Prevalence and management of HER2/neu-positive early breast cancer in a single institution following availability of adjuvant trastuzumab

AIM

To ascertain the prevalence of HER2/neu-positive early breast cancer (EBC), utilisation of adjuvant trastuzumab and incidence of cardiac toxicity in a community private hospital setting.

METHODS

Prospective data collected by breast oncologist and surgeons in all women diagnosed with EBC at the Mount Hospital (MH) were reviewed. Women with HER2/neu-positive disease diagnosed between 1 October 2006 and 31 March 2009 were included in this analysis.

RESULTS

In total, 1128 women with invasive EBC were seen in the 30-month period. All tumours underwent HER2/neu testing by immunohistochemistry, with 61% being evaluated by in situ hybridisation. Time to definitive HER2/neu result improved over time from median of 17 to 14 days. The prevalence of HER2 positivity (by in situ hybridisation) in this cohort was 12%. Uptake of trastuzumab-based treatment was 100% in those patients receiving their treatment at the MH, compared to 52% of the 25 patients treated elsewhere. Ninety-eight per cent of MH patients completed the planned 12 months of therapy, with one patient developing recurrent disease and two patients experiencing significant cardiac toxicity. Chemotherapy relative dose intensity was 98% in HER2/neu-positive and negative patients. At a median of 25 months follow up, actuarial disease-free and overall survival in the HER2/neu-positive cohort is 99% and 100% respectively.

CONCLUSION

In a community private hospital setting, adjuvant trastuzumab and chemotherapy was delivered optimally, in line with national and international guidelines. Early efficacy and safety results in a non-clinical trial setting underscore the significant benefits achieved with this targeted therapy in HER2/neu-positive EBC.

Updated cost-effectiveness analysis of trastuzumab for early breast cancer: a UK perspective considering duration of benefit, long-term toxicity and pattern of recurrence

BACKGROUND

Trastuzumab has significantly improved survival outcomes for women with Human Epidermal growth factor Receptor 2 (HER2)-positive early breast cancer. Trastuzumab was established as a cost-effective adjuvant treatment in 2006. We present an updated cost-effectiveness analysis from the UK perspective, which explores assumptions about the duration of benefit from treatment, pattern of metastatic recurrence and long-term cardiac toxicity.

OBJECTIVE

The objective of this study was to calculate, from the UK NHS perspective, expected costs (year 2008 values) and benefits over the lifetime of an average cohort of women with HER2-positive early breast cancer treated with or without 1 year of adjuvant trastuzumab sequentially after chemotherapy.

METHODS

A cost-utility analysis was performed using a discrete-state time-dependent semi-Markov model. Probabilistic sensitivity analysis was used to characterize uncertainty around expected outcomes. Value-of-information (VOI) analysis was used to identify areas of priority for further research.

RESULTS

The cost-effectiveness estimates were highly sensitive to the estimated duration of treatment benefit. Trastuzumab remained a cost-effective treatment strategy at a willingness-to-pay threshold of £30,000 per QALY provided the duration of benefit was more than 3.6 years from treatment initiation, assuming the hazard ratio for disease-free survival was 0.63. An increasing proportion of brain metastases with trastuzumab produced a small change towards worse cost effectiveness. Long-term cardiac toxicity needed to rise to high levels to affect overall life expectancy and cost effectiveness. VOI analysis placed highest value on research into the duration of treatment benefit. The relationships between progression-free survival and overall survival and the costs of cancer recurrence were also important.

CONCLUSION

The cost effectiveness of adjuvant trastuzumab remains uncertain and dependent on assumptions regarding its clinical effect. Uncertainty around cost effectiveness could be reduced by further research into the duration of treatment effect, particularly in subgroups where this may be shorter. Long-term follow-up is warranted and methods to accurately measure duration of treatment effect and late toxicities should be developed for future adjuvant drug studies.