An assessment of extensive intraductal component as a risk factor for local recurrence after breast-conserving therapy.

The influence of extensive intraductal component (EIC) on local recurrence risk was studied for 496 patients with stage I-II infiltrating ductal cancers treated by conservative surgery and irradiation. EIC was diagnosed in 65 of 231 (28%) premenopausal and 41 of 265 (15.5%) post-menopausal patients. Local recurrence risk was markedly increased in EIC+ patients (5-year actuarial risk 18% versus 8% without EIC, P less than 0.001), but this effect appeared limited to premenopausal patients. Local recurrence risk increased with increasing degree of EIC. EIC with more than 50% intraductal carcinoma was more prevalent in patients younger than 40, perhaps accounting to some degree for the higher local recurrence rates observed in younger patients. The presence of EIC had no influence on overall survival, on median time to local recurrence, or on short-term survival after local failure. The usefulness of EIC as a risk factor for local recurrence is discussed.