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General surgery + HPB - YR3 > Colorectal Cancer > Flashcards

Colorectal Cancer Flashcards

1
Q

Colorectal cancers most common type

A
  • Originate from epithelial cells lining colon
  • Adenocarcinoma most common
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2
Q

How do colorectal cancers develop?

A
  • Progression or normal mucosa to colonic adenoma (colorectal polyps) and then to invasive adenocarcinoma
  • Adenomas can be present for 10yrs or more before becoming malignant - 10% progress to adenocarcinoma
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3
Q

Genetic mutations implicated in pre-disposing to colorectal cancer

A
  • Adenomatous polyposis coli (APC) - APC is a tumour supressor gene which is mutated –> growth of adenomatous tissue eg familial ademomatous polyposis (FAP)
  • Hereditary nonpolyposis colorectal cancer (HNPCC) - DNA mismatch repair gene, defects in DNA repair –> Lynch syndrome
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4
Q

Adenoma carcinoma sequence

A

Normal epithelium –> abnormal epithelium –> small adeoma –> large adenoma –> colonic carcinoma

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5
Q

RF for colorectal cancer

A
  • Sporadic usually - no specific RF
  • Increasing age
  • Male
  • FH
  • IBD
  • Low fibre diet
  • High processed meat intake
  • Smoking
  • Excess alcohol intake
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6
Q

Symptoms of colorectal cancer

A
  • Change in bowel habit
  • Rectal bleeding
  • Weight loss - usually only present if metastasised (unlike upper GI)
  • Abdominal pain
  • Symptoms of iron deficiency anaemia
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7
Q

Right sided vs left sided colon cancer symptoms

A

Right sided:
* Abdominal pain
* Iron deficiency anaemia
* Palpable mass RIF
* Often presents late

Left sided:
* Rectal bleeding
* Change in bowel habit
* Tenesmus
* Palpable mass in LIF or on PR

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8
Q

NICE criteria for 2WW referral for suspected bowel cancer

A
  • 40 years or older with unexplained weight loss and abdominal pain
  • 50 years and older with unexplained rectal bleeding
  • 60 years and older with iron deficiency anaemia or change in bowel habit
  • Positive occult blood screening test
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9
Q

Colorectal cancer screening

A
  • Faecal immunochemistry test
  • Every 2 years to men and women aged 60-75
  • Uses antibodies against human Hb to detect blood in faeces
  • If +ve - appointment with specialist nurse and colonoscopy
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10
Q

Bedside and bloods for ?colorectal cancer

A
  • FBC - microcytic anaemia?
  • LFTs
  • Clotting
  • Carcinoembryonic antigen (CEA) tumour marker - monitor disease progression pre and post treatment but NOT to diagnose (poor specificity and sensitivity)

Elevated baseline CEA = worse prognosis

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11
Q

Imaging for colorectal cancer

A
  • Colonoscopy + biopsy = gold standard
  • If unsuitable eg frailty, co-morbids CT colonography can be done
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12
Q

Once diagnosis made, other investigations for staging colorectal cancer

A
  • CT scan - chest abdomen and pelvis - look for mets and local invasion
  • MRI rectum - for rectal cancers only, assess depth of invasion and need for pre-op chemo
  • Endo-anal USS - early rectal cancer T1 or T2, check for trans-anal resection suitability
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13
Q

What happens to biopsy samples?

A
  • TNM
  • Histological subtyping
  • Grading
  • Assess for lymphatic, perineural (nerve invasion) and venous invasion
  • Tumour markers also assessed - identify Lynch syndrome and optimise chemo regimes
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14
Q

Additional staging for colorectal cancer (other than TNM)

A
  • Dukes - not used as often now
  • A-D
  • A is confined to muscularis propria
  • B - extends through MP
  • C - involved regional lymph nodes
  • D - distant mets
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15
Q

General management colorectal cancer

A
  • Discuss MDT
  • ONLY curative option is surgery
  • Chemotherapy and radiotherapy have important role as adjuvant and neoadjuvant therapy and palliation
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16
Q

Surgical plan in general for colorectal cancer

A
  • Regional colectomy usually with good margins and removal of lymphatic drainage
  • Then either primary anastomosis or formation of stoma
17
Q

Typical surgeries for colorectal cancer

A
  • Right hemicolectomy or extended right hemicolectomy
  • Left hemicolectomy
  • Sigmoidcolectomy
  • Anterior resection
  • Abdominoperineal resection
  • Hartmanns
18
Q

Right hemicolectomy or extended right hemicolectomy

A
  • For caecal tumours or ascending colon tumours
  • Extended option if involving transverse colon
  • Ileocolic, right colic and middle colic vessels divided and removed with mesenteries
19
Q

Left hemicolectomy

A
  • For descending colon tumours
  • Left branch of middle colic vessels, inferior mesenteric vein and left colic vessels divided and removed with mesenteries
20
Q

Sigmoidcolectomy

A
  • For sigmoid colon tumours
  • IMA fully dissected out with the tumout to ensure adequate margins
21
Q

Anterior resection

A
  • For high rectal tumours - typically if >5cm from anus
  • Remove rectum and sigmoid colon
  • Leaves rectal sphincter intact if anastomosis performed
  • Defunctioning loop ileostomy done to protect anastomsis and reduce risk of leak - reverse in 4-6 months
22
Q

Abdominoperineal resection

A
  • For low rectal tumours - within 5cm of anus
  • Excise distal colon, rectum and anal sphincters
  • = permanent colostomy
23
Q

Hartmanns procedure

A
  • Emergency bowel surgery
  • Eg bowel obstruction or perforation
  • Complete resection of recto-sigmoid colon with formation of end colostomy and closure of rectal stump
24
Q

How can colorectal cancer presenting as bowel obstruction be managed?

A
  • Decompressing colostomy OR endoscopic stenting
  • Then staging and patient status can be optimised
25
Q

When is chemotherapy used for colorectal cancer?

A
  • Advanced disease
  • Metastatic
  • Is tailored with patient specific and disease specific predictive markers
26
Q

Examples of chemotherapy regime for colorectal cancer

A
  • FOLFOX
  • Folinic acid
  • Fluourouracil
  • Oxaliplatin

Also newer biologic agents and immunotherapy

27
Q

When is radiotherapy used?

A
  • Rectal cancer - rarely given in colon due to risk of damaging small bowel
  • Neo-adjuvant and can be alongside chemotherapy
  • Useful if threatened circumferential resection - if cancer will be within 1mm of resected margins
  • So have pre-op long course chemoradiotherapy to shrink so increase chance of complete resection and cure
  • Then surgery 8-10 weeks after
28
Q

What can sometimes happen to rectal cancer with chemo-radiotherapy?

A
  • Complete response
  • Rectal preserving approach sometimes and watch and wait with close surveillance
29
Q

Palliative care for colorectal cancer

A
  • Very advanced
  • Focus on reducing cancer growth and ensuring symptom control
30
Q
A

General surgery + HPB - YR3 (38 decks)

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