NMS. Casos Clínicos

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Part II ♦ Specific Disorders

Q: What further evaluation is necessary before making a decision regarding treatment? A: The following studies are necessary. Colonoscopy is necessary initially for visualization of the entire colon to rule out the presence of synchronous lesions. If no other lesions are found, an evaluation determines the depth of invasion that is warranted; this is an import- ant prognostic sign. Transrectal ultrasound is useful to determine rectal wall invasion and local lymph node enlargement. CT or magnetic resonance imaging (MRI) is appropriate to determine whether adjacent structures , including the prostate, bladder, and ureters, are involved. CT scans may show distant involvement in the liver, as well as enlarged lymph nodes. A CXR and a CEA level are also warranted before surgery. After studying this patient, you find that there is a circumferential lesion 4 cm from the anal verge that is not fixed to the surrounding tissues. The transrectal ultrasound indicates that the tumor is limited to the bowel wall, and no regional or local lymph nodes are evident. The CT scan shows a normal liver and no other abnormalities. The CXR is normal. The CEA is elevated, and all other laboratory studies are normal. Q: What is the next step? A: Resection of the tumor is warranted, assuming that the patient is an acceptable operative risk. Preoperative neoadjuvant therapy is not useful in this early-stage lesion. Q: What procedure is appropriate? A: Most surgeons would recommend an abdominoperineal resection, which involves excision of the entire rectum with the creation of a permanent colostomy (Figs. 8-26 and 8-27). In addition, this procedure removes local lymph nodes. Q: The patient’s tumor metastasizes to what nodal locations and other organs? A: Rectal carcinomas spread by direct extension and lymphatics. Lymphatic spread parallels the superior hemorrhoidal vessels and includes the internal iliac nodes, sacral nodes, and inferior mesenteric nodes . Lesions less than 5 cm from the anal verge can also spread locally and to the inguinal nodes , and this should be determined preoperatively. Distal organ involvement most commonly includes the liver or adjacent structures. Q: What information should the patient receive about the perioperative risks and complications of abdominoperineal resection? A: Several specific complications relate to abdominoperineal resection. Because the sympa- thetic plexus of nerves is located around the rectum, the chance of impotence following the procedure is high. It is essential that the patient be told prior to surgery about the possibility of impotence. There is also a chance that bladder function may be impaired following sur- gery. Other intraoperative risks include massive venous bleeding from the presacral space and injury to the ureter. Finally, a variety of colostomy complications, including retraction, prolapse, stricture, and obstruction, may occur. A: The basic principle of the abdominoperineal resection is removal of the entire rectum in continuity with its vascular and lymphatic supply. It is necessary to mark a colostomy site SAMPLE Your patient decides to proceed with an abdominoperineal resection. Q: What are the essential elements of this procedure?