Pathology and Evaluation of Colorectal cancers : Pathology and Evaluation of Colorectal cancers Dr.Musharraf Husain
MS, MNAMS, MRCSEd, FACRSI
Colorectal cancers : Colorectal cancers Most Common malignancy of GI tract
Third most common site of new cancer
The risk for developing invasive colorectal cancer increases with age
The overall incidence of colorectal cancer decreasing
Distribution of Colorectal CA : Distribution of Colorectal CA
Classification : Classification
CLASSIFICATION : CLASSIFICATION
CLASSIFICATION : CLASSIFICATION
CLASSIFICATION : CLASSIFICATION
Familial Adenomatous Polyposis : Familial Adenomatous Polyposis Autosomal dominant
>100 polyps
Extracolonic manifestations
Mutation in APC gene (5q21)
Atteneuated FAP
Hereditary NonpolyposisColorectal Cancer (HNPCC) : Hereditary NonpolyposisColorectal Cancer (HNPCC) Lynch I and II syndrome
3-5% of all colorectal cancers
Microsatellite instability (85-90%)
Early onset, Right sided involvement
Diagnosis-
Amesterdam Criteria
MSI Testing
Amesterdam Criteria II : Amesterdam Criteria II Three relatives with HNPCC cancers
Two successive generation
One should be < 50yrs
FAP should be excluded
Verified by a good Pathologist
Risk Factors (Extrinsic) : Risk Factors (Extrinsic) Dietary Fiber, Meat, and Fat
Calcium, Vitamins, and Micronutrients
Aspirin and COX-2 Inhibitors
Cholecystectomy and Bile Acids
Smoking and Alcohol Consumption
Intrinsic Risk Factors : Intrinsic Risk Factors Personal and Family History
Inflammatory Bowel Disease
Colon Cancer: A Genetic Disease : Colon Cancer: A Genetic Disease Two types of genetic instability
The chromosome level - Chromosomal instability, LOH
At the DNA level -Microsatellite instability (MSI),
Adenoma-Carcinoma Model : Adenoma-Carcinoma Model
Morphological Classification : Morphological Classification Annular
Polypoidal
Ulcerative
WHO Histopathologic Classification : WHO Histopathologic Classification Adenocarcinoma
Mucinous adenocarcinoma
Signet ring cell carcinoma
Small cell carcinoma
Small cell adenosquamous carcinoma
Squamous cell carcinoma
Undifferentiated carcinoma
Staging of Colon Cancer : Staging of Colon Cancer
TNM Staging of Colon Cancer : TNM Staging of Colon Cancer Primary Tumor (T)
Tis Carcinoma in situ
T1 Tumor invades submucosa
T2 Tumor invades muscularis propria
T3 Tumor invades through muscularis propria into the subserosa or into nonperitonealized pericolic or perirectal tissues
T4 Tumor perforates visceral peritoneum or directly invades other organs or structures
TNM Staging of Colon Cancer : TNM Staging of Colon Cancer Regional lymph nodes (N)
N0 No regional lymph node metastases
N1 Metastasis in one to three regional lymph nodes
N2 Metastasis in four or more regional lymph nodes
TNM Staging of Colon Cancer : TNM Staging of Colon Cancer Distant metastasis (M)
M0 No distant metastasis
M1 Distant metstasis
Clinical Presentation : Clinical Presentation Change in Bowel habits
Bleeding P/R
Pain abdomen
Pelvic or Anal pain
Weakness, loss of appetite Weight Loss
Anemia
Mass abdomen
DRE
Obstruction
Perforation
Investigations : Investigations Goals
To assess the large bowel
Primary lesion
Concomitant lesion
Other underlying disease
To detect metastasis (staging)
To assess the patients operability
To assess the large bowel : To assess the large bowel Endoscopy
Contrast enema
Virtual Colonoscopy
Endorectal USG
Endoscopy : Endoscopy Rigid Sigmoidoscopy
Flexible Sigmoidoscopy
Colonoscopy
Colonoscopy : Colonoscopy Gold Standard
Diagnostic / Palliative
Synchronus / Metachronus lesion
Limitations
Contrast Enema : Contrast Enema Cost Effective/ Availability
Accurately visualizing the position of lesion
Obstructing Lesion
Disadvantages
Virtual Colonoscopy : Virtual Colonoscopy Generate 3-D images of Colon
Good bowel preparation is required
Endorectal Ultrasound : Endorectal Ultrasound
To detect metastasis (staging) : To detect metastasis (staging) Chest X-ray
Ultra sonogram
CT Scan
MRI
Tumor Marker and Genetic Testing : Tumor Marker and Genetic Testing CEA
Mainly a prognostic marker
Genetic Defects
APC, DCC ,p53.
K-ras gene
hMLH1, hPMS1, hMSH6
Screening Recommendations : Screening Recommendations FOBT Annually
Sigmoidoscopy- 5yearly
FOBT annually & Sigmoidoscopy 5 yearly
Contrast Study- 10years
Colonoscopy- 10years
Slide 32 : Thank you