Bilateral breast cancer. Clinical and histologic characteristics

Introduction. The occurrence of bilateral tumors is reported to be between 5 and 15% of women with breast cancer. This is a descriptive study of bilateral cancer of the breast. Material and methods. Retrospective review of all bilateral breast cancer treated between 1992 and 1997. We examine the clinical and histologic characteristics of bilateral tumors and similarities or differences between cancers that occur synchronously and metachronously. Results. Of the 1443 patients with cancer of the breast, 60 (4.2%) had bilateral cancers. Thirty nine tumors are synchronous (65%) and 21 metachronous (35%). The mean age at diagnosis of first cancer is 11 years younger in metachronous. Patients with family history of breast cancer were 35.9% in metachronous and 19% in synchronous. The interval between metachronous tumors was 80 months. There is no histologic differences between synchronous and metachronous cancers. Supervivence is best in metachronous. Conclusions. The risk of bilateral cancer is greatest in women whose first cancer develops in younger ages, and is higher in patients with a family history of breast cancer. An indefinite, meticulous follow-up is necessary to detect preclinical second cancers.