Colorectal cancer Flashcards

1
Q

Lifetime risk of developing CRC

A
  1. Risk is 5-6% 2. Age is the most important risk factor for sporadic CRC
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2
Q

Etiology

A
  1. Genetic 2-3 X increased risk when family history in single first degree Further +if occurred at young age
  2. Environmental Obesity High energy intake ?Red meat
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3
Q

Typical spread

A
  1. Lymph nodes
  2. Liver via venous
  3. Lung via hematogenously
  4. Bone
  5. Brain
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4
Q

Risk factors

A
  1. Increasing age
  2. APC mutation
  3. Lynch syndrome
  4. MYH-associated polyposis
  5. Hamartomatous polyposis
  6. Inflammatory bowel disease
  7. Obesity ?Fibre, limited physical activity, acromegaly
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5
Q

Classical Presentations

A
  1. Suspicious signs and symptoms

Abdominal pain

Change in bowel habit

Rectal bleeding

Anemia

Abdominal distension

Weight loss

  1. Asymptomatic with screening
  2. Emergency w/ obstruction, peritonitis, bleeding
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6
Q

Anemia- more common sign for which side

A

Right

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7
Q

Investigations

A
  1. FBC->anemia
  2. LFTs->normal unless liver mets
  3. Renal function, UEC->normal unless compression on ureters
  4. Colonoscopy->ulcerating exophytic mucosal lesion that may narrow bowel lumen
  5. Barium enema
  6. CT thorax, abdomen, pelvis, colonography

Others to consider

  1. Pelvic MRI
  2. TRUS
  3. Biopsy
  4. CEA
  5. PET
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8
Q

Monitoring post treatment purposes

A
  1. Treatment related complications
  2. Recurrence at primary
  3. Metachronous
  4. Monitor for potentially resectable metastatic
  5. 3-6 monthly review for 2 years, then yearly for 5 years
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9
Q

Complications of treatment

A
  1. bone marrow suppression during chemotherapy
  2. oxaliplatin-associated hepatotoxicity
  3. chemotherapy-associated GI (diarrhoea, nausea, vomiting, abdominal pain) 4. chemotherapy-associated alopecia
  4. cetuximab-associated rash
  5. radiotherapy-associated faecal incontinence
  6. bladder dysfunction after rectal excision
  7. erectile dysfunction after rectal excision
  8. oxaliplatin-associated pulmonary fibrosis
  9. oxaliplatin-associated neuropathy
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10
Q

Prognosis

A

Overall, 5-year survival rates for colorectal cancer are 93% to

  1. 97% for stage I disease, 90%
  2. 72% to 85% for stage II disease, 70%
  3. 44% to 83% (depending on nodal involvement) for stage III disease, 50%
  4. 10%
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11
Q

Screening guidelines for CRC

A
  1. Average risk: FOBT from 50 every 2years
  2. Moderately increased risk: colonoscopy/sigmoidoscopy 5 yearly from 50, or 10 years younger than age of first diagnosis
  3. High risk: refer for genetic screenin a) Lynch->1-2 yearly colonoscopy from 25/5 years younger whichever early. Aspirin 100mg / day b) FAP-> yearly from 12-15 to 30, then 3 yearly
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12
Q

Define average risk

A
  1. Aged 50-75
  2. Asymptomatic
  3. No personal history
  4. 1 first degree/2nd w/ CRC >55 yo
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13
Q

Define moderately increased risk

A
  1. One 1st degree <55
  2. Two first or one first + second on same side diagnosed at any age
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14
Q

Define high risk

A
  1. Asymptomatic
  2. 3+ same side with suspected Lynch/other related
  3. 2 + same side w/ CRC and high risk features

Multiple in same individual

CRC <50

Family member with Lynch

  1. First degree with large number of adenomas (FAP)
  2. High risk mutation in APC/MMR
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15
Q

Adenoma recurrent

A
  1. 25% after one polyp found
  2. 50% if multiple adenomas found
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16
Q

Management and F/U for adenomas

A
  1. Colonoscopy w/ polypectomy
  2. >2 polyps/>1cm->yearly colonoscopies
  3. If clear->3-5 yearly
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17
Q

Types of polyps

A
  1. Non-neoplastic

Hyperplastic->most common

Mucosal->no clinical significance

Inflammatory pseudopoylps->IBD, no malignant potential

Submucosal polyps

  1. Neoplastic

Hamartomas->juvenile, Peutz Jegher: malignant potential due to +adenomas. Most spontaneously regress.

Adenomas->premalignant

18
Q

Most common location for polyps

A

Rectosigmoid colon

19
Q

Degree of malignant potential in adenomas

A

Villous>tubulovillous>tubular

20
Q

Pathogenesis of FAP, clinical features, extracolonic features

A
  1. AD, mutation at APC
  2. Hundreds-thousands adenomas by 20
  3. 100% will develop CRC
  4. Small bowel Ca, bile duct, pancreas, stomach, thyroid, adrenal. Congenital hypertrophy of retinal pigment.
21
Q

Variants of FAP

A
  1. Gardners: FAP + extra-intestinal lesions: cysts, osetomas, desmoid tumors
  2. Turcots: FAP + CNS tumors
22
Q

Treatment in FAP

A
  1. Surgery indicated by 17-20
  2. Total proctolectomy w/ ileostomy or total colectomy w/ ileorectal anastamosis
  3. Doxorubicin chemoT
  4. NSAIDs for intra-abdominal desmoids
23
Q

Pathogenesis of HPNCC, clinical features

A
  1. AD, mutation in DNA MMR (SH2/6, MLH1)= microsatellite instability and subsequent mutations
  2. Early age onset, right >left, synchronous and metachronous lesions
  3. HNPCC 1= hereditary site specific
  4. HNPCC 2= cancer family syndromes->high rates of extracolonic tumors (endometrial, ovarian, hepatobiliary, small bowel
24
Q

Revised bathesda criteria for HNPCC (5)

A

Tumours from individuals should be tested for MSI in the following situations:

  1. Colorectal cancer diagnosed in a patient who is less than 50 yr of age.
  2. Presence of synchronous, metachronous colorectal, or other HNPCC-associated tumours, regardless of age.
  3. Colorectal cancer with the MSI-H histology diagnosed in a patient who is less than 60 yr of age.
  4. Colorectal cancer diagnosed in one or more first-degree relatives with an HNPCC-related tumour, with one of the cancers being diagnosed under age 50 yr.
  5. Colorectal cancer diagnosed in two or more first- or second-degree relatives with HNPCC-related tumours, regardless of age.
25
Q

Diagnosis of HNPCC

A
  1. Bathesda criteria
  2. Genetic testing
  3. Colonoscopy
  4. Surveillance for extracolonic lesions
26
Q

Staging for CRC

A

Staging for CRC

  1. I T1,2 N0M0->invasion to muscularis mucosa
  2. II T3,4 N0M0->invasion into serosa/adjacent structures/organs
  3. III TxN+M0->Nodal invasion
  4. IV TxNxM1->distant metastasis
27
Q

Tumor size

A
  1. T0 No primary tumour found
  2. Tis Carcinoma in situ
  3. T1 Invasion into submucosa
  4. T2 Invasion into muscularis propria
  5. T3 Invasion through muscularis propria and into serosa
  6. T4 Invasion into adjacent structures or organs
28
Q

Preoperative management in CRC

A
  1. Bowel prep Glytely Picolax on pre-op day
  2. Antibiotic prophylaxis Metronidazole + cephazolin
  3. VTE prophylaxis
  4. Chart regular medications
  5. Investigations
  6. Analgesia and antiemetic
29
Q

Surgical management of cecal/ascending

A
  1. Right hemicolectomy- ileocolic vessels divided, Right colic and right of middle colic removed.
30
Q

Surgical management of Transverse

A
  1. If near hepatic flexure-can do right hemicolectomy
  2. If mid- extended right hemicolectomy w/ anastamosis of terminal ileum and descending colon
  3. If at splenic- can spread along middle/left colic requires subtotal colectomy anastamosing terminal ileum and sigmoid
31
Q

Surgical management of descending

A
  1. Left hemicolectomy

Inferior mesenteric artery divided at origin and left colic vessels, sigmoid vessels also dissected. Anastamosis between mid-transverse colon and upper rectum

32
Q

Surgical management of Sigmoid

A
  1. High anterior resection anastamosing mid descending colon to upper rectum, Inferior mesenteric artery and left colic vessels with sigmoid braches
33
Q

Surgical management of perforated

A
  1. Hartmanns w. en bloc excision of contained perforation

Proximal end brought out as colostomy and distal end oversewn/ brought out as mucous fistula

34
Q

Surgical management of obstructing

A
  1. Subtotal colectomy w/ ileorectal or ileosigmoid anastamosis
  2. Hartmann’s->resection of obstruction, prox colon out as left iliac fossa, distal oversewn. Re-anastamose in 4-6 months. Single stage resection w/ intra-op lavage and primary colo-rectal anastamosis
  3. Proximal diverting stoma alone w/o resection if proximal colon +dilated, resection hazardous and patient very unwell. Resection in 2 weeks
  4. Colonic stent->usually in palliative setting, when risk of perforation
35
Q

Surgical management of rectal cancer

A
  1. Anterior resection
  2. Abdominoperineal resection
  3. Hartmanns
  4. Transanal local excision
36
Q

Anterior resection: indication, anastamosis leak, procedure, prognosis

A
  1. Indication

Cancer for upper and mid rectum, small, >2cm margin from the dendate

  1. Sigmoid colon and rectum removed w/ IMA/LCA dissected. Mesorectum removed.
  2. Bowel function improves over 12-18 months w/ very distal anastamosis. Internal sphincter impaired->3-6 times/day frequency
37
Q

Abdominoperineal resection of the rectum: indication, procedure

A
  1. T2, T3, poorly differentiated tumors of distal rectum
  2. Removal of anus, rectum, sigmoid colon + lymph nodes via incision made in abdomen and perineum->end of sigmoid as colostomy
38
Q

Hartmanns procedure for rectal cancer: procedure

A
  1. Anterior resection of rectum w/o anastamosis, generally for palliation or preliminary procedure for acute malignant obstruction or perforation
39
Q

Transanal local excision

A
  1. In early stage rectal too distal for restorative resection, age/infirmity/mets preclude major resection 2. For curative: Mobile tumor in lower third of rectum Tumor
40
Q

Treatment of metastasis

A
  1. Liver->unless single met, generally incurable

Resection

Hepatic artery embolise or ligation

Chemotherapy

Radiofrequency ablation

  1. Small bowel resection or bypass
  2. Pelvis: radiotherapy, chemotherapy
41
Q

Adjuvant therapy

A

5-Flurouracil + folinic acid and pelvic radiotherapy

42
Q

Consenting for colectomy

A
  1. Procedure For excision of cancer

Prep with Golytely, stop taking iron 4 days before/constipating agents.

Will have low residual diet for couple days before.

Day of operation NBM

Site of incision

What will be removed

Use diagram Iliostomy w/ re-anastamosis 6-12 weeks later if required

Prophylactic antibiotics

  1. Requires anaesthetic, IV Intubation, Risks
  2. Surgical risks

Bleeding, infection, damage to other organs Leakage, risk of stoma bag, stricture, adhesions, impotence, bowel obstruction

  1. Recovery Pain->pain relief Infection->antibiotics Hemorrhage w/i 24hrs, 7-14 days possible Possibility of leaking NGT until bowels open Eating and drinking Out of bed day 1-2, mobilise DVT prophylaxis
  2. Hospitalisation for 7 days, Off work 1 month
  3. Any questions