Clinical course of 771 patients with bilateral breast cancer: Characteristics associated with overall and recurrence-free survival

Purpose: Despite numerous retrospective and case-control studies, risk factors related to overall survival (OS) and recurrence-free survival (RFS) in bilateral breast cancer are still being defined. The aim of our study was to describe tumor properties, patient characteristics, and method of cancer detection for a large cohort of patients with bilateral breast cancer and to assess the associations of these factors with OS and RFS. Patients and Methods: A retrospective chart review was conducted at the University of Texas M. D. Anderson Cancer Center. Among patients with bilateral breast cancer, we compared primary versus contralateral tumors and synchronous versus metachronous cancers. Patient and second tumor characteristics were evaluated for an association with OS and RFS, as measured from diagnosis of the second tumor. Results: Of 11,234 patients with primary breast cancer seen for an initial visit between July 1, 1997, and December 31, 2004, 771 patients (6.9%) were diagnosed with bilateral breast cancer. The 5-year OS rates based on stage of the second tumor were 87.7%, 87.7%, 69.6%, 45.1%, and 23.8% for stages 0, 1, 11, 111, and IV, respectively (P < .0001). The 5-year OS rates for second tumor detection via mammogram/prophylactic mastectomy, physical examination, and self-examination were 81.6%, 70.9%, and 65.3%, respectively (P = .01). In addition, lymphovascular invasion, nuclear grade, hormonal receptor status, and histology were significantly associated with OS and RFS (P < .05). In a multivariable analysis, clinical stage and lymphovascular invasion remained significantly associated with OS (P < .05). Conclusion: This study represents the largest sing le-institution review of bilateral breast cancer. Numerous second tumor characteristics were associated with survival. The results emphasize the importance of earlier detection and improved staging for contralateral breast cancer.