European Multidisciplinary Cancer Congress (EMCC) 2011, 23-27 September, Stockholm

Frequency of biopsies for breast cancer tumours

Dr Linda Lindstrom – Karolinska Institutet, Stockholm, Sweden

 

Thank you. Good morning, my name is Linda Lindstrom and I’m a Postdoctoral Fellow at the Department of Oncology and Pathology at Karolinska Institutet, here in Stockholm. This morning I want to talk to you about the fact that clinically used breast cancer markers are unstable throughout tumour progression.

The clinical management of breast cancer relapse is often based on primary tumour characteristics such as oestrogen receptor, ER status, progesterone receptor, PR status, and human epidermal growth factor receptor 2, called HER2 status. As you know ER status and HER2 status predict treatment response, so in patients with ER positive tumours the tumours need oestrogen to grow and these patients generally receive anti-hormonal treatment while breast cancer tumours in HER2 positive patients make too much, they over-express the HER2 protein that promotes cell growth and drugs are also available here to target the HER2 protein.

Our aim was to assess each individual ERP or HER2 status, throughout tumour progression. Specifically we wanted to understand how the markers alter within the patient between primary tumour and first breast cancer relapse in addition to between several sites of relapse in the same patient. So our cohort is defined by female individuals diagnosed with a local or systemic relapse in the Stockholm healthcare region from January 1997 throughout December 31st 2007. The intra-patient marker statuses were manually collected from original pathology reports.

So to summarise our findings, here we see the ER status in primary tumour and first relapse site from the same patient. So in summary we had 459 breast cancer patients where we both had a primary tumour ER status and relapse ER status available. We could see that in the primary tumour 72% of the patients were ER positive while 28% were ER negative. For the ER positive tumours we could see that a little bit less than half of patients continued to be ER positive in the relapse while one in four patients lose ER receptor at relapse. For the ER negative patients we saw that one out of five patients continued to be ER negative stable also in the relapse setting while 80% actually gain oestrogen receptor status at relapse. In addition we also looked at several consecutive relapse sites from the same patient and at the first relapse a little bit more than half of the patients were ER positive while a little bit less than half were ER negative at first relapse. Out of the patients being oestrogen receptor positive, a little bit more than a third of the patients were stable ER positive all through the relapse setting and I want to mention that we had collected information from two up to six relapse sites from the same patient. In the oestrogen receptor positive patients at first relapse we also saw that 16% lost oestrogen receptor status during the relapse setting while for the ER negative patients we saw that a third continued to be ER negative all through their advanced disease, while 13% gain oestrogen receptor status during the disease progression.

So in a clinical setting the implication of oestrogen receptor instability is important because the loss of oestrogen receptor generally means resistance to hormonal therapy and these patients would benefit from a therapy change. In addition, an oestrogen receptor gain in the relapse setting would also introduce an additional choice of therapy that could, potentially in some patients, lead to tumour response and prolong survival in the metastatic setting. In conclusion, since therapy predicting markers are unstable through tumour progression, this dynamic brings forward the potential need of taking biopsies in a continuous manner, also in the advanced setting, to enable optimised treatment decisions for the patient.

Thank you very much.