Use of trastuzumab in Australia and New Zealand: Results from the National Breast Cancer Audit

Background:  Trastuzumab increases disease-free and overall survival in HER-2-positive, early breast cancer. In 2007, the National Breast and Ovarian Cancer Centre recommended that patients with HER-2 positive cancers (node positive or node negative tumours >1 cm) be offered adjuvant trastuzumab with chemotherapy. The aim of this study was to evaluate recent trends in trastuzumab therapy in Australia and New Zealand. Methods:  Following data were obtained from the National Breast Cancer Audit for patients treated between 2006 and 2008: tumour size, number of cases recorded per surgeon per year, location of hospital, HER-2 receptor status, age, lymph node status, chemotherapy and trastuzumab treatment. Results:  Data were available from 23 290 patients. During the study period, the percentage of breast cancers tested for HER-2 rose from 77% to 91%. Patients over 70 had fewer HER-2 tests than their younger counterparts. Fourteen percent of tumours were HER-2 positive; the proportion treated with trastuzumab in 2006, 2007 and 2008 was 50%, 66% and 74%, respectively. Significantly more node-positive patients (77%) were given trastuzumab than node-negative patients (52%). All the patients prescribed trastuzumab also received chemotherapy. Patients under 70 years, patients treated in Australia and patients treated by higher caseload surgeons were more likely to be prescribed trastuzumab than those over 70, patients in New Zealand and patients treated by lower caseload surgeons. Conclusions:  Trastuzumab-prescribing trends conform to the published guidelines. However, older patients and those with HER-2 positive, node-negative tumours >1 cm may be undertreated in some cases.Robert Whitfield, James Kollias, Primali De Silva, Helen Zorbas and Guy Madder