Bowel cancer Flashcards by Hannah Nolan

Risk factors for colon cancer

Family history in first degree relative
Personal history - colorectal adenomas, colocrectal cancer, ovarian cancer
Hereditary conditions - lynch syndrome, FAP
Personal - Chronic UC or crohns colitis
Excessive alcohol use
Cigarette smoking
Race and ethnicity - african american
Obesity

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What does prognosis of colorectal cancer depend on

Penetration of tumour through bowel wall
Presence or absence of nodal involvement
Presence or absence of distant metastases
Bowel obstruction/perforation = poor prognsosi
Elevated CEA = negative

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Do HNPCC colon cancer patients have a good outlook

Yes

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When is CEA useful in colon cancer

Only in cadidates for resection of liver or lung metastases postoperatively
Stage II/III rectal cacner every 2-3 months for at least 2 years after diagnosis

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Clinical features of colorectal cancer

Rectal bleednig
Change in bowel habits
Abdominal pain
Intestinal obstruction
Change in appetite
Weight loss
Weakness

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What does bright red blood in the toilet suggest about anatomy of where bowel cancer is

Left hand side = bright red blood
Right hand side = dark dried blood - FIT test

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Diagnostic evaluation for rectal cancer

Physical exam and history
PR
Colonsocopy
Biopsy
CEA assay
Immunohistochemistry
MSI testing/DNA mismathc repair

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What might see on physical exam in colorectal cancer

Palpable mass and bright blood in rectum
Adenopathy, hepatomegaly, pulmonary signs if metastatic
Iron deficiency anaemia
Electrolyte, LFT abnormalities

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High risk pathological features colorectal cnacer

Positive surgical margins
Lymphovascular invasion
Perineural invasion
Poorly differentiated histology

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What is the circumferetnial resection margin

Measured in millimeters, CRM is defined as the retroperitoneal or peritoneal adventitial soft-tissue margin closest to the deepest penetration of the tumor.

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Significance of MSI testing in colorectal cancer

5-10% of rectal adenocarcinomas have mismatch repair deficiency
Dont respond well to chemoterhapy
BUT improved survival under 50
Ass w lynch syndrome
Prognosis of II/III rectal cancer

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Who gets colorectal cancer

More common in males 3:1
>70 years peak incidence

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Where are colorectal cancers located?

Rectal - 40%
Sigmoid 30%
Descending colon 5%
Transverse colon 10%
Ascending colon and caecum 15%

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R sided colon cancer presentation

Palpable mass in RIF
Diarrhoea
Weight loss
Anaemia
Occult GI bleeding - non visible but + FIT

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L sided colon cancer presentation

Palpable mass in LIF
CHange in bowel habit - constipation
Tenesmus
Rectal bleeidng
Signs and symtpoms of bowel obstruction
Tend to present earlier

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What is troissiers sign

Enlarged virchows lymph node in L SCF

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FAP specific extracolonic features

Congenital hypertrophy of retinal pigment epithelium - CHPRE
Osteomas of the jaw
Pre-pubertal epidermoid cysts

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Histological types of colon cancer

Adenocarcinomas - majority. Mucinous or signet ring
Scirrhous tumours
Neuroendocrine

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T staging of bowel cancer tumours

T0/is - No evidence of primary tumour
T1 - Tumour invades submucosa - through muscularis mucosa but not propia
T2 - Tumour invades muscularis propia
T3 - Tumour invades through muscularis propia into pericolorectal tissues
T4a - invades visceral peritoneum perforating it
T4B - Tumour directly invades or adheres to adjacent organs or structures

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N stages of colon cancer

N0 - no regional lymph node metastases
N1 - 1-3 peri-colic lymph nodes + or any number tumour deposits present and all identifiable lymph nodes negative
N1 - 1-3 nodes
N2 - 4>
N3 - vascular trunk or apical node mets in any lymph nodes

More complex
N1a - one regional lymph node +
N1b - 2-3 regional +
N1c = no regional lymph nodes + but tumour deposits in subserosa, mesentery or nonperitonealised pericolic/perirectal tissues
N2a = 4-6 regional lymph nodes affected
N2b = 7 or more regional lymph nodes +

What defined if a lymph node is affected in cancer

> 0.2mm

M stages colorectal cancer

M0 = no evidence of metastases by imaging
M1a = metastasis to one site or organ identified without peritoneal
M1b = metastasis to 2 or more sites or organs identified without peritoneal metastasis
M1c - metastasis to peritoneal surface with or without other metastases

What is most important section of staging for prognosis colon cancer

Nodal involvement

Treatment for colorectal cancer

Surgery
Surgery only in stages O+I
Adjuvant chemo from stage II
Metastases - harsher and longer chemo regimes
StageIV and recurrent - systemic therapy, immunotherapy

Surgical treatment for colon cancer

Open surgical resectionn of primary and regional lymph nodes if localised Curative in 25-40% of patients with resectable metastases in liver an dlung

What adjuvant chemotherapy is used in stage II/III colon cancer

5-FU +/- oxaplatin Capecitabine - equivalent alterantive Irinotecan

What test need to do before start patinet on 5FU

DYPD gene testing DPYD2A -> severe life threatening toxicities to fluoropyrimidines eg 5FU

Recurrence of colon cancer stage II risk factors

Inadequate lymph node sampling. T4 disease. Involvement of the visceral peritoneum. A poorly differentiated histology.

what does stage III colon cancer denote

lymph node involvement

Causes of sporadic colon cancer

Series of genetic mutations Allelic loss of APC gene Activation of K-ras oncogene p53 deletion DCC tumour supressor gene deletion

What kind of cancer is often seen caused by HNPCC/lynch syndrome

Proximal colon, poorly differentiated and highly aggressive

What is Garners syndrome

Variation of FAP -> osteomas of skull and mandible, retinal pigemntation, thyroid carcinoma and epidermoid cysts on skin

Treatment for stage III colon cancer

Wide surgical resection and anstomosis Adjuvant chemotherapy Clinical trials

What first line immunotherapy for colon cancer

Pembrolizumab monotherapy

What is often first site of metastases in bowel cancer

liver - from portal vein

what can present similarly to colon cancer perforation

perforated diverticulitis

lifestyle risk factors bowel cancer

red meat alcohol high calorie intake smoking sedentary lifestyle obesity

Where do marjority of colorectal cancers originate from

70% adenocarcinomas from benign adenomatous polyps

Risk factors bowel cancer

Family history of colorectal cancer in a first-degree relative Personal history of colorectal adenomas, colorectal cancer, or ovarian cancer Hereditary conditions, including familial adenomatous polyposis (FAP) and Lynch syndrome (hereditary nonpolyposis colorectal cancer [HNPCC]) Personal history of long-standing chronic ulcerative colitis or Crohn colitis Excessive alcohol use Cigarette smoking Race/ethnicity: African American Obesity

What site of cacner most likely caused by carcinogens from smoke

Bladder

INitial investigations for sus colorectal cancer

Rectal exam FBC Renal and liver function assessmnet Colonoscopy or flexi sigmoidoscopy if cant Double contrast barium enema as alternative CT chest abdo pelvis CEA blood - prognosis

How is long standing pancolitis monitored

Colonoscopy with multiple biopsies

How distinguish liver cysts from bowel cancer mets

MRI

What is best chemo for colon cancer currently accepted as

FOLFOX

Chances of relapse with colon cancer

1 in 3 even if treated with chemo

Options for metastatic treatment of colon cancer

EGFR mAb - cetuximab VEGF - bevacizumab

Genetic mutations ass with colon cancer

BRAFV600 mutant KRAS or NRAS mutant P13K novel treatment PTEN MEK and AKT inhibitors can target KRAS or NRAS mutant tumours

What is the only effective predictive marker to EGFR mAb therapies

KRAS