List constitutional symptoms.
Abdominal discomfort (symptoms similar to diverticulitis, especially in carcinoma of the rectosigmoid or descending colon
List symptoms of right-sided colon carcinomas (~38%).
Definition: large bowel malignancies arising from the cecum, ascending colon, or transverse colon
Occult bleeding or melena
Manifestations of iron deficiency anemia (due to chronic bleeding)
List symptoms of left-sided colon carcinomas (~28%).
Definition: large bowel malignancies arising from the splenic flexure, descending colon, sigmoid colon, or the rectosigmoid junction
Changes in bowel habits (size, consistency, frequency)
Colicky abdominal pain (due to obstruction)
List symptoms of rectal carcinomas (~34%).
Definition: large bowel malignancies located ≤ 15 cm from the anal verge 
↓ Stool caliber (pencil-shaped stool)
List clinical features of metastatic disease.
CRC can metastasize through hematogenous, lymphatic, transperitoneal, and contiguous routes. Symptomatic metastases may be the first manifestation of CRC.
Liver metastases (most common site of metastasis; 40–50%)
Ascites, abdominal distention
Hepatomegaly, RUQ pain
Anorexia, early satiety
Ascites, abdominal distension, diffuse abdominal pain
Evidence of distant lymphatic spread: Virchow node (rare)
List red flags for colorectal cancer.
Altered bowel habits
Unexplained weight loss
Unexplained iron deficiency anemia, especially in men older than 50 years of age and postmenopausal women
Why does bowel obstruction occur earlier in left-sided colon carcinomas?
Because the distal colon has a smaller lumen than the proximal colon and contains solid fecal matter.
Where do cacers of the colon and upper rectum vs. lower rectum initially metastasize to?
Typically, cancers of the colon and upper rectum initially metastasize to the liver via the portal vein, and cancers of the lower rectum initially metastasize to the lung via the inferior vena cava.