Measuring SUCCESS.

Evidence is mixed on adding bisphosphonates every 3-6 months during aromatase inhibition for early-stage breast cancer in order to reduce fracture risk and possibly even maximize disease-free survival. The downside is a long list of bisphosphonate side effects, including jaw osteonecrosis, that become more apparent in long term survivors. The phase 3 SUCCESS A trial, rather than taking an all or nothing approach, compared 2 years (4 mg q3 months) versus 5 years (the same then 4 mg q6 months for 3 more years) of zoledronate for early-stage breast cancer. No difference could be detected in disease outcomes, while adverses events were increased from 27% → 46% with 5 years of zoledronate. | Friedl, JAMA Oncol 2021