Colorectal cancer Flashcards
Lifetime risk of developing CRC
- Risk is 5-6% 2. Age is the most important risk factor for sporadic CRC
Etiology
- Genetic 2-3 X increased risk when family history in single first degree Further +if occurred at young age
- Environmental Obesity High energy intake ?Red meat
Typical spread
- Lymph nodes
- Liver via venous
- Lung via hematogenously
- Bone
- Brain
Risk factors
- Increasing age
- APC mutation
- Lynch syndrome
- MYH-associated polyposis
- Hamartomatous polyposis
- Inflammatory bowel disease
- Obesity ?Fibre, limited physical activity, acromegaly
Classical Presentations
- Suspicious signs and symptoms
Abdominal pain
Change in bowel habit
Rectal bleeding
Anemia
Abdominal distension
Weight loss
- Asymptomatic with screening
- Emergency w/ obstruction, peritonitis, bleeding
Anemia- more common sign for which side
Right
Investigations
- FBC->anemia
- LFTs->normal unless liver mets
- Renal function, UEC->normal unless compression on ureters
- Colonoscopy->ulcerating exophytic mucosal lesion that may narrow bowel lumen
- Barium enema
- CT thorax, abdomen, pelvis, colonography
Others to consider
- Pelvic MRI
- TRUS
- Biopsy
- CEA
- PET
Monitoring post treatment purposes
- Treatment related complications
- Recurrence at primary
- Metachronous
- Monitor for potentially resectable metastatic
- 3-6 monthly review for 2 years, then yearly for 5 years
Complications of treatment
- bone marrow suppression during chemotherapy
- oxaliplatin-associated hepatotoxicity
- chemotherapy-associated GI (diarrhoea, nausea, vomiting, abdominal pain) 4. chemotherapy-associated alopecia
- cetuximab-associated rash
- radiotherapy-associated faecal incontinence
- bladder dysfunction after rectal excision
- erectile dysfunction after rectal excision
- oxaliplatin-associated pulmonary fibrosis
- oxaliplatin-associated neuropathy
Prognosis
Overall, 5-year survival rates for colorectal cancer are 93% to
- 97% for stage I disease, 90%
- 72% to 85% for stage II disease, 70%
- 44% to 83% (depending on nodal involvement) for stage III disease, 50%
- 10%
Screening guidelines for CRC
- Average risk: FOBT from 50 every 2years
- Moderately increased risk: colonoscopy/sigmoidoscopy 5 yearly from 50, or 10 years younger than age of first diagnosis
- 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
Define average risk
- Aged 50-75
- Asymptomatic
- No personal history
- 1 first degree/2nd w/ CRC >55 yo
Define moderately increased risk
- One 1st degree <55
- Two first or one first + second on same side diagnosed at any age
Define high risk
- Asymptomatic
- 3+ same side with suspected Lynch/other related
- 2 + same side w/ CRC and high risk features
Multiple in same individual
CRC <50
Family member with Lynch
- First degree with large number of adenomas (FAP)
- High risk mutation in APC/MMR
Adenoma recurrent
- 25% after one polyp found
- 50% if multiple adenomas found
Management and F/U for adenomas
- Colonoscopy w/ polypectomy
- >2 polyps/>1cm->yearly colonoscopies
- If clear->3-5 yearly
Types of polyps
- Non-neoplastic
Hyperplastic->most common
Mucosal->no clinical significance
Inflammatory pseudopoylps->IBD, no malignant potential
Submucosal polyps
- Neoplastic
Hamartomas->juvenile, Peutz Jegher: malignant potential due to +adenomas. Most spontaneously regress.
Adenomas->premalignant
Most common location for polyps
Rectosigmoid colon
Degree of malignant potential in adenomas
Villous>tubulovillous>tubular
Pathogenesis of FAP, clinical features, extracolonic features
- AD, mutation at APC
- Hundreds-thousands adenomas by 20
- 100% will develop CRC
- Small bowel Ca, bile duct, pancreas, stomach, thyroid, adrenal. Congenital hypertrophy of retinal pigment.
Variants of FAP
- Gardners: FAP + extra-intestinal lesions: cysts, osetomas, desmoid tumors
- Turcots: FAP + CNS tumors
Treatment in FAP
- Surgery indicated by 17-20
- Total proctolectomy w/ ileostomy or total colectomy w/ ileorectal anastamosis
- Doxorubicin chemoT
- NSAIDs for intra-abdominal desmoids
Pathogenesis of HPNCC, clinical features
- AD, mutation in DNA MMR (SH2/6, MLH1)= microsatellite instability and subsequent mutations
- Early age onset, right >left, synchronous and metachronous lesions
- HNPCC 1= hereditary site specific
- HNPCC 2= cancer family syndromes->high rates of extracolonic tumors (endometrial, ovarian, hepatobiliary, small bowel
Revised bathesda criteria for HNPCC (5)
Tumours from individuals should be tested for MSI in the following situations:
- Colorectal cancer diagnosed in a patient who is less than 50 yr of age.
- Presence of synchronous, metachronous colorectal, or other HNPCC-associated tumours, regardless of age.
- Colorectal cancer with the MSI-H histology diagnosed in a patient who is less than 60 yr of age.
- 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.
- Colorectal cancer diagnosed in two or more first- or second-degree relatives with HNPCC-related tumours, regardless of age.
Diagnosis of HNPCC
- Bathesda criteria
- Genetic testing
- Colonoscopy
- Surveillance for extracolonic lesions
Staging for CRC
Staging for CRC
- I T1,2 N0M0->invasion to muscularis mucosa
- II T3,4 N0M0->invasion into serosa/adjacent structures/organs
- III TxN+M0->Nodal invasion
- IV TxNxM1->distant metastasis
Tumor size
- T0 No primary tumour found
- Tis Carcinoma in situ
- T1 Invasion into submucosa
- T2 Invasion into muscularis propria
- T3 Invasion through muscularis propria and into serosa
- T4 Invasion into adjacent structures or organs
Preoperative management in CRC
- Bowel prep Glytely Picolax on pre-op day
- Antibiotic prophylaxis Metronidazole + cephazolin
- VTE prophylaxis
- Chart regular medications
- Investigations
- Analgesia and antiemetic
Surgical management of cecal/ascending
- Right hemicolectomy- ileocolic vessels divided, Right colic and right of middle colic removed.
Surgical management of Transverse
- If near hepatic flexure-can do right hemicolectomy
- If mid- extended right hemicolectomy w/ anastamosis of terminal ileum and descending colon
- If at splenic- can spread along middle/left colic requires subtotal colectomy anastamosing terminal ileum and sigmoid
Surgical management of descending
- Left hemicolectomy
Inferior mesenteric artery divided at origin and left colic vessels, sigmoid vessels also dissected. Anastamosis between mid-transverse colon and upper rectum
Surgical management of Sigmoid
- High anterior resection anastamosing mid descending colon to upper rectum, Inferior mesenteric artery and left colic vessels with sigmoid braches
Surgical management of perforated
- Hartmanns w. en bloc excision of contained perforation
Proximal end brought out as colostomy and distal end oversewn/ brought out as mucous fistula
Surgical management of obstructing
- Subtotal colectomy w/ ileorectal or ileosigmoid anastamosis
- 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
- Proximal diverting stoma alone w/o resection if proximal colon +dilated, resection hazardous and patient very unwell. Resection in 2 weeks
- Colonic stent->usually in palliative setting, when risk of perforation
Surgical management of rectal cancer
- Anterior resection
- Abdominoperineal resection
- Hartmanns
- Transanal local excision
Anterior resection: indication, anastamosis leak, procedure, prognosis
- Indication
Cancer for upper and mid rectum, small, >2cm margin from the dendate
- Sigmoid colon and rectum removed w/ IMA/LCA dissected. Mesorectum removed.
- Bowel function improves over 12-18 months w/ very distal anastamosis. Internal sphincter impaired->3-6 times/day frequency
Abdominoperineal resection of the rectum: indication, procedure
- T2, T3, poorly differentiated tumors of distal rectum
- Removal of anus, rectum, sigmoid colon + lymph nodes via incision made in abdomen and perineum->end of sigmoid as colostomy
Hartmanns procedure for rectal cancer: procedure
- Anterior resection of rectum w/o anastamosis, generally for palliation or preliminary procedure for acute malignant obstruction or perforation
Transanal local excision
- 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
Treatment of metastasis
- Liver->unless single met, generally incurable
Resection
Hepatic artery embolise or ligation
Chemotherapy
Radiofrequency ablation
- Small bowel resection or bypass
- Pelvis: radiotherapy, chemotherapy
Adjuvant therapy
5-Flurouracil + folinic acid and pelvic radiotherapy
Consenting for colectomy
- 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
- Requires anaesthetic, IV Intubation, Risks
- Surgical risks
Bleeding, infection, damage to other organs Leakage, risk of stoma bag, stricture, adhesions, impotence, bowel obstruction
- 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
- Hospitalisation for 7 days, Off work 1 month
- Any questions
