Heterogeneity between core needle biopsy and primary tumor tissue in early breast cancer patients: comparison of intrinsic subtypes after different treatment regimes

Background All initial therapeutic decisions in early breast cancer are commonly based on the expression profiles of estrogen (ER), progesterone (PR) and the human epidermal growth factor 2 (HER2) receptors. Only little data is known about receptor changes after upfront therapy. Here, we compared receptor expression profiles between core needle biopsy (CNB) tissue and primary tumor tissue after different treatment regimes.

Methods In a German single center study, we retrospectively analyzed 248 breast cancer patients during primary treatment regime between 2014 and 2020. Patients had either neoadjuvant chemotherapy, neoadjuvant endocrine therapy or no upfront therapy. Tumor material was obtained by core needle biopsy (CNB) at primary diagnosis and during primary oncological surgery. Analysis of histological subtype, grading, Ki67 index and expression profiling of ER, PR, HER2, was performed using formalin-fixed, paraffin-embedded (FFPE) specimens.

Results In the primary analysis 84 (39%) patients had neoadjuvant chemotherapy, 48 (23%) patients had neoadjuvant endocrine therapy and 81 (38%) patients had no upfront therapy. Overall, 77 (36%) patients had an intrinsic subtype change between CNB and definitive surgical treatment, 139 (64 %) patients had no subtype change. There were 44 (52%) changes after neoadjuvant chemotherapy, 17 (35%) changes after neoadjuvant endocrine therapy and 16 (20%) subtype changes after no upfront therapy (p<0.0001 for the effect of neoadjuvant chemotherapy).

Conclusions Our results imply the high frequency of intrinsic subtype changes after neoadjuvant therapy. Subtype changes should be taken into account for an optimal and individual treatment.

Publication History

Article published online:
21 June 2022