SM_165: Colorectal Cancer Flashcards
____ is the third most common cancer for men and women and second leading cause of cancer death for men and women
Colorectal cancer is the third most common cancer for men and women and second leading cause of cancer death for men and women
- Highest in North America, Western Europe, Australia, New Zealand
- Decreasing incidence and mortality
- Worse survival in LMICs
- Racial / ethnic disparities
Risk factors for colorectal cancer are ____, ____, ____, ____, and ____
Risk factors for colorectal cancer are
- Increasing age: most cases after age 50
- Diet and environment: high fat, low fiber, and obesity
- Family history: risk increases with number of affected family members
- Prior history of colorectal cancer / polyps and large polyps
- IBD: mainly ulcerative colitis
Colorectal cancer syndromes include ____ and ____
Colorectal cancer syndromes include familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer (Lynch syndrome)
- Familial risk
Most colorectal cancers arise from ____
Most colorectal cancers arise from adenomas following a pathway with several genetic mutations
- Mutations occur at the germline level
- Most sporadic cancers follow a pathway similar to familial adenomatous polyposis
Describe the pathogenesis of colorectal cancer
Colorectal cancer pathogenesis
- Normal colon
- Small adenoma
- Large adenoma with villous component
- Large adenoma with high grade dysplasia
- Large adenoma with invasive carcinoma
Familial adenomatous polyposis is an ____ syndrome caused by a mutation in the ____ gene
Familial adenomatous polyposis is an autosomal dominant syndrome caused by a mutation in the APC (adenomatous polyposis coli) gene
- Classic form characterized by hundreds-thousands of polyps
- Polyps develop early (teens) and lifetime risk of colorectal cancer approaches 100%
- Treatment: subtotal or total colectomy
- Genetic testing useful for diagnosis and screening
Lynch syndrome (hereditary nonpolyposis colorectal cancer) is an ____ syndrome caused by a mutation of ____ genes
Lynch syndrome (hereditary nonpolyposis colorectal cancer) is an autosomal dominant syndrome caused by mutation of MMR (mismatch repair) genes
- Few or no polypoid adenomas, tumors may arise from flat or depressed adenomas
- After colorectal cancer diagnosis, treatment usually involves subtotal colectomy
- Generic testing used for diagnosis and screening
Lynch syndrome (hereditary nonpolyposis colorectal cancer) also involves ____ malignancy
Lynch syndrome (hereditary nonpolyposis colorectal cancer) also involves extracolonic malignancy
- Hepatobiliary
- Stomach
- Small bowel
- Endometrium
- Uroepithelium
- Ovary
- Keratoacanthomas / sebaceous gland neoplasia (Muir-Torre syndrome
Symptoms and signs of colorectal cancer are ____, ____, ____, ____, and ____
Symptoms and signs of colorectal cancer are abdominal / rectal pain, change in bowel movement pattern, hematochezia (blood per rectum), anemia (often of iron deficiency), and weight loss / fatigue / obstruction
____ colorectal tumors are less likely to obstruct the lumen and more likely to cause chronic blood loss and presentation with fatigue and anemia
Right side colorectal tumors are less likely to obstruct the lumen and more likely to cause chronic blood loss and presentation with fatigue and anemia
____ colorectal tumors may cause obstructive symptoms and present with hematochezia
Left side tumors colorectal tumors may cause obstructive symptoms and present with hematochezia
- Change in bowel movement pattern, pain, or frank obstruction
Rectal cancers may present with ____
Rectal cancers may present with local pain
Colorectal cancer should be considered especially if ____, ____, ____, or ____
Colorectal cancer should be considered especially if
- Recent onset of symptoms
- Patient older than 40
- FMHx of colorectal cancer or polyps
- Iron deficiency anemia in men or postmenopausal women
Evaluation of colorectal cancer involves ____, ____, and ____
Evaluation of colorectal cancer involves colonscopy, flexible sigmoidoscopy, and air contrast barium enema
- Colonscopy: preferred method to evaluate lumen, allows for localization of lesions / biopsy / polyp removal
- Flexible sigmoidoscopy: diagnoses lesions in left side of colon up to splenic flexure
- Air contrast barium enema: useful if colonoscopy not feasible (tortuous sigmoid, stricture, obstructing mass) but not as sensitive for smaller lesion
Describe clinical staging of colorectal cancer
Clinical staging of colorectal cancer
- Established by biopsy of colorectal lesions
- Staging required to direct treatment
- Initial staging is clinical (pathological staging requires surgical specimen)
- Usually includes physical exam and CT scan of abdomen and pelvis (to detect local extension, abnormal lymph nodes, and distant metastases), CXR, liver enzymes, carcinoembryonic antigen
Rectal cancer is ____ to spread locally and has ____ risk of local recurrence than colon cancer
Rectal cancer is more likely to spread locally and has higher risk of local recurrence than colon cancer
- Need to evaluate preoperatively to determine depth and lymph node involvement
- Endoscopic ultrasound is useful to assess depth of involvement and presence of lymph nodes and allows fine needle aspiration to confirm tumor involvement in suspicious nodes
____ staging is used for colorectal cancer
TNM staging is used for colorectal cancer
____ is the treatment of choice for the vast majority of colorectal cancers
Surgery is the treatment of choice for the vast majority of colorectal cancers
____ is used for adjuvant treatment of patients with colorectal cancer who undergo potentially curative resection but have higher risk of recurrence, such as stage III colon cancer and stage II or III rectal cancers
Chemotherapy is used for adjuvant treatment of patients with colorectal cancer who undergo potentially curative resection but have higher risk of recurrence, such as stage III colon cancer and stage II or III rectal cancers
- 5-FU and leucovorin, w/ or w/o oxaliplatin
___ is used to treat stage II or III rectal cancer usually in combination with chemotherapy
Radiotherapy is used to treat stage II or III rectal cancer usually in combination with chemotherapy
- Adjuvant or neoadjuvant therapy as well
- Only used for select colon cancer cases with high risk of local recurrence (e.g. perforation, invasion into adjacent organs)
____ can be used to relieve colorectal obstruction
Endoscopic stenting can be used to relieve colorectal obstruction
Summarize colorectal cancer treatment
Colorectal cancer treatment
Higher stage colorectal cancer is associated with ____ prognosis
Higher stage colorectal cancer is associated with poorer prognosis
Goals of colorectal cancer screening are ____ and ____
Goals of colorectal cancer screening are detection of colorectal cancer at early stages to reduce morbidity and mortality and detection and removal of pre-malignant polyps to reduce the incidence of colorectal cancer
FOBT/FIT is based on the rationale that ___
FOBT is based on the rationale that most colorectal cancers bleed so large polyps may also bleed
- Does not distinguish between bleeding from cancer / polyps and from other GI lesions
- False positives with certain foods and rare red meets
- False negatives with intermittent or insufficient bleeding, delay of assay, or sampling error
Fecal DNA test tests for ____
Fecal DNA test tests for common fecal DNA mutations associated with colorectal neoplasia
Positive FOBT leads patients to obtain a ____
Positive FOBT leads patients to obtain a colonoscopy
Flexible sigmoidoscopy ____
Flexible sigmoidoscopy detects only about 50-70% of all colorectal cancers and polyps because only left side of colon is examined
- Distal polyps predict proximal polyps / cancer
- Allows direct visualization of bowel mucosa and biopsy of lesions
- If positive, get colonscopy
Colonoscopy allows ____ and ____
Colonoscopy allows direct inspection of colorectal mucosa for the entire colon and opportunity for biopsy / removal of lesions (polypectomy)
- Usually need sedation
- Risk of perforation
____ is performed after bowel preparation, involves computer enhanced CT scan, and does not allow for biopsy
CT colongraphy is performed after bowel preparation, involves computer enhanced CT scan, and does not allow for biopsy
If a capsule colonscopy identifies a lesion, ____ is required
If a capsule colonscopy identifies a lesion, colonscopy is required
- Ingestion of a video capsule and use of the images obtained during passage to detect neoplasia
Colorectal cancer screening begins at ____ and ____
Colorectal cancer screening begins at age 45 for African Americans and age 50 for all other races
- Discontinue in ≥ 75 years with prior negative screening, patients whose life expectancy < 10 years, and patients ≥ 85 years without prior screening
Screen for colorectal cancer more regularly in people with ____, ____, and ____
Screen for colorectal cancer more regularly in people with history of colorectal cancer / polyps, IBD for >8-10 years, and familial syndromes
