Abdominoperineal resection is done in colorectal carcinoma on the basis of:
**Core Concept**
Abdominoperineal resection (APR) is a surgical procedure for treating rectal cancer that involves removing the rectum, anus, and a portion of the sigmoid colon. The decision to perform APR is based on the location and extent of the tumor, as well as the patient's overall health and medical history.
**Why the Correct Answer is Right**
The primary indication for APR is the presence of a rectal cancer that is too close to the anus to allow for a sphincter-sparing procedure, such as low anterior resection. The tumor's location is critical in determining the best surgical approach, as APR is typically reserved for tumors that are within 5-6 cm of the anal verge. This is because APR involves the removal of the anus and sphincter muscles, resulting in a permanent colostomy.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because APR is not typically performed for colon cancer that has not invaded the rectum. The procedure is specifically reserved for rectal cancer that is too close to the anus to allow for a sphincter-sparing procedure.
**Option B:** This option is incorrect because APR is not typically performed for rectal cancer that is amenable to sphincter-sparing procedures, such as low anterior resection. These procedures aim to preserve the anal sphincter and avoid the need for a permanent colostomy.
**Option C:** This option is incorrect because APR is not typically performed for rectal cancer that is located in the upper or middle rectum. Tumors in these locations may be amenable to sphincter-sparing procedures, such as low anterior resection.
**Clinical Pearl / High-Yield Fact**
A key factor in determining the best surgical approach for rectal cancer is the tumor's location relative to the anal verge. Tumors within 5-6 cm of the anal verge are typically best treated with abdominoperineal resection, while tumors located higher in the rectum may be amenable to sphincter-sparing procedures.
**Correct Answer:** D.