The impact of tumor size and histology on local control after breast-conserving therapy.

To investigate possible contraindications for breast-conserving therapy (BCT) a retrospective clinicopathological study was carried out in 585 patients treated conservatively in The Netherlands Cancer Institute from 1979 to 1984. The local recurrence rate in the breast was 2% at 6 years and was similar in stages I and II breast cancer. Invasive cancer with extensive ductal carcinoma in situ (DCIS) component appeared to be the only main prognostic factor when local failure in the breast was considered. A multivariate analysis revealed that tumor size, microscopically incomplete excision of the primary tumor and age did not have a significant influence on local control alone, when this was corrected for extensive DCIS. When breast and axillary recurrences were taken together, age and extensive DCIS component appeared to be two independent prognostic factors according to a multivariate analysis. Especially patients younger than 40 years with an extensive DCIS component had a higher locoregional recurrence rate.