Is adjuvant trastuzumab a cost-effective therapy for HER-2/neu-positive T1bN0 breast cancer?

Background: In light of clinical uncertainty and the high acquisition costs of trastuzumab, we examined the value for money associated with concurrent or sequential trastuzumab in women with HER-2/neu-positive breast cancer with small node-negative tumours (T1bN0). Materials and methods: A probabilistic economic model was developed to estimate the likelihood of adjuvant trastuzumab meeting a $100 000 per quality-adjusted life year gained threshold over a range of 10-year recurrence risks by age. The primary analysis took an incremental approach, comparing trastuzumab plus chemotherapy with chemotherapy alone. A secondary analysis took an 'all-or-nothing' approach, comparing trastuzumab plus chemotherapy with neither treatment. Results: The primary analysis suggested that concurrent trastuzumab plus adjuvant chemotherapy was likely to meet the $100 000 threshold at recurrence risks of 29-35%. Sequential trastuzumab was less likely to meet such a threshold. The secondary analysis was more favourable for both trastuzumab strategies, but of limited relevance as clinical benefits were predominantly driven by chemotherapy without trastuzumab. Conclusions: Concurrent trastuzumab plus adjuvant chemotherapy appears to offer favourable value for money at the upper ranges of baseline recurrence risks reported to date, although more precise estimates of underlying risk are required to confirm the cost-effectiveness of adjuvant trastuzumab in T1bN0 breast cancer.