A Mater Research study1 has identified a method to identify best treatment options for oestrogen receptor positive breast cancer patients following surgery and also to better predict prognosis.
The study, published in the Journal of Clinical Pathology, found that aromatase inhibitors may be a more effective treatment for patients with oestrogen receptor positive (ER+) HER2 breast cancer than using tamoxifen. It also found that testing lymph node metastases for progesterone receptor (PR) was more accurate at predicting prognosis than testing the primary tumour.
Lead author and Betty McGrath Fellowship awardee Dr Cameron Snell said that following breast cancer removal, analysis of the tumour provided the biggest influence on how a patient is treated.
“Tumour characterisation allows oncologists to determine if a patient is likely to respond to a particular therapy or not,” Dr Snell said.
“Most patients with breast cancer are treated with endocrine therapy but not all patients respond to this treatment.
“The tools we have at the moment are quite crude so we are looking at better ways to predict a patient’s response to endocrine treatment and to identify patients who may relapse.
“We found that for patients with ER+, HER2 breast cancer who had no PR expression in the lymph node metastases, that aromatase inhibitors may be a more effective endocrine treatment than tamoxifen.”
“We are really moving towards tailoring patient treatments to their individual tumour to provide the most effective treatment for their cancer, rather than a one size fits all philosophy.”
The study retrospectively analysed PR expression in 229 patients with oestrogen receptor (ER) and HER2 negative breast cancer to determine if the metastases could provide more accurate prognostic information than evaluating the primary tumour.
“Performing progesterone receptor (PR) immunohistochemistry in lymph node metastases provides more accurate prognostic information in patients with node-positive, oestrogen receptor positive (ER+) HER2 breast cancer,” Dr Snell said.
“Most significantly, we found that increasing numbers of positive nodes, PR negativity in the lymph node metastasis and taking prescribed endocrine therapy are independent predictive factors of relapse.”
“We are working to understand who will respond to which drugs at the earliest possible stage and ultimately the earlier we can implement effective treatment, the more successful we will be in curing breast cancer.”
Dr Snell is starting work on a new project to develop a new test to identify sensitivity to Aromatase Inhibitors which will enable oncologists to further refine their ability to identify best treatment options for breast cancer patients.
A partnership with QUT is also in discussion to establish a Mater breast cancer biobank to collect research material from patients to be used for further studies into breast cancer.
Dr Snell said the Betty McGrath Fellowship had been instrumental in being able to undertake his research.
“The Fellowship enables clinicians to dedicate time to research activities and without this funding my research would not be possible,” Dr Snell said.
The Betty McGrath Fellowship Scheme is a joint initiative of Mater Health and Mater Research and is funded by Mater Foundation. It is designed as an additional avenue to improve evidence-based clinical practice at Mater.
The Betty McGrath Fellowships were created as an expression of appreciation to Betty McGrath OAM who was a Founding Member of Mater Foundation in the 1980s. Betty served as a Board Member of Mater Foundation until 2014 by which time she had accumulated 25 years of outstanding service.
1Snell CE, Gough M, Middleton K, et al. Absent progesterone receptor expression in the lymph node metastases of ER-positive, HER2-negative breast cancer is associated with relapse on tamoxifen. Journal of Clinical Pathology Published Online First: 17 April 2017. doi: 10.1136/jclinpath-2016-204304
http://jcp.bmj.com/content/early/2017/04/17/jclinpath-2016-204304