Colorectal cancer Flashcards
presentation of colon cancer
varies.... can be: asymptomatic weakness/anemia change in bowel habits (classic) bloody stool
what are the two types of polyps found in the colon and rectum
ademonas
hyperplastic polyps
what type of polyp usually causes cancer
pre existing adenomas
hyperplastic polyps have no malignant potential
which adenomas have greatest malignant potential
“advanced” adenomas…
tubular adenomas more than 1 cm
villous adenomas
adenomas with high grade dysplasia
sessile serrated polyps more than 1 cm
sessile serrated polyps with dysplasia
traditional serrated adenoma
how long does it take for a small adenoma to develop into malignancy
5-10 years
therefore cancer may be prevented by adenoma removal
what are average risk patients for colon cancer screening
meet none of criteria for increased risk
50-74 years old, or over 74
what are the increased risk patients for colon cancer screening
personal hx of adenomas (particularly advanced or multiple)
1st degree relative age less than 60 with CRC or advanced or multiple adenomas
two or more 1st degree relatives with CRC at any age
longstanding IBD
family hx of familial FAP or HNPCC
screening for average risk asymptomatic patients aged 50-74
FIT test every 1-2 years
any positive FIT followed by colonoscopy–> can reduce mortality from CRC
colonoscopy every 10 years is also acceptable screening
screening for average risk patients over 74 years old
individually assess screening to balance risk and benefit
*not recommended after age 85
screening for patients with 1st degree relative younger than 60 with CRC or advanced adenomas (or two or more 1st degree relatives with CRC at any age)
colonoscopy every 5 years starting at age 40 or 10 years earlier than the age of youngest affected relative at dx
use FOBT, FS and CT colonography only when patients decline colonoscopy or have incomplete colonoscopy
screening for patients with IBD involving majority of colon for over 8 years or left colon for over 15 years
colonoscopy every 1-2 years with multiple biopsies to detect occult neoplasia
what is FAP
rare autosomal dominant syndrome
germline mutations in adenomatous polyposis coli (APC) gene
presence of 100 or more adenomatous colorectal polyps (can be up to thousands carpeting the mucosa)
polyposis typically develops in the second or third decade of life
colorectal cancer occurs in 100% of untreated individuals by age 45 years
FAP screening
geneting counseling and testing should be offered to all 1st degree relatives as soon as possible through the hereditary cancer program at BCCA
people with FAP and their first degree relatives should be followed by GI who will work with BCCA to determine ongoing care
what is attenuated FAP (AFAP)
more than 10-20 adenomas but fewer than 100
older age
often right side
up to 80% risk of developing colorectal cancer at an average age of 56 years
screening for AFAP
suspect in individuals with more than 10 adenomas during lifetime
refer to hereditary cancer program at BCCA
what is HNPCC
aka lynch syndrome
refers to patients who fulfill amsterdam criteria for lynch syndrome
hereditary nonpolyposis colorectal cancer
what are the amsterdam criteria
for lynch syndrome
- at least 3 relatives with lynch syndrome assoc cancer (colorectal, endometrium, small bowel, ureter, renal pelvis)
- one is 1st degree relative of the other two
- at least two successive generations affected
- at least one dx before age 50
- FAP excluded in the colorectal cancer cases
- tumours verified with path
screening for HNPCC
if have family hx…colonoscopy beginning 10 years earlier than youngest age of family member dx or at age 25
colonoscopy every 2 years until age 40 then annually
refer to BCCA
what is the grading system of colon cancer
TNM staging
T1–no deeper than submucosa
T2–not through bowel wall
T3–through bowel wall
T4–through wall involving the serosa or adjacent structure
N1–regional lymph node mets (1-3 nodes)
M1–distant mets (lung, liver, bones) and/or positive peritoneal cytology and/or positive non-regional lymph nodes
what is the mainstay of curative colon cancer tx
surgery
removal of segment of colon or rectum and reconnect bowel if possible
what % of patients present with each stage of colon cancer
stage I–12%
stage II–24.5%
stage III–32/6%
stage IV–18.6%
what role does chemo play in colon chancer
for advanced or high risk tumours
after surgery
for killing cancer cells which may have spread
what role does radiation play in rectal cancer
only for rectal surgery
before surgery to shrink it
to reduce risk of cancer returning after surgery
what role does radiation play in rectal cancer
only for rectal surgery
before surgery to shrink it
to reduce risk of cancer returning after surgery
