Audit of Grade 3 Breast Cancer in New Zealand Women
Breast cancer is the most common cancer in New Zealand women, accounting for approximately 3000 new registrations per year, affecting one in nine women and resulting in more than 600 deaths annually. The survival rate for breast cancer is dependent on multiple factors. These can include patient factors, tumour biology and resource-related factors such as access to health interventions. This study analysed data of selected prognostic factors of grade 3 tumours over a 5-year period from 1st January 2011 to 31st December 2015 from four Breast Cancer Registries (Auckland, Waikato, Christchurch, and Wellington). The study of 2667 women found that subjects in the older age group of >70 years were at increased risk of five-year mortality. Of the ethnicity groups, the Pacific Islander group were at increased risk, whereas the Māori group were at decreased risk. Histology type showed no statistically significant difference, whereas the molecular subtypes HER2 enriched and TNBC subjects were at increased risk. The study also showed that NZ Europeans presented the largest proportion of HER2 enriched and TNBC and the subjects from these two molecular subtypes were at increased risk of five-year mortality. In addition, analysis of the hormonal receptors showed that ER-negative, PR positive group were at increased risk and in contrast, the ER/PR positive group were at decreased risk. Subjects from stages II, IV and X were at increased risk, however, subjects from stage III were approaching significance. From the analysis, it can be noted that the survival rates for Grade 3 breast cancer vary across the selected prognostic factors and therefore it can be summarised that the survival of this disease is dependent on multiple factors. These factors can include patient factors, tumour biology and resource-related such as access to health interventions. Grade 3 is heterogeneous cancer and this study has shown that despite being high grade, not every patient has a poor outcome. Therefore, survival has to be combined with other factors such as biological and potentially socioeconomic factors associated with this disease. The results of this study make an initial contribution to the understanding of high-grade malignancy. The selected prognostic factors were used primarily as a preliminary study into the overall survival of this disease. The inclusion of other prognostic factors would potentiate further studies into this aggressive cancer. Such studies should be supported in order to gain better understanding and establishment of measures for the prediction of survival with grade 3 breast cancer in New Zealand women.