Placing the radiation source inside the rectum (intraluminal radiation therapy) may result in a high cure rate in some cases, as with a well-differentiated tumor less than 3 to 4 cm (1 to 1¬Ω in.) above the sphincter , for example. This may preserve the sphincter.
Adjuvant Radiation Therapy Radiation therapy given after surgery may be more effective in rectal cancer than in colon cancer because of the increased tendency for tumors to grow back locally. Several trials of adjuvant radiation and chemotherapy after an abdominal perineal resection have suggested a decrease in the rate of local recurrence with a small increase in disease-free and overall survival.
Adjuvant Chemotherapy Stage I (Dukes' A and B1) tumors have a high cure rate with surgery alone and there is no need for adjuvant chemotherapy for these stages. But for more advanced tumors (Dukes' B2 and C), the use of chemotherapy alone has shown some improvement in survival. Combination therapy, using chemotherapy plus radiation, is better than either therapy alone and should be started within six weeks of surgery.
Combined Therapy Disease-free survival has recently been extended in patients with Dukes' B2 and C rectal cancer treated with both chemotherapy and radiation, compared with those treated with radiation therapy alone.
