Received: 18 January 2017 Accepted: 11 June 2017 Published on: 30 August 2017
The use of trastuzumab in New Zealand women with breast
Ross Lawrenson Chunhuan Lao Ian Campbell Vernon Harvey
Charis Brown Sanjeewa Seneviratne Melissa Edwards Mark Elwood
University of Waikato, New Zealand
Ross Lawrenson,University of Waikato, Level
3 Hockinbuilding, Waikato Hospital, Hamilton
Aim: Trastuzumab was ﬁrst funded in New Zealand for use in HER2+ve stage I–III breast cancer in
2007. This observational study aims to ascertain the patterns of use of trastuzumab in women with
invasive HER2+ve breast cancer, and assess the effectiveness of adjuvant trastuzumab in women
with stage I–III HER2+ve breast cancer.
Methods: The Waikato and Auckland Breast Cancer Registries have clinical details of 12 372
women diagnosed with invasive breast cancer between June 2000 and May 2013. The proportion
of women with HER2+ve breast cancer treated with trastuzumab was examined by age, ethnic-
ity, stage and year of diagnosis. Differences in outcomes including the development of metastases
and death were assessed for women with stage I–III HER2+ve breast cancer treated with both
chemotherapy and trastuzumab, compared to women treated with chemotherapy alone.
Results: Among the 1587 HER2+ve breast cancer patients, 888 (56.0%) women received
trastuzumab. The probability of having trastuzumab decreased with higher age and comorbidity
score and increased with year of diagnosis, tumor size and cancer stage. M
aori and Paciﬁc women
were less likely to be treated with trastuzumab. After adjustment for potential confounding fac-
tors, the treatment with trastuzumab improved breast cancer-speciﬁc mortality (adjusted hazard
ratio 0.57, 95% CI: 0.35–0.93).
Conclusion: Overall, this observational study has shown a substantial improvement in survival for
women with HER2+ve stage I–III breast cancer, and much of this improvement can be attributed
to the introduction of trastuzumab. Changes in chemotherapy also appear to have led to improved
breast neoplasms, epidermal growth factor, mortality, survival, trastuzumab
In New Zealand, the presence of the biomarker human epidermal
growth factor receptor 2 (HER2) in women with breast cancer has
been commonly ascertained since 1998, and routinely since 2006.
It has been found to be present in approximately 15–20% of breast
presenting more commonly in breast cancers of younger
It is known that women who have HER2 positive (+ve) breast
cancer have a poorer prognosis compared to women with HER2 nega-
tive (–ve) disease.
Trastuzumab (Herceptin) is a targeted therapy for patients with
HER2+ve breast cancer. Randomized clinical trials have shown that
trastuzumab reduced breast cancer recurrence and mortality in
women with early-stage HER2+ve breast cancer after surgery.
study combining data from the National Surgical Adjuvant Breast and
Bowel Project (NSABP) B-31 and North Central Cancer Treatment
Group (NCCTG) N9831 clinical trials with a median follow-up time of
8 years demonstrated a hazard ratio of 0.63 (95% CI: 0.54–0.73) in
breast cancer-speciﬁc mortality and a hazard ratio of 0.60 (95% CI:
0.53–0.68) in all-cause mortality after adding 12 months trastuzumab
to chemotherapy for HER2+ve stage I–III breast cancer.
Trastuzumab was ﬁrst licensed by the US FDA (Federal Drug
Regulatory Authority) in 1998 for metastatic HER2+ve breast cancer
and was funded for this indication in New Zealand since 2002 by
2017 John Wiley & Sons Australia, Ltd Asia-Pac J Clin Oncol. 2018;14:e152–e160.wileyonlinelibrary.com/journal/ajco