Prediction of recurrence in incompletely excised basal cell carcinoma.

This 5-year prospective study evaluated histologic criteria as predictors of tumor recurrence for the individual with a "positive-margin" basal cell carcinoma. The results demonstrated that 93 percent of patients with greater than 75 percent of their tumor cords containing irregularities in in the peripheral palisade had tumor recurrence, while no patient with less than 25 percent of their tumor cords containing irregularities in the peripheral palisade developed a recurrence in 5 years of follow-up. After statistical analysis for the other histologic variables, the presence of greater than 75 percent irregularities in the peripheral palisade conferred a 39-fold increased risk of tumor recurrence, significant at the p much less than 0.001 level. For the patient in the intermediate group (25 to 75 percent irregularities in the peripheral palisade), the presence of a weak host response (absent to minimal infiltration of small lymphocytes) increased the risk of tumor recurrence fourfold, with this effect being significant at the p less than 0.05 level. The presence of tumor ulceration conferred a 2.8-fold increased risk for tumor recurrence, significant at the p less than 0.01 level, while the presence of squamous differentiation conferred no increased risk. This study may provide a valid basis for predicting tumor recurrence in the individual with a positive-margin basal cell carcinoma.