PR73 ELECTROCHEMOTHERAPY: AN EFFECTIVE TREATMENT FOR INTRACTABLE CUTANOUS LESIONS SECONDARY TO BREAST CANCER

s / The Breast 22 S3 (2013) S19–S63 S45 19 (range 1-58), respectively. One hundred twenty five patients (75%) were positive for estrogen receptor. The incidence of SRE after bone metastasis were 10% in pathological fracture, 2% in spinal compression, 3% in surgery for bone lesion, 16% in radiation therapy and 1% in hypercalcemia. The one year cumulative incidence of SRE was 13.6% (95% confidence interval 7.7-19.5) and the two year cumulative incidence was 19.0% (95% confidence interval 12.1-26.0). Six patients (4.1%) had osteonecrosis of the jaw after the second year of ZOL administration, which was the only reason to discontinue ZOL treatment. The median overall survival after bone metastasis was 54.3 months (range 25-106). The median time to the first SRE was 48.5 months for higher Ki67 (≥20%) group versus 63.1 months for lower Ki67 (<20%) group (p=0.04). Conclusions: ZOL can provide safely long-term treatment for breast cancer patients with bone metastasis. Most SRE occurs in the first year; however, osteonecrosis of the jaw occurs after the second year.