A Randomised Comparison of Anastrozole Commenced Before and Continued During Adjuvant Radiotherapy for Breast Cancer Versus Anastrozole and Subsequent Anti-oestrogen Therapy Delayed Until After Radiotherapy.
Adjuvant radiotherapy is well established as the primary modality to enhance local control
in breast cancer. The use of adjuvant hormone therapy such as tamoxifen has shown to
improve local control to a relatively minor amount on its own and does enhance local control
of adjuvant radiotherapy. There is, however, conflicting invitro and clinical data
regarding the effects or different sequences on tamoxifen and radiotherapy in terms of both
local control and enhancement of radiotherapy toxicities.
Aromatase inhibitors such as anastrozole are establishing themselves as a class of drug
superior to tamoxifen for the control of estrogen dependent breast cancers and overall are
better tolerated with the exception of greater bone loss.
As the key question is whether the sequencing of the aromatase inhibitor anastrozole alters
local control by acting as an enhancer of the radiation breast cancer cell kill, it is
therefore the aim of this study to compare 3 months of anastrozole prior to radiotherapy
versus 3 months of anastrozole after radiotherapy with a specific objective of reducing the
baseline ratio of in-field radiotherapy failure from 6% to 3%.
Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Treatment
To determine if commencement of anastrozole prior to radiotherapy results in improved local control compared to anastrozole commenced after radiotherapy.
10 years post radiotherapy
Peter Graham, MBBS
Trans-Tasman Radiation Oncology Group (TROG)
Australia: Department of Health and Ageing Therapeutic Goods Administration