Colorectal Cancer Flashcards
Colorectal cancer is a/an ______genous disease classified into different subtypes that have specific morphological and molecular characteristics
Studies have shown _____asing incidence with _______ prognosis
hetero
incre; dismal
Colorectal cancer is the _____ most common cancer accounting for ____% of all cancers and _____ most common
cause of (9.4%) of all cancer deaths. Globocan, 2020
4th; 10
2nd
Increasing Incidence of CRC
• It’s projected that global incidence will increase by ___% in 2035 with significant rise in the _______ and ______ countries
80
young and underdeveloped
Increasing Incidence of CRC
• Review of CRC in Nigeria have also indicated ______asing incidence in with greater proportion in (younger or older?) patients
incre
Younger
Age and Gender Prevalence
• The mean ages in most studies in
Nigeria ranged from _____ to ______ years
(average of _____years).
39 to 50.7
46.2
Age and Gender Prevalence
• M:F ratio = ——- to _____
• Patients <40years =______ %
1.3 to 1.
32.2
Aetiology/Predisposing factors
• CRC is a/an _____genous and _____-factorial disease
hetero
multi
Aetiology/Predisposing factors of CRC
• Multiple factors predispose to the disease:
•________ and ______
• host __________ disorders
•__________
Environmental & dietary
inflammatory GI
Genetic
Predisposing factors to CRC
Environmental and Dietary factors
• High content of ______ and ______
• Low content of _______________ in
diet
• Low overall __________ and ______ intake
• Low intake _____ micronutrients
• _______ and ______ consumption
• Obesity
•_______ habits
red meat and animal fat
un-absorbable fiber
fruits and vegetable
protective
Alcohol and tobacco
Sedentary
Protective factors against CRC
• Use of ______ (_____ ————)
• Vegetables
•______ activity
• _____________________ therapy
•_______ intake
NSAIDs; COX 2 inhibitors
Physical
Hormone replacement
calcium
Host inflammatory disorders that predispose to CRC
Inflammatory bowel diseases such as
•________________
•_______ disease
• The risk increases with ______ of the IBD and the ________ of ____________
Ulcerative colitis
Crohn’s; duration
extent of colonic involvement
Risk factors- Genetic (Major Familial
syndromes)
2 conditions
Mention them
Hereditary non-polyposis coli (HNPCC) syndrome
Familial adenomatous polyposis (FAP) syndrome
Risk factors- Genetic
Hereditary non-polyposis coli (HNPCC) syndrome
Abnormal Genes:
Lifetime cancer risks:
Features:
DNA mismatch repair gene MLH1, MLSH2, MSH6, PMS2
50-80%
No polyps, microsatellite instability
Risk factors- Genetic
Familial adenomatous polyposis (FAP) syndrome
Abnormal Genes:
Lifetime cancer risks:
Features:
APC gene mutation in on chromosome 5q21.
100% by age , 40yrs
multiple adenomatous polyps throughout the GIT (50-500 polyps)
Classification of CRC Pathology
• CRC is a single disease
T/F
F
• CRC is not a single disease but a collection of multiple diseases
Classification of CRC Pathology
• It is highly ______genous and dynamic with multiple ______ and ______ alterations underlying its
pathogenesis.
hetero
genetic and epigenetic
Classification of CRC Pathology
• The different subtypes have distinct clinical, morphological, and molecular characteristics which explains the differences in disease outcomes and
response to therapy
T/F
T
Classification of CRC : Hereditary or acquired
Hereditary-____-___%
•____ syndrome
•____________ syndrome
• others
Sporadic -____-____%
• Complication of ________________
20-30 ; Lynch; Familial Polyposis
70-80; Inflammatory bowel syndrome
Classification of CRC: Anatomic
based on location of the tumour
___________ and _________ colon cancer
Right sided
Left sided
Classification of CRC: Molecular
based on the _________________
underlying genetic abnormality
Molecular classification
• In CRC, the transformation of colonic mucosa into invasive cancer occurs through __________ or __________ changes
within the genome and epigenome
• -so-called _______ and ________ hypothesis
an accumulated somatic or inherited
multi-hit and multi-step
Tumour Cancer Genome Atlas, TCGA,
____________(___%)
____________(___%)
____________(___%)
Hyper mutated; 13
Ultramutated; 3
Chromosomal instability;84
Consensus Molecular Subtype
___________(_____%)
___________(_____%)
___________(_____%)
___________(_____%)
___________(_____%)
MSI: immune; 14
Canonical; 37
Metabolic ;13
Mesenchymal ;23
Mixed features;13
Tumour Cancer Genome Atlas, TCGA : Consensus Molecular Subtype
__________ = _________
__________ = ___________
Hypermutated; CMS1 : MSI immune
Chromosomal instability; canonical, metabolic, and mesenchymal
Anatomical location of:
MSI immune
Canonical
Metabolic
Mesenchymal
Right sided colon
Left sided colon and rectum
No predominance
Typically diagnosed at more advanced stages
Prognosis and survival of:
MSI immune
Canonical
Metabolic
Mesenchymal
Good prognosis but poor survival after relapse
Good survival after relapse
Intermediate survival
Worst overall and relapse-free survival
Treatment plan for :
MSI immune
Canonical
Metabolic
Mesenchymal
Likely benefit from immune checkpoint blockade
Anti-EGFR therapies likely effective , may respond to oxali-platin based regimens
Likely resistant to anti-EGFR therapies
Maybe responsive to antiangiogenic therapies and perhaps more sensitive to irinotecan-based regimens
Colorectal carcinogenesis
• The mechanisms that underlie
development of CRC have been
described as a “multi-hit, multi-stage”
phenomenon in which
•__________ mutations (alterations or changes) occur in ______ genes, after exposure to ___________ of
environmental and dietary risk factors.
several
multiple
multiple hits
Colorectal carcinogenesis
These mutations occur at (same or different?) stages and result in increasing _______________ from normal _____proliferative epithelium,
to _________,__________ and then finally _________
As the tumour grows, it is prone to _________ that confer on it, _________________ potential
Different
phenotypic abnormality; hyper
small adenoma, large adenoma
invasive cancer; more mutations
metastatic potential
3 Major Pathogenetic Pathways in CRC
Pathology
___________
_______________
______________
Chromosomal instability
Hypermutated (microsatellite instability)
Serrated pathways
Chromosomal instability
Hypermutated (microsatellite instability)
Serrated pathways
Sporadic:
Hereditary:
80%; FAP 1%
15%; Lynch syndrome 3-4%
10-20%
Chromosomal instability
_______ activation
__________ inactivation
(Early or Late?) abnormalities of _____ pathway
Oncogen
Tumor surpressor gene
Early abnormalities of WNT
Hypermutated (microsatellite instability)
Defective ___________________
DNA mismatch repair
Serrated pathways
Overlapping with ________________
Mutation in _______ or _______ leading to ________ of ______ pathway
CIN and MSI
KRAS or BRAF
hyper activation of
MAPkinase
Chromosomal instability
_____________________ sequence
•________ ————
Adenoma→Carcinoma
Classical adenocarcinoma
Hypermutated (microsatellite instability)
_______ differentiated tumour
•_____________ lymphocytes
Poorly
Tumour infiltrating
Serrated pathways
Premalignant lesions-
• Traditional _________ (TSA) and
•_____________ adenomas/______
serrated adenomas
Sessile serrated
polyps
The adenoma-carcinoma mode of
mechanism of pathogenesis
• This implies that ———————————————————————-
some carcinoma of the colon arise
from adenoma
The adenoma-carcinoma mode of
mechanism of pathogenesis
There is cumulative alteration in the genome which results in→ increasing _____,______ of _______ & ______ potential
of the tumour→carcinoma
size, level of dysplasia
invasive
Microsatellite instability pathway
• characterized by genetic abnormalities in the _________________ genes
• It is responsible for ____-____% of sporadic colorectal cancers
DNA mismatch repair
10-15
_____________ is the main pathway in Hereditary non-polyposis coli cancer syndrome (HNPCC syndrome).
Microsatellite instability pathway
Microsatellite instability pathway
Cancer occurs in ______ colon, tends to be _________ and in (younger or older?) age.
• There is Increase incidence of ______ and ________ cancer
proximal; mucinous
Younger
endometrial and ovarian