Comparison of clinicopathological characteristics and prognoses between bilateral and unilateral breast cancer
BACKGROUND Although breast-conserving surgery followed by definitive irradiation is an established treatment for patients with early breast cancer, the role of breast-conserving therapy (BCT) for patients with bilateral breast cancer has not been well studied and the radiation therapy technique is still under investigation. We examined the feasibility of breast-conserving therapy for bilateral breast cancer and present here our radiation therapy technique with CT simulator. METHODS Between July 1990 and December 1998, we treated 17 patients with bilateral breast cancer who underwent bilateral breast-conserving surgery followed by definitive irradiation. Seven patients had synchronous bilateral breast cancer and ten had metachronous bilateral breast cancer. Radiation therapy consisted of 50 Gy to the bilateral whole breast in all patients but one. A CT simulator was used to plan a tangential radiation field to the breast in all patients. Boost irradiation of 10 Gy was administered to 8 tumors with close or positive margins. RESULTS With a median follow-up periods of 95 months from each operation, no patients showed loco-regional recurrence on either side, and none suffered distant metastasis. Furthermore no serious late adverse effects were observed. CONCLUSION This study demonstrated that BCT is feasible for bilateral breast cancer and the CT simulator is useful for determining the radiation field, especially when lesions are metachronous.