Colorectal Cancer Flashcards
What does colon cancer normally begin with?
- Almost all cancers are thought to arise from a polyp
What are some risk factors for developing colon cancer?
A. Age
a. Rises sharply after 45, and almost all cases occur over the age of 50
B. Fam Hx
C. Inflammatory Bowel Disease
a. Begins to rise about 8 years past the onset of Crohns or UC. Screening is important
D. Dietary Factors and Chemoprevention
a. Diets rich in red meat and fats are associated with colorectal carcinomas.
b. Diets high in fruits, veggies, and fiber are at a decreased risk
c. Prolonged NSAID use is also associated
E. Other Factors
a. Blacks > whites
b. DM, smoking, metabolic syndrome associated
What KIND of cancer is most colon cancer?
adenocarcinoma. It tends to be slower growing.
What are some clinical signs that you may have a Right sided colon cancer?
chronic blood loss→ anemia, fatigue, weakness
What are some clinical signs that you might have a left sided colon cancer?
Left Sided Colon Cancers: smaller in diameter, often involved obstructive symptoms: colicky pain, change in bowel habits. Sometimes stool is marked blood, although not required
What will a physical exam reveal for colon cancer?
Physical Exam is usually unremarkable until late in the disease. Sometimes a palpable mass is felt
What are the two types of colorectal polyps?
- hyperplastic –> not cancerous precursor
2. adenoma –> important precursor
Cancer arises from what type of polyp? How can risk of cancer be reduced?
most arise from adenomatous polyps, and you should excise them to decrease risk.
What labs are indicated in colon cancer?
a. CBC → anemia
b. Elevated liver tests→ (esp alkaline phosphatase) usually suspicious for metastizes.
c. CEA level
i. Should normalize after resection
ii. >5 ng/mL is not a good prognosis
What is Familial Adenomatous Polyposis syndrome?
It is an autosomal dominant disease. It is on chromosome 5q APC gene. By age 30-40, there are 100’s of adenomas present in the colon. If this goes untreated, by age 40-50 there is a 100% chance of colon cancer. Tx: removal of colon
What is HNPCC or Lynch Syndrome?
It is a hereditary non polyposis colorectal cancer. It accounts for 5-10% of colon cancer. Familes with HNPCC have a 70-90% chance of developing colorectal cancer. Usually diagnosed with colon cancer around 45 years old. Genetic testing is available.
What are some symptoms of colon cancer?
change in bowel habits, bright red or dark stool, stools that appear narrow or thinner than others, discomfort in the abdomen, including frequent gas, pains, bloating, fullness and cramps. Unexplained weight loss, tiredness.
What is the number one best way to screen for colon cancer?
colonoscopy
Where are most colon cancers located?
2/3 are found in the descending colon
What are the current guidelines for screening of colon cancer?
M and W after age 50…
1. fecal occult blood test annually or flexible sigmoidoscopy every 5 years
or
2. colonscopy every 10 years
or
3. double contrast barium enema every 5 years.
what are the screening recommendations for those with increased with of colon cancer?
If…
- 1 cm adenoma or multiple adenoma…repeat with 3 years, again in 3, and if normal then 5-10
- history of curative intent resection of the colon….on year after surgery, 3 years, then every 5
- 1st degree relative with colon CA or adenomatous polyps before age 60 or two 1st degree relatives of any age with colon cancer…colonscopy at age 40 or 10 years prior to youngest affected kin and repeat every 5-10.
What should the screening be for those with history of FAP OR HNDCC OR IBD?
FAP: begin at puberty, if found then coloectomy
HNDCC: screen at 21, then every two years tip 40, then yearly
IBD: 8 years after diagnosed pan colitis or 12-15 after left sided colitis.
What staging system is used for colon cancer?
TNM
Describe Stage 0 colon cancer
known as cancer “in situ”, meaning the cancer is located in the mucosa. Removal of the polyp is the usual treatment.
Describe Stage 1 colon cancer
Cancer has grown into the mucosa and invaded the muscular is. Treatment is surgery and to remove the tumor and surrounding lymph nodes. high survival rate.
Describe Stage 2 colon cancer
Cancer has grown beyond the muscular is of the colon or rectum but has NOT spread to the lymph nodes. Treatment is surgery, and sometimes chemo. Stage two rectal cancer is treated with surgery, radiation, and chemo.
Describe Stage 3 colon cancer
The cancer has spread to the regional lymph nodes. Treated by surgery and chemo. Stage three rectal is treated with surgery, radiation and chemo. survival is very variable.
Describe Stage 4 colon cancer
the cancer has spread outside of the colon or rectum to other areas of the body. treated by chemo. surgery to remove colon may or may not be done. Typically less than 10% survival.
What is a differential diagnosis for colon cancer?
a. The non specific symptoms of colon cancer may be confused with IBS, diverticular disease, ischemic colitis, IBD, infectious colitis, and hemmorhoids.
b. Cancer must be excluded in those over 40 with reports of change in bowel habits, or hematochezia or who has unexplained IDA or occult stool samples.
