Giving patients a choice improves quality of life: a multi-centre, investigator-blind, randomised, crossover study comparing letrozole with anastrozole.

ABSTRACT

AIMS: Although the third-generation aromatase inhibitors are generally well tolerated, side-effects still occur in up to 40% of women. As more women are taking these drugs for longer, the issue as to which version is better tolerated is now a significant patient concern. This study aimed to assess whether tolerance for either letrozole or anastrozole can differ for each individual in terms of early quality of life (QoL), whether patients welcome being given a preference and whether this correlated with formal toxicity scoring. MATERIALS AND METHODS: A single-blind, crossover trial, with 72 women with breast cancer who had experienced tamoxifen failure. Randomised to either letrozole 2.5 mg or anastrozole 1 mg, for 4 weeks, 1 week off, then crossover for 4 weeks. RESULTS: Patients were confidently able to choose which drug suited them best (letrozole 68%, anastrozole 32%; P < 0.01). Fewer patients, when taking letrozole, experienced adverse events than when taking anastrozole (43% vs 65%; P = 0.0028). QoL was better when patients were taking letrozole than when they took anastrozole (P = 0.02). CONCLUSIONS: As toxicity and QoL strongly correlated with patient preference for either drug, albeit with a tendency towards letrozole, this suggests that patient preference is now a legitimate and useful end point for future crossover studies. In routine practice, women would warmly welcome extra involvement in the decision-making process via a crossover manoeuvre if side-effects develop, whichever aromatase inhibitor is prescribed initially.