Colon Cancer Flashcards
what are the risk factors for colon cancer?
age male sex previous adenoma (CRC) diet (low fibre, fruit and veg, Ca & high red meat and alcohol) obesity lack of exercise diabetes mellitus HNCC FAP CRC syndromes IBD
what is the presentation of colorectal cancer?
rectal bleeding (mixed in with stool) loose stool >4wks iron deficiency in men non-mestration in women palpable rectal mass or right lower abdominal mass acute colonic obstruction weight loss anorexia
what are the investigations used to diagnose colon cancer?
colonoscopy
barium enema
CT colonography
CT abdomen/pelvis
what are the main treatments for colon cancer?
surgery
chemotherapy
radiotherapy
when is radiotherapy given?
only in rectal cancer
how is colon cancer staged?
TNM
dukes
describe how dukes staging criteria works.
A - only invasion of submucosa
B - invasion through muscularis but not lymph node involvement
C - lymph node involvement
D - metastasis
what treatment would someone with dukes A stage colon cancer or someone with cancer polyps have?
endoscopic or local resection
in what type of cancer is radiotherapy only used for?
rectal cancer
what therapy is used neoadjuvant?
radiotherapy
may also be with chemo
what therapy is adjuvant?
chemotherapy
what treatment is given if there is positive lymph node involvement?
chemotherapy
+/- surgery
name a chemotherapy drug.
5-FU (fluorouracil)
what palliative care is given to someone with colon cancer?
chemotherapy and/or colonic stenting
what is the prognosis of someone with Dukes stage A,B,C and D at 5 yrs?
A = 83% B = 64% C = 38% D = 3%
What is the most effective screening method for colorectal cancers?
faecal immunological test (FIT)
what ways can we screen for colonic cancers?
faecal occult blood test faecal immunochemical test flexible sigmoidoscopy colonoscopy CT colonoscopy
at what age does someone qualify for the Scottish bowel screening programme?
age 50-74yrs
why is the FIT test more reliable than the FOB test?
FIT is more accurate as it is specific for human haemoglobin
it is both automated and quantitative
reduced interval cancer rate
what ‘high risk groups’ are screened for colorectal cancers?
FAP HNCC inflammatory bowel disease previous adenomas/CRC family history of CRC
what type of mutation causes FAP?
mutation of the APC gene on chromosome 5
is FAP dominant or recessive?
autosomal dominant
when are people with FAP screened for colon cancer?
screened from 10-12 yrs annually
what treatment can be given to people with FAP?
prophylactic protocolectomy
NSAIDS chemoprevention
what role does NSAIDS have on the treatment of FAP?
reduces the no. if polyps and prevents recurrence of higher grade adenomas in the retained rectal segment
what are the complications of FAP?
Extra colonic manifestations i.e. Gastric, cystic, funds, hyperplastic polyps & Periampullary cancer- 90% chance of developing duodenal adenomas
Desmoid tumours
CHRPE - congenital retinal hypertrophy of the pigment epithelium
is HNPCC dominant or recessive?
autosomal dominant
what is the mutation in HNPCC?
DNA mismatch repair (MRR) genes
i.e. MLH1 & MSH2
what is the characteristic is HNPCC tumours?
micro satellite instability (MSI)
frequent mutations in short repeated DNA sequences
when does screening in people with HNPCC begin ?
25 yrs old - every 2 yrs
what side is HNPCC found in the colon?
right side
what are associated cancers of HNPCC?
endometrial
genitourinary
stomach
pancreas
how is HNPCC diagnosed?
genetic testing clinical criteria (amsterdam / bethesda)
