We report the impact of selected clinicopathologic features on local failure and disease-free survival in 22 patients with localized, mobile, primary resectable rectal cancer treated with local excision and postoperative radiation therapy. Full thickness local excisions with negative margins were performed in 21 patients. One patient had a transanal snare excision of a T1 polyp. Postoperatively patients received 4500-4950 cGy (medial 4680 cGy) whole pelvis, and in 15 this was followed by a conedown of 360-1000 cGy (median 360 cGy). Two received 5-FU. Tumors were evaluated for size, gross appearance, distance from the ana verge, T stage, blood vessel invasion, lymphatic vessel invasion, and DNA content (ploidy, DNA index, and proliferation index). The median follow-up was 37 months (range 5-73). With increasing T stage there was a corresponding increase in local failure (T1: 0%, T2: 17%, and T3: 33%) and a decrease in disease-free survival (T1: 100%, T2: 67%, and T3: 50%). When accounting for the effect of T stage, tumors which were either BVI-or ulcerative were associated with an increase in local failure, and tumors which were < or = 3 cm, ulcerative, or nonaneuploid were associated with a decrease in disease-free survival. However, none of the differences reached statistical significance. Although other clinicopathologic features may have an impact, T stage remains the most reliable clinicopathologic feature by which to predict local failure and disease-free survival in patients with rectal cancer who undergo local excision and postoperative radiation therapy.