NMS. Casos Clínicos

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Part II ♦ Specific Disorders

B

C Figure 8-28: (Continued) B: Diagram showing distinction of carcinoma in situ and invasive malignancy of the colon. (From Greenfield LJ, Mulholland MW, Oldham KT, et al, eds. Surgery: Scientific Principles and Practice , 2nd ed. Philadelphia: Lippincott Williams & Wilkins; 1997:1132.) C: Stage T1 rectal carcinoma on endorectal ultrasound. (From Wanebo HJ, ed. Surgery for Gastrointestinal Cancer . Philadelphia: Lippincott-Raven; 1997:174.) Several additional factors that influence practice mostly relate to the type of lesion. Lesions with large lateral components require a wider margin of resection. Thus, abdom- inoperineal resection is more likely for lesions larger than 5 cm (Fig. 8-29). Rectal cancers that involve the regional lymph nodes (stage III) or high-risk stage II tumors also require postoperative adjuvant chemotherapy that is similar to that used with colon cancer. Local recurrence of rectal carcinoma is a common mode of failure. Therefore, am- ple, clear margins are mandatory at the initial procedure. SAMPLE