Sphincter-Preserving Techniques in Rectal Cancer Surgery

Introduction

The goal of surgery for rectal cancer is to remove the tumor completely while maintaining the function of the anal sphincter and the integrity of the colon. Rectal cancer treatment has advanced significantly in the last few decades, mainly due to the introduction of Total Mesorectal Excision (TME) and Neoadjuvant Chemoradiotherapy (nCRT) for regionally advanced cancers. Patients with rectal cancer have more opportunities to preserve their sphincters when TME and nCRT are combined, as they also significantly lower the rates of local recurrence.

What Is Sphincter?

The anal sphincter is a group of muscles at the end of the rectum that controls the release of stool and thus maintains continence. The rectum in an adult is around 4.7 inches long on average. The anal sphincter is located in the lowest region of the rectum. The internal and external anal sphincters are two muscles involved. The process known as the anal sphincter reflex happens when feces pass through the digestive system and causes the internal anal sphincter to relax and the external anal sphincter to contract. The defecation reflex is another name for this reaction. The internal and external anal sphincters collaborate to create a bowel movement but in opposite ways.

What Is Rectal Cancer?

A cancer that originates in the rectum is known as rectal cancer. A few inches at the end of the large intestine is known as the rectum. It ends when it reaches the short, constricted passageway that leads to the anus and begins at the end of the colon. However, colon and rectal cancers share many characteristics but are treated differently. This is predominantly due to the small size of the rectum and its proximity to other organs and structures. Rectal cancer removal surgery may be complicated because of the limited space.

Men are slightly more likely to get rectal cancer when compared to women, but both sexes are affected by the disease. People over 50 are typically the ones diagnosed with the illness. However, rectal cancer can also strike teenagers and young adults. Rectal cancer affects about 5 % of people at some point in their lives. Roughly 11 % of those individuals are younger than 50.

How Was Rectal Cancer Treated Previously?

In the past, abdominoperineal resection (APR, the complete removal of the distal colon, rectum, and sphincter) was the gold standard for treating rectal cancer. Ernest Miles initiated and advocated this procedure for many years. It was around the mid-1900s that this started to change. APR is still useful in the treatment of rectal cancer. Still, for patients receiving care from skilled surgeons, the percentage of patients who require a permanent colostomy should be much lower than thirty percent.

Why Is Abdominoperineal Resection Less Preferred?

The abdominoperineal resection has become less popular due to several reasons:

1. A better understanding of the radial or deep margin and what is required for a distal margin.

2. Technological advancements in surgery.

3. A better understanding of reconstruction so that a good functional outcome is obtained.

4. The significance of the appropriate use of multimodality chemotherapy and radiation therapy as a means of improving overall survival and reducing local failure rates

5. A recognition of the importance of proper surgical technique and the necessity of a total mesorectal excision for mid and rectal cancers.

What Is Sphincter-Preserving Surgery for Rectal Cancer?

The sphincter is kept intact while the colon or rectum is removed in sphincter-sparing colorectal surgery. This procedure is called proctectomy. The rectum's location within the pelvic bony structures can make the procedure difficult, even for skilled surgeons.

• Colon to Anus (Colo-anal) Anastomosis: Usually located between the colon and the anus, the rectum holds stool until it is time for a bowel movement. In this procedure, the bottom of the colon is connected to the top portion of the rectum. The colon tissue is used to construct a pouch that holds the stool until defecation (the process by which stool is removed from the body).

• Small Bowel Pouch to Anus (Ileoanal or J-Pouch) Anastomosis: The colon aids in removing stool by joining the small intestine to the colon. Ileoanal anastomosis is utilized to join a portion of the small intestine called the ileum to the anus if the colon and rectum need to be removed.

• Transanal Minimally Invasive Surgery (TAMIS): A procedure that facilitates the excision of tumors that cause trouble and precancerous growths or polyps in the colon and rectum is called TAMIS. With TAMIS, the polyp or tumor is removed using laparoscopic instruments that are inserted through the anus.

• Transanal Total Mesorectal Excision (TaTME): This procedure is similar to TAMIS, except that the surgical area is assessed through the anus. The polyps or tumors are accessed through two angles using minimally invasive techniques like a laparoscopy or robotic surgery. This procedure is faster and helps eradicate the tumor in areas with limited access.

What to Expect During a Sphincter-Preserving Colorectal Surgery?

During a sphincter preserving procedure, two body structures are connected surgically. In some advanced conditions, the colon or rectum removal might be required. By joining the remaining sections of the healthy intestine, anastomosis facilitates the normal passage of waste and feces out through the anus. The trouble of having a permanent stoma can be stopped by undergoing the procedure. An anus and rectum can be bypassed by a stoma, a surgically made opening that empties waste into a designated bag. In a sphincter preserving procedure, the affected areas are removed using minimally invasive procedures while the patient is under general anesthesia, saving the sphincter.

Conclusion

Abdominoperineal Resection (APR) was the standard treatment for rectal cancer for many years. Several novel approaches to treating rectal cancer patients have surfaced in recent years, intending to maintain gastrointestinal continuity and enhance both the functional and oncological results. A personalized strategy based on specific pathological prognostic factors and current guidelines is required to achieve the best possible outcome for each patient. While APR is still valid in treating rectal cancer, sphincter-preserving resection is currently the preferred course of treatment in a majority of patients. Even the smallest tumors can be operated on using these techniques.