Anastrozole compared to tamoxifen as primary endocrine therapy for early operable primary breast cancer in the elderly

Abstract

11025 Background: The optimal management of operable primary breast cancer in elderly is controversial. A high proportion of elderly patients refuse or are unfit for surgery. However the majority have oestrogen receptor positive (ER+) cancer and respond extremely well to endocrine therapy. The use of tamoxifen as primary therapy is well established but its efficacy has not been compared with the newer aromatase inhibitors in this setting. We present the clinical data of the use of anastrozole when compared with tamoxifen in elderly patients as primary therapy for operable breast cancer. Methods: During a period of 2 years, elderly patients with ER+ operable breast cancer (<5cm), who either refused or were unfit for surgery, were given primary endocrine therapy. Tamoxifen was given by default but anastrozole was used when there were contraindications (eg thromboembolic and gynaecological risks). All had disease assessable to UICC criteria and were followed up in a dedicated clinic. Only patients who had treatment for =6 months (except for those who progressed prior) were included for analysis. Results: A total of 93 patients fulfilled the criteria for analysis thus far and the results are summarised as follows: 58 were given anastrozole and 35 with tamoxifen. At a median follow-up of 14.8 months (6 to 57), 8 patients have progressed. The results are summarised as follows: CR = complete response PR= partial response SD = stable disease Treatment was well tolerated in both groups and no patients withdrew due to side effects. Conclusions: The use of primary endocrine therapy in ER+ operable breast cancer in the elderly is highly effective. In this observational non randomised study there was no difference in efficacy detected between tamoxifen and anastrozole at this time, as seen in adjuvant trials. This may be due to the fact that majority of ER+ cancer in the elderly are highly ER rich as shown by high semi-quantitative scoring of immunhistological assays, making the superiority of the aromatase inhibitors less apparent. [Table: see text] No significant financial relationships to disclose.