Kemik Metastazı Olan Metastatik Meme Kanseri Hastalarında İntravenöz Zolendronik Asit Kullanımının Meme Dokusunda Mikrokalsifikasyon Oluşumu Üzerine Etkisi

Abstract

Breast cancer is the most common type of cancer diagnosed in women and the second leading cause of cancer-related deaths in the world. Distant metastases are detected in approximately 20% of patients, and bone metastases are detected in approximately 80% of distant metastatic patients. After studies showing the positive effects of bisphosphonate use on disease-free survival in bone metastatic disease, the use of bisphosphonates in these patients has become widespread. However, it has been shown that long-term use of bisphosphonates can cause pathological calcium deposits with its effects on calcium metabolism in the body. There are cases of dystrophic calcification thought to be caused by long-term use of bisphosphonates in the literature. In addition, studies have reported that the presence of microcalcifications in breast tissue is associated with an increased risk of breast cancer. In this study, we examined the effects of zolendronic acid use on calcifications in breast tissue in patients with bone metastatic breast cancer, based on the effects of bisphosphonates on calcium accumulation in the tissue and the relationship of microcalcifications with increased malignancy. 568 patients with the diagnosis of breast cancer who applied to the Medical Oncology Department of Hacettepe University Faculty of Medicine between 2016-2021, who had bone metastases and received zolendronic acid treatment, were examined. Mammography images of 219 patients, whose regular follow-ups could be reached, before and after zolendronic acid treatment were compared. It was determined that the patients evaluated in the study received 22.8 doses of zolendronate intermittently for an average of 3.6 years. A total of 72 patients had calcification during their follow-up. 55 of these were present before zolendronic acid treatment. In 17 patients, it was determined that calcifications occurred after zolendronic acid treatment was started. None of the 17 patients who developed calcification after the initiation of zolendronate therapy had calcifications of suspicious morphology that could be compatible with malignancy. It was found that after the initiation of zolendronate therapy in these patients, an average of 2.7 years passed until calcification developed, and the patients received an average of 19.9 doses of zolendronate at intervals until calcification developed. Three-quarters of the patients developed calcification three years after starting zolendronate therapy. With these findings, the direct effect of malignant calcification formation in breast tissue with the use of zolendronic acid could not be demonstrated. It was thought that the development of calcification in the breast tissue may be faster in the first years when zolendronic acid treatment was applied intensively in patients with bone metastatic breast cancer. However, considering that there are other factors that may affect the calcification process, a definite relationship could not be established between the use of zolendronate and the formation of calcification.