Purpose: The aim of this study was to investigate the potential benefits of prolonged treatment with neoadjuvant letrozole.
Patients and methods: About 182 consecutive patients have been treated in Edinburgh with neoadjuvant letrozole for 3 months or longer and 63 patients have continued on letrozole beyond 3 months. Outcomes are reported.
Results: Of the 63 patients who continued on letrozole, 38 patients took letrozole for more than 1 year and 23 took letrozole for more than 24 months. The median reduction in clinical volume in the first 3 months in these 63 patients was 52%. Similar reductions in median clinical volume were seen between three to 6 months (50%), 6-12 months and 12-24 months (medians 37 and 33%, respectively). At 3 months 69.8% of the 182 patients had a partial or complete response. The response rate increased to 83.5% with prolonged letrozole treatment. Continuing letrozole beyond 3 months increased the number of women who initially required mastectomy or had locally advanced breast cancer who were subsequently suitable for breast conserving surgery from 60% (81/134) at 3 months to 72% (96/134). Thirty-three women remain on letrozole alone (man age at diagnosis 83 years) and at 3 years the median time to treatment failure has not been reached.
Conclusion: Continuing letrozole in responding patients beyond 3-4 months achieves further clinical reduction in tumour size. For elderly women with a short life expectancy letrozole alone may provide long-term disease control.