Cox model results for the sequential treatments (four-arm option) compared with letrozole monotherapy at median follow-up of 71 months. (a) Tamoxifen followed by letrozole versus letrozole monotherapy. (b) Letrozole followed by tamoxifen versus letrozole monotherapy. Both analyses were stratified for chemotherapy use. The size of the boxes is inversely proportional to the standard error of the hazard ratio. As specified in the protocol to account for multiple comparisons, 99% confidence intervals are shown. Results are shown for the diseasefree survival, overall survival, and time to distant recurrence endpoints. Interaction tests between treatment and nodal status are not statistically significant. CI, confidence interval; Let, letrozole; Nx, regional lymph nodes not examined; Tam, tamoxifen. Reprinted with permission from The New England Journal of Medicine . Copyright 2009, Massachusetts Medical Society.