Demographic and clinico-pathological characteristics of breast cancer patients with history of oral alendronate use.

Bisphosphonates are the most commonly used agents in the treatment of osteoporosis, and bisphosphonate therapy reduces the risk of skeletally related complications in patients with bone metastases due to malignancy. However, the effect of oral alendronate treatment on clinical and pathological properties of breast cancer has not been reported. Thus, we aimed to investigate retrospectively the demographic and clinico-pathological characteristics of new diagnosis of breast cancer patients with oral alendronate users for longer than 1 year, compared with non-users. Newly diagnosed breast cancer patients from 1998 to 2010 in our clinic were retrospectively analyzed. Patient's demographics, including survival data and tumor characteristics, were obtained from medical charts. Breast cancer patients who were taking oral alendronate more than 12 months at the time of breast cancer diagnosis were enrolled as an alendronate users (n=44), where the patients matched with the same age who were not taking oral alendronate were included as a control group (n=444). A total of 488 patients were included in this study. Forty-four patients received an oral alendronate treatment more than 1 year, and 444 patients were considered as non-users. Median age of both alendronate users and non-users was 57 (33-89). Lower incidence of histological grade III, T3-T4 tumor, and node positivity was seen in alendronate users but not statistically significant. A similar trend for lower incidence of triple negative and higher incidence ER (P=0.13), progesterone receptor (P=0.12), and HER2 positivity (P=0.21) was also seen in alendronate users but not statistically significant. Estimated median disease-free survival was 150 months in alendronate users where as 70 months in non-users (P=0.015). Five-year survival rate in alendronate users was 97.4%, whereas in non-users was 89.8% (P=0.13). The use of oral alendronate for longer than 1 year at the time of breast cancer diagnosis was associated with better clinico-pathological properties and significantly improved disease-free survival in breast cancer patients.