COLON CANCER (TB) Flashcards
Which malignancy is increasingly seen in younger patients
and why is early screening important?
What is the second leading cause of cancer death in the United States?
Colorectal cancer (second to lung cancer).
What trend is observed in colorectal cancer incidence among individuals under 50 without family history?
Incidence has risen by 2% each year.
Why do younger colorectal cancer patients tend to present with more advanced disease?
They often dismiss symptoms like hematochezia
What is the rank of colorectal cancer in terms of incidence across all age groups?
Third (1st: Breast
What is the second leading cause of cancer death in both sexes across all age groups?
Colorectal cancer.
What type of polyps are the most common precursor to colorectal cancer?
Adenomatous polyps.
Do most polyps cause symptoms?
No
What percentage of middle-aged individuals have adenomatous polyps?
About 30%.
What percentage of elderly individuals have adenomatous polyps?
About 50%.
What percentage of polyps become malignant?
Less than 1%.
Why does a negative FOBT not rule out polyps?
Bleeding from polyps is intermittent.
What increases the risk of malignancy in a polyp?
Polyp size.
What genetic mutation is associated with colorectal cancer in the K-ras gene?
Point mutation in K-ras proto-oncogene.
What genetic alteration involves the APC gene in colorectal cancer?
Allelic loss at 5q21.
What gene on chromosome 18q is frequently lost in colorectal cancer?
DCC gene (Deleted in Colorectal Cancer gene).
What gene mutation on chromosome 17p is associated with colorectal cancer?
p53 tumor suppressor gene mutation.
What is the adenoma to carcinoma sequence?
A progression from normal epithelium to hyperproliferation
What are the two major types of polyps?
Pedunculated (with stalk) and Sessile (directly attached).
What are the histologic classifications of adenomatous polyps?
Tubular
Which type of adenomatous polyp has the highest malignancy potential?
Villous adenomas.
What is the malignancy risk for a polyp <1.5 cm?
Less than 2%.
What is the malignancy risk for a polyp 1.5-2.5 cm?
2-10%.
What is the malignancy risk for a polyp >2.5 cm?
About 10%.
What dietary factors increase the risk of colorectal cancer?
Animal fat
Which hereditary syndromes increase colorectal cancer risk?
Familial adenomatous polyposis
Which inflammatory condition significantly increases colorectal cancer risk?
Ulcerative colitis.
Which bacterium is associated with colorectal cancer?
Streptococcus bovis.
What lifestyle factors increase colorectal cancer risk?
Obesity
What common dietary pattern is associated with increased colorectal cancer risk?
Western diet (high in red/processed meat
What modifiable factor contributes to increased risk through insulin resistance?
Obesity.
What growth factor promotes colonic mucosal proliferation in obesity?
Insulin-like growth factor 1 (IGF-1).
What is the recommended window of opportunity to remove polyps before malignancy?
5 years.
What medications are associated with decreased colorectal cancer risk?
Aspirin
What supplements may reduce colorectal cancer risk?
Calcium
What food groups decrease colorectal cancer risk?
Dairy products
What type of physical activity decreases colorectal cancer risk?
Vigorous physical activity.
What is the characteristic polyp distribution in Familial Adenomatous Polyposis (FAP)?
Large intestine
What non-GI tumors are associated with Gardner’s syndrome?
Osteomas
What brain tumors are associated with Turcot’s syndrome?
Brain tumors (e.g.
What is the polyp distribution in Lynch syndrome?
Proximal colon (right-sided).
Which extracolonic cancers are associated with Lynch syndrome?
Endometrial
What distinguishing feature is associated with Peutz-Jeghers syndrome?
Mucocutaneous pigmentation (lips) and GI hamartomatous polyps.
What extracolonic cancers are associated with Peutz-Jeghers syndrome?
Breast
What type of polyps are found in Juvenile Polyposis?
Hamartomatous polyps (rarely progress to adenomas).
What dietary mechanism links animal fat to colorectal cancer risk?
Gut microbiome alteration converting bile acids into carcinogens.
How does insulin resistance contribute to colorectal cancer risk?
Increased insulin and IGF-1 levels promote colonic mucosal proliferation.
What dietary components have limited suggestive evidence for decreasing colorectal cancer risk?
Vitamin C
What dietary factors have limited evidence suggesting increased colorectal cancer risk?
Heme iron
What is the histologic type of polyps in Familial Adenomatous Polyposis?
Adenomatous polyps.
What is the malignant potential of polyps in Peutz-Jeghers syndrome?
Rare.
What is the malignant potential of polyps in Lynch syndrome?
Common.
What type of polyp requires histologic evaluation after removal?
Any adenomatous polyp.
What are the two main pathways leading to colorectal cancer?
Adenoma-carcinoma sequence
What dietary pattern can reduce colorectal cancer risk?
High intake of fruits
What is the inheritance pattern of familial adenomatous polyposis (FAP)?
Autosomal dominant
What gene is mutated in familial adenomatous polyposis (FAP)?
APC gene
On which chromosome is the APC gene located?
Chromosome 5
What syndrome is associated with colonic polyps
soft tissue and bony tumors
What syndrome features colonic polyps and malignant CNS tumors?
Turcot’s Syndrome
At what age do colonic polyps in FAP typically present?
Before age 25 years
By what age do FAP patients typically develop colorectal cancer if untreated?
Before age 40 years
What medications can reduce the number and size of polyps in FAP?
NSAIDs and COX-2 inhibitors
What is the primary treatment for FAP?
Total colectomy
What is the recommended screening for offspring of FAP patients?
Annual flexible sigmoidoscopy until age 35 years
Why is flexible sigmoidoscopy preferred over colonoscopy in FAP screening?
Thousands of equally distributed polyps are easily visualized with sigmoidoscopy
Is fecal occult blood testing (FOBT) adequate for screening in FAP?
No
How can a definitive diagnosis of FAP be made before polyps develop?
APC gene mutation testing from peripheral blood
What is the inheritance pattern of MYH-associated polyposis?
Autosomal recessive
What gene is mutated in MYH-associated polyposis?
MUT4H gene
What is the recommended surveillance for MYH-associated polyposis?
Colonoscopy every 1-2 years starting at age 25-30 years
What is the inheritance pattern of Lynch syndrome?
Autosomal dominant
What is another name for Lynch syndrome?
Hereditary nonpolyposis colorectal cancer (HNPCC)
What family history pattern is required to diagnose Lynch syndrome?
3 relatives with CRC
Which part of the colon is most affected in Lynch syndrome?
Proximal colon
At what age does CRC typically present in Lynch syndrome?
Younger than 50 years old
What is the prognosis for proximal colon tumors in Lynch syndrome?
Better prognosis due to earlier diagnosis
What other cancers are associated with Lynch syndrome?
Endometrial
What is the recommended screening for Lynch syndrome?
Colonoscopy every 1-2 years starting at age 25
What two genes are commonly mutated in Lynch syndrome?
hMSH2 and hMLH1
What molecular test can be done to detect Lynch syndrome?
Microsatellite instability testing
Which has a higher CRC risk: ulcerative colitis (UC) or Crohn’s disease (CD)?
Ulcerative colitis
What factors increase CRC risk in IBD patients?
Long disease duration
What bacterial infection is linked to colorectal cancer?
Streptococcus bovis bacteremia
How does tobacco use affect colorectal cancer risk?
> 35 pack-years increases CRC risk
What medications may prevent colorectal cancer?
Aspirin and NSAIDs
How do aspirin and NSAIDs reduce colorectal cancer risk?
Inhibit prostaglandin synthesis and suppress cell proliferation
What criteria must a patient meet before taking aspirin for CRC prevention?
Low bleeding risk
What vitamin may have a protective effect against colorectal cancer?
Vitamin D
How might estrogen therapy protect against colorectal cancer?
Alters bile acid synthesis and decreases IGF-1 levels
At what age should average-risk adults begin colorectal cancer screening?
45 years old
What colorectal cancer screening is recommended for average-risk adults 50-75 years old?
Colonoscopy every 10 years or annual FIT
Should screening be individualized for adults aged 76-85 years?
Yes
Should adults >85 years be screened for colorectal cancer?
No
How often should sigmoidoscopy be done for CRC screening?
Every 5 years
How often should FIT (fecal immunochemical test) be done for CRC screening?
Every year
How often should colonoscopy be done for average-risk adults?
Every 10 years
How often should fecal DNA testing be done for CRC screening?
Every 3 years
How often should CT colonography be done for CRC screening?
Every 5 years
What are some alarm symptoms that warrant colorectal cancer screening?
Anemia
What screening test is recommended for family history of CRC at age <60?
Colonoscopy every 5 years starting at age 40
What screening is recommended for first-degree relatives of CRC patients diagnosed ≥60?
Colonoscopy every 10 years starting at age 40
When should FAP screening with sigmoidoscopy start?
Age 10-12 years
When should Lynch syndrome screening start?
Colonoscopy every 1-2 years starting at age 20-25 years
What surveillance is recommended for serrated polyposis syndrome?
Colonoscopy every 1-2 years
How often should patients with long-standing ulcerative pancolitis undergo surveillance?
Colonoscopy with biopsies every 1-2 years
What advanced imaging technique can enhance dysplasia detection in IBD surveillance?
Chromoendoscopy
When should colonoscopy follow-up occur after removal of 1-2 small adenomas?
In 5-10 years
When should follow-up colonoscopy occur after removal of >10 adenomas?
In less than 3 years
What is the recommended follow-up for incomplete removal of large serrated polyps?
Repeat colonoscopy in 2-6 months
What should be done for patients with personal history of CRC after resection?
Colonoscopy 1 year after resection
