bowel habit(43%) (diarrhoea, constipation, narrow stool, incomplete
evacuation, tenesmus) Occult bleeding(23%) Abdominal discomfort
(20%)(pain, fullness, cramps, bloating, vomiting) Weight loss,
tiredness Back Pain Urinary symptoms Pelvic pain(5%) indicating
nerve trunk involvement 15. Acute Presentations Intestinal
obstruction Perforation Massive bleeding 16. Signs Pallor Abdominal
mass PR mass Jaundice Nodular liver Ascites Rectal metastasis
travel along portal drainage to liver viasuperior rectal vein as
well as systemic drainage to lung via middle inferior rectal veins.
17. Signs Signs of primary cancer Abdominal tenderness and
distension large bowel obstruction Intra-abdominal massDigital
rectal examination most are in the lowest 12cm & reached by
examining finger Rigid sigmoidoscope Signs of metastasis and
complications Signs of anaemia Hepatomegaly (mets) Monophonic
wheeze Bone pain 18. WHO Classification of Rectal Carcinoma
Adenocarcinoma in situ / severe dysplasia 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 19. 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 nodesDukes D: Widespread
metastases 20. Modified astler coller classification Stage A :
Limited to mucosa Stage B1 : Extending into muscularis
propriapenetrating through it; nodes not involvedbut not Stage B2 :
Penetrating through muscularis propria;nodes not involved Stage C1
: Extending into muscularis propria but notpenetrating through it.
Nodes involved Stage C2 : Penetrating through muscularis
propria.Nodes involved Stage D: Distant metastatic spread 21. TX T0
Tis T1 T2TNM ClassificationPrimary tumor cannot be assessed No
evidence of primary tumor Carcinoma in situ: intraepithelial or
invasion of lamina propria Tumor invades submucosa Tumor invades
muscularis propriaT3Tumor invades through the muscularis propria
into pericolorectal tissuesT4aTumor penetrates to the surface of
the visceral peritoneumT4bTumor directly invades or is adherent to
other organs or structures TisT1T2 T3T4Mucosa Muscularis mucosae
SubmucosaMuscularis propriaSubserosa SerosaExtension to an adjacent
organ 22. TNM Classification 23. Stage grouping Stage 0 I IIA IIBT
Tis T1 T2 T3 T4N N0 N0 N0 N0 N0M M0 M0 M0 M0 M0Dukes A A B BMAC A
B1 B2 B3IIIA IIIB IIIC IVT1-2 T3-4 Any T Any TN1 N1 N2 Any NM0 M0
M0 M1C C C -C1 C2/C3 C1/C2/C3 D 24. Stage 0 Rectal Cancer Known as
cancer in situ, meaning cancer is located in the mucosa. 25. Stage
I Rectal Cancer The cancer has grown through the mucosa and invaded
the muscularis (muscular coat) 26. Stage II Rectal Cancer The
cancer has grownbeyond the muscularis of the colon or rectum but
has not spread to lymph nodes 27. Stage III Rectal Cancer Cancer
has spread to the regional lymph nodes (lymph nodes near the colon
and rectum) 28. Stage IV Rectal Cancer Cancer has spreadoutside of
colon or rectum to other areas of the body 29. Prognostic factors
Good prognosticfactors 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 cancer 30. Stage and Prognosis Stage5-year Survival
(%)0,1Tis,T1;No;Mo> 90I IIT2;No;Mo T3-4;No;Mo80-85
70-75IIIT2;N1-3;Mo70-75IIIT3;N1-3;Mo50-65III IVT4;N1-2;Mo
M125-45
