[Lani]

Time and time again at meetings I hear the researchers and oncologists say "we wish we had a biopsy of the metastasis to clarify what is going on"

Here is why:


Molecular changes in the primary breast cancer versus the relapsed/metastatic lesion from a large population-based database and tissue microarray series.
Sub-category:
Metastatic Breast Cancer
Category:
Breast Cancer--Metastatic Breast Cancer
Meeting:
2008 ASCO Annual Meeting



Abstract No:
1000
Citation:
J Clin Oncol 26: 2008 (May 20 suppl; abstr 1000)
Author(s):
R. MacFarlane, C. Speers, H. Masoudi, S. Chia
Abstract:
Background: Relapsed/metastatic breast cancers are presumed to have the same predictive factors as the initial primary tumour. As such, the majority of patients do not have additional biopsies performed at the time of relapse. Recent small studies have suggested that a significant proportion of relapsed lesions may have a change in the hormone receptor and/or HER2 receptor status from the original tumour. We sought to compare the hormonal and HER2 receptor status of relapsed/metastatic breast cancer tumours with those of the original tumour from a large population-based database and tissue microarray (TMA) cohort. Methods: Using the BCCA Breast Cancer Outcomes Unit Database from 1986-1992, patients with biopsy proven relapses were identified. These identified patients were linked to a current large TMA series (n=4,444) of primary breast cancers. Charts were reviewed, and available tissue blocks of the relapsed/metastatic cancer were requested and collected. An additional TMA was created of the relapsed/metastatic tumours. IHC was performed for ER (LabVision SP 1 antibody), PR (Ventana 1E2 antibody) and HER2 (LabVision SP 3 antibody) on both the primary and relapsed tumours. The pathologist was blinded to knowledge of the primary tumour receptor status. Results: 281 cases were linked between the BCOU database and the TMA series. Of the 281 cases, 184 tissue blocks were received, and 160 had adequate tumour for analyses. Of the 160 blocks, 115 (72%) had no changes in either the ER/ PR or HER2 status. Of the 45 (28%) tumours that did have changes in the receptor status, 11 (7%) were local recurrence, 34 (21%) were regional or distant relapses. Among the 34 regional/distant relapses 11 went from ER/PR(+) to ER/PR(-), 14 went from ER/PR(-) to ER/PR(+), 3 went from HER2(-) to HER2(+), and 6 went from HER2(+) to HER2(-). Conclusions: This is one of the largest known studies assessing for changes in molecular phenotype between the primary and relapsed breast cancer. A significant proportion (21%) of relapsed tumours had changes in either ER/PR or HER2 receptor status. This study suggests that biopsies of relapsed/metastatic breast cancers should be performed routinely.