Colorectal Cancer Flashcards
what are 2 types of colorectal neoplasia?
1) benign
- adenoma
2) malignant
- adenocarcinoma
what are 4 types of colorectal polyps?
- inflammatory
- hamaromatous
- metaplastic
- neoplastic (adenoma)
what are 2 genes associated with cancer?
1) oncogenes
- when normal promotes cell growth and division
- when mutation causes excess cell growth and division
2) tumour supressor genes
- when normal suppress cell growth and division
- when mutated allow cell growth and division
what are the genetics involved in colorectal cancer?
- mutations in APC (adenomatous polyposis coli)
= 100% risk of developing bowel cancer - mutation of p53 gene
= it has a role in repair of DNA - predisposing disease
= long standing IBD
= ulcerative colitis > crohns
= adenomatous polyps
+ APC + K-ras + p53 + 18q loss
describe autosomal dominant inheritance of colorectal cancer?
FAP
= mutation in APC gene
HNPCC
= mutation in DNA mismatch repair gene
what are causes of bowel cancer?
1) environment
2) genetic factors
3) predisposing conditions
- older age
- low intake of fibre
- high intake of fats sugar, red meat, processed meats
- obesity
- smoking
- lack of physical exercise
= exercise = AMPK = glucose uptake by muscle = decreased cell turnover
what are the 3 macroscopic appearances of colorectal cancer?
- polypoidal
- ulcerative
- annular
what are the 2 types of appearances of adenomas?
- tubular
- villous
what are the 3 types of appearances of adenocarcinoma?
- well differentiated
- moderately differentiated
- poorly differentiated
what are ways of spreading
- direct spread
= local via adjacent structures - lymphatic spread
= pericolic nodes
= peri-vascular nodes - blood borne spread
= liver
= lung - trans-coelomic spread (rare)
= peritoneal cavity
how can you pick up colorectal cancer?
1) bowel screening programme
2) urgent - via SOPD or endoscopy
= urgent referral from GP with ‘reg flag symptoms’
3) emergency
- obstruction
= distension
= constipation
= pain
vomiting
- rectal bleeding
- palpable mass
- perforation
how can you stage cancer?
1) dukes’ staging
= A, B, C, D
D - distant mets
2) TNM
T = tumour
N = (lymph) nodes
M = metastases
describe the TNM staging system?
T1 = sub-mucosa
T2 = not muscle
T3 = through muscle
T4 - adjacent structures (including peritoneum)
N0 = no lymph node involvement N1 = < 3 nodes involved N2 = > 3 nodes involved
M0 = no distant mets M1 = distant mets
how does right sided cancers present?
- unexplained iron deficiency anaemia
- persistent tiredness
- persistent and unexplained change in bowel habits
- unexplained weight loss
- abdominal pain (colicky nature)
- lymph in abdomen
how does left sided cancer present?
- rectal bleeding
- feeling of incomplete emptying, tenesmus
- worsening constipation
what are general, abdomen and rectum findings with colorectal cancer?
General
= anaemia
= cachexia
= lymphadenopathy
Abdomen
= mass
= hepatomegaly
= distension
Rectum
= mass
= blood
how would you diagnose primary disease?
- barium enema
- CT colonography
- sigmoidoscopy
- colonoscopy
- Faecal occult blood testing (FOBT)
how would you treat obstruction?
- colostomy alone
- resection + colostomy
- resection + anastomosis
- stenting
what investigations could be used to stage colorectal cancer?
Lungs
= CT
Liver
= CT
Primary rectal cancer
= MRI
what do you do after cancer has been diagnosed?
- histopathology confirmation
- cancer staging
= CT chest/abdo/pelvis
= MRI for rectal cancer - MDT
- surgery/pailiation
- FOU
how do you treat colorectal cancer?
1) surgery
2) radiotherapy
3) chemotherapy
what are examples for surgery of colonic cancer?
- right hemicolectomy
- extended right hemicolectomy
- transverse colectomy
- left hemicolectomy
- sigmoid colectomy
- subtotal colectomy
what are 3 surgeries for rectal cancer?
- abdomino-perineal excision
- anterior resection
- local excision
what are 2 types of radiotherapy for rectal cancer?
1) adjuvant
- pre or post operative
- reduces local recurrence after rectal excision
2) palliative
- inoperable primary rectal cancer
- recurrent rectal cancer
describe the chemotherapy used fo colorectal cancer?
- 5-fluorouracil (5-FU) or capecitabine
- Adjuvant for Stage C
5-10% absolute improvement in survival - For advanced disease
= median survival advantage of ~5 months
= new drugs – oxaliplatin, irinotecan
= Biological agents – cetuximab, bevacizumab
LECTURE 2 - therapy of colorectal cancer
LECTURE 2 - therapy of colorectal cancer
what are 2 ways in which surgery can be carried out?
- open surgery
- laparoscopic surgery
- robotic surgery
post operatively what would you offer?
- chemo/radiotherapy depending on stage
- Follow-up;
= CT
= CEA
= colonoscopy
what are 4 palliation options for colorectal cancer?
- stenting
- palliative radio/chemo
- de-functioning
- bypass
