A 55-year-old man was referred to surgeon because he has become increasingly constipated over the last 2 months. This has occurred despite attempts to increase fiber in his diet and to markedly increase his physical activity. Laxatives have been mostly ineffective. On fuher questioning, the man repos that he has twice seen fresh blood on his stools, which he attributed to hemorrhoids. He has also noticed a sense of fullness and discomfo in his lower left abdominal quadrant, but attributed these findings to his constipation. Digital examination is negative. Colonoscopy demonstrates an area of stricture with surface ulceration 10 cm above the anal verge. The distal colon is surgically resected. Pathologic examination demonstrates a napkin-ring lesion with marked thickening of the mucosal layer of the rectum. On cross- section, the lesion is seen to extend through the rectal muscle and into, but not through, the adjacent serosal adipose tissue. Fuher evaluation fails to demonstrate the patient's disease in either lymph nodes or distant sites. This patient's disease would be staged as which of the following?
The Duke's classification is commonly used for staging of colorectal carcinoma. This patient has stage B2, characterized by invasion through the muscularis propria and without lymph node involvement or distant metastases. Duke's classification B2 has a 55-65% 5-year survival rate. Duke's classification A has tumor limited to the mucosa with no metastatic disease, and has a 5-year survival of more than 90%. Duke's classification B1 has invasion into the muscularis propria, but no lymph node or distant metastases; this stage has a 5-year survival of 70-85%. Duke's classification C1 has invasion into the muscularis propria and lymph node but not distant metastatic disease; the 5-year survival is 45-55%.
Duke's classification A
Duke's classification B1
Duke's classification B2
Duke's classification C1