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Colorectal%20cancer Signs and Symptoms
Definition
- Carcinoma arising from the epithelial lining of the colon or of the rectum
- Incidence is higher in males
- Most colorectal cancers arise from adenomatous polyps
- Strongly linked to age, with 83% occurring in people ≥60 years old
- Rectal cancer is defined as cancerous lesions located within 12 cm of the anal verge (with rigid proctoscopy)
Signs and Symptoms
- Right-sided colonic lesions may present as:
- Vague abdominal pain
- Weight loss
- Anemia secondary to chronic blood loss
- Weakness
- Abdominal mass
- Left-sided colonic lesions may present as:
- Colicky abdominal pain
- Changes in bowel habits (constipation alternating with diarrhea) or narrowing of stools
- Obstructive symptoms like nausea and vomiting
- Lesions in the rectum may present as:
- Changes in bowel habits
- New onset or recurrent or persistent rectal bleeding
- Rectal urgency or fullness
- Tenesmus
Risk Factors
- Age: Chances are increased markedly after the age of 50
- Race: Colorectal cancer incidence and mortality rates are highest among African-Americans
- Personal history of colorectal cancer: Chances of developing new cancers in other parts of the colon or rectum is still possible even after removal of previous colorectal cancer; risk is increased in those who had their first colorectal cancer at a young age
- Personal history of colorectal polyps: Adenomatous polyps, especially multiple, large ones (>2 cm has a reported 40% chance of malignant transformation), increase the risk of developing colorectal cancer
- Malignant transformation is higher for villous and tubulovillous adenomas
- Familial adenomatous polyposis: Approximately 95% of FAP patients will develop adenomas by age 35 and if left untreated, has 100% chance of developing colorectal cancer
- Hereditary nonpolyposis colorectal cancer or hereditary nonpolyposis colorectal cancer (Lynch syndrome): Transmitted as an autosomal dominant trait
- Amsterdam II criteria identify high-risk families suspected of having hereditary nonpolyposis colorectal:
- Colorectal cancer affecting ≥2 generations
- ≥3 relatives with a histologically diagnosed hereditary nonpolyposis colorectal-associated cancer (eg colorectal cancer, small bowel, endometrial, renal pelvis or ureteral cancer)
- ≥1 colorectal cancers diagnosed at <50 years of age
- In suspected Lynch syndrome without a known familial mutation, first step in genetic diagnosis is identifying microsatellite instability in tumor cells
- Amsterdam II criteria identify high-risk families suspected of having hereditary nonpolyposis colorectal:
- Personal history of inflammatory bowel disease (ulcerative colitis, Crohn’s disease): Increases risk for colorectal cancer; colorectal screening should be done more frequently
- Risk of colorectal cancer in a patient with ulcerative colitis depends on extent of colitis, duration of active disease and symptoms, development of mucosal dysplasia
- Risk of colorectal cancer in Crohn’s disease is also increased but to a lesser extent
- In patients with ulcerative colitis, overall incidence of colorectal cancer is 3.7%, with 2% probability by 10 years, and 8% by 20 years
- In patients with Crohn’s colitis, risk for colorectal cancer is similar while it appears that there is no significant risk associated with proctitis
- Family history of colorectal cancer: Risk is highest in those with >1 affected first-degree relative (parent, siblings) or in those whose first-degree relative had colorectal cancer at a young age
- Type 2 diabetes mellitus: Increases the risk of colorectal cancer and tends to have a less favorable prognosis
- Diet: Consumption of red and processed meats, fat and cholesterol-rich diets have been linked to an increased risk of colorectal cancer
- Heavy alcohol consumption: Increased risk of colorectal cancer is probably due to low levels of folic acid among heavy drinkers
- Obesity
- Both overweight and obese people are at increased risk of colorectal cancer
- Pattern of fat distribution relates to the colorectal cancer risk (abdominal obesity being a stronger risk factor than truncal obesity or BMI)
- Obesity approximately increases by 2x the risk of adenomas (particularly, ≥1 cm, tubulovillous adenomas)
- Smoking: Studies of recent years have found association between smoking and colorectal cancer, with relative risks between 1.5-3
- Sedentary lifestyle
