Physical Examination for Suspected Colorectal Cancer
Perform a digital rectal examination (DRE) with rigid proctoscopy and obtain a tissue biopsy in every patient suspected of colorectal cancer, as histopathological confirmation is mandatory before initiating any treatment. 1, 2
Essential Components of the Physical Examination
Digital Rectal Examination and Rigid Proctoscopy
Conduct DRE to inspect and palpate the anus and lower rectum for masses, induration, or blood. 3, 1
Use rigid proctoscopy—not flexible sigmoidoscopy—to accurately measure the distance from the tumor to the anal verge, as this measurement determines whether the cancer is classified as rectal (≤15 cm) or colonic (>15 cm), which directly impacts treatment decisions including the need for neoadjuvant chemoradiotherapy. 1, 4, 2
Obtain a biopsy during rigid proctoscopy for histopathological confirmation, as no therapeutic decisions should be made without tissue diagnosis. 1, 2
Abdominal Examination
Palpate the abdomen systematically for masses, hepatomegaly, or discrete liver nodules that suggest hepatic metastases. 3, 1
Assess for abdominal distension, which has a positive likelihood ratio of 16.8 for bowel obstruction in patients presenting with obstructive symptoms from colorectal cancer. 3
Check for peritoneal signs (guarding, rebound tenderness, rigidity) that indicate perforation or ischemia, which are surgical emergencies. 3
Hernia Orifice Examination
- Examine all hernia orifices (umbilical, inguinal, femoral) and previous surgical scars carefully, as incarcerated hernias can present with bowel obstruction symptoms that may be confused with or coexist with colorectal cancer. 3
General Physical Assessment
Evaluate for signs of anemia including pallor, tachycardia, and conjunctival pallor, as 57-60% of colorectal cancer patients present with anemia. 3, 5
Assess for cachexia, weight loss, and general nutritional status as indicators of advanced disease. 3, 1
Palpate for supraclavicular lymphadenopathy (Virchow's node) and other peripheral lymph nodes to detect metastatic spread. 1
Check for ascites by percussion and fluid wave testing, which suggests peritoneal carcinomatosis. 1
Vital Signs Assessment
Measure vital signs including heart rate, blood pressure, respiratory rate, and temperature to identify signs of shock (tachycardia, tachypnea, hypotension) that may indicate bowel perforation, ischemia, or severe obstruction. 3
Assess skin temperature, capillary refill, and mental status as indicators of hemodynamic compromise. 3
Common Pitfalls and Clinical Pearls
Do not rely solely on flexible sigmoidoscopy for tumor localization; rigid proctoscopy provides the most accurate distance measurement from the anal verge, which is critical for treatment planning. 1, 2
Never postpone biopsy based on clinical suspicion alone—histopathological confirmation must precede treatment. 1, 2
Remember that digital rectal examination should be performed at the time of screening procedures (every 5-10 years), but there is no added benefit in detecting anal or rectal neoplasia by performing DRE more frequently than this interval in asymptomatic average-risk patients. 3
In elderly or unconscious patients, physical examination may be difficult; prioritize vital signs and cardiopulmonary assessment to identify critical conditions. 3
Recognize that rectal bleeding (58%), abdominal pain (52%), and change in bowel habits (51%) are the most common presenting symptoms, but anemia (57%) and occult bleeding (77%) are even more prevalent findings on examination. 6