Management of Rectal Villous Tumors




Introduction


The rectum, which is the organ of defecation, is a unique part of the gastrointestinal tract. The anatomic and physiologic characteristics peculiar to this role allow specific and sometimes unique approaches to management of neoplasms of the rectum. This chapter discusses options for the management of benign epithelial neoplasms in the rectum.




Rectal Anatomy and Physiology


The rectum consists of the lowest 8 inches of the intestinal tract. It is normally empty and therefore does not constantly engage in peristalsis. When filled with stool by a mass movement, the rectum contracts to expel the stool. Defecation is accomplished by the reflex relaxation of the internal anal sphincter and the voluntary relaxation of the external sphincter. Sometimes when defecation is not convenient and the external sphincter remains closed, the rectum accommodates its stool, with a temporary reduction in rectal pressure and closure of the anus. After a while, the rectal pressure rises again, although defecation is never as efficient later as it is with the initial urge.




Clinically Significant Associations of Rectal Function


This requirement for the rectum to both accommodate and expel stool is associated with a complete two-layer muscular coat that acts as a safeguard against polypectomy perforation. It also produces a mucosa that is more redundant than colonic mucosa and less tightly attached to the underlying muscularis propria, and thus it is more pliable and has a greater ability to be pulled into a snare. The lack of constant peristalsis encourages the development of large sessile (villous) lesions, and the extraperitoneal position of the lower half to third of the rectum minimizes the consequences of full-thickness excision.




Therapeutic Options Resulting from the Location of the Rectum


Several options are available for obtaining access to lesions of the rectum by virtue of the location of the rectum just above the anus, in the posterior pelvis. Rectal polyps can be approached transanally, through operating proctoscopes, or by transabdominal procedures. Surgeons therefore have the choice of a number of procedures for dealing with rectal villous tumors: direct transanal excision, endoscopic polypectomy through either flexible or rigid scopes, transanal endoscopic microsurgery (TEM), transanal minimally invasive surgery (TAMIS), a Delorme mucosal strip, trans-sacral approaches, and anterior resection. The advantages and disadvantages of these options are listed in Table 27-1 .



TABLE 27-1

Options for the Removal of Villous Tumors of the Rectum












































Procedure Indications Advantages Disadvantages
Endoscopic polypectomy Benign tumor
Any locations
Can remove large tumors
Low rate of complications
Outpatient
Inexpensive, with no special equipment required
Piecemeal resection is common
High recurrence
Transanal excision Low tumor (below the lowest rectal valve) Complete excision
Low recurrence
Inexpensive
No special equipment required
Can be difficult to perform
Stretches the anus
Requires general anesthesia
Transanal endoscopic microsurgery Any tumor, including T1, T2 cancer
Any location
Complete excision
Low recurrence
Costly
Equipment and training needed
Transanal minimally invasive surgery Any tumor, including T1, T2 cancer
Any location
Complete excision
Low recurrence
Costly
Specialized equipment and training needed
Delorme Benign tumor,
large and circumferential
Low complications
No anastomosis
Difficult to perform
Not possible in all patients
Trans-sacral Benign tumor in mid/upper rectum
No longer used
Avoids resection Possible parasacral fistula
Anterior resection Very large, circumferential tumors
Suspicious for cancer
Delorme procedure not possible
Complete clearance
Cancer not a concern
No recurrence
Major surgery
Hospitalization
Complications
Altered function

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Jul 15, 2019 | Posted by in GENERAL | Comments Off on Management of Rectal Villous Tumors
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