Variables correlated with the risk of lymph node metastasis in early rectal cancer.

To ascertain the risk of lymph node metastasis (LNM) from early rectal cancer, the authors retrospectively analyzed 154 patients with pT1 or pT2 rectal cancer treated by radical resection. Gross and microscopic pathologic characteristics of the primary tumor were examined as predictors of LNM. Comparisons were done by Fisher's test; significance was defined as a P value of less than 0.05. The incidence of LNM for T1 and T2 tumors was 3 of 26 (12%) and 28 of 128 (22%), respectively. LNM occurred significantly less often in well-differentiated cancers (0 of 12.0%). The incidence of LNM for T1/T2 tumors without lymphatic vessel invasion (LVI) or blood vessel invasion (BVI) (20 of 119, 17%) was significantly less than that for T1/T2 tumors with LVI or BVI (10 of 32, 31%). None of the T1 tumors without LVI or BVI had LNM. There was a trend toward decreased LNM for sessile nonulcerated tumors compared with nonpolypoid, exophytic, or ulcerated lesions (P = 0.06). Tumor size and colloid histologic characteristics were not significant predictive features for LNM. The data suggest that local excision alone is adequate for well-differentiated or moderately differentiated T1 rectal cancer in the absence of LVI or BVI and for well-differentiated T2 tumors. Radical resection or local excision combined with pelvic radiation therapy may be more appropriate for the remainder of early cancers.