Correlation between diagnostic core needle biopsies (CNB) and excisional biopsies (EB) in early breast cancer (EBC): a retrospective cohort analysis

Objektives A single-center, retrospective analysis evaluating the concordance of the molecular subtype, HR, HER2 status and Ki67 based on CNB and EB in primary EBC with and without primary systemic therapy (PST).

Materials and methods The analysis was performed in two cohorts: 1,002 EBCs with upfront surgery (C1) and 187 residual tumors (C2) after primary systemic therapy (PST).

Results Discrepancies of the molecular subtypes in C1 were 18.2 % for luminal A, 33.0 % for luminal B HER2-, 27.8 % for luminal B HER2+, 19.3 % for HER2 enriched und 10.1 % for basal like tumors, whereas in C2, were 31.5 % for luminal A, 49.1 % for luminal B HER2-, 39.0 % for luminal B HER2+, 23.1 % for HER2 enriched und 9.0 % for basal like tumors. Regarding ER, PR, HER2 status and Ki67 we identified the following discrepancies: 2.0 %, 10.0 %, 6.0 % and 20.3 % in C1 and 8.3 %, 27.1 %, 11.4 %, 52.1 % in C2. Present experimental data are suggesting that these treatment related changes are transient in nature, not qualifying for a change in post neoadjuvant treatment.

Conclusion Although the comparison between CNB and EB in C1 displays an acceptable concordance of prognostic factors, in C2 we identified a large variability, especially in luminal B EBCs. Fixational and observational issues, as well as heterogeneity of breast cancer might be the leading causes of these discrepancies. PST might modulate prognostic factors, especially PR and Ki67, and thus, the molecular subtype. The unmet clinical need remains if PST identifies a cellular selection for a different post-neoadjuvant treatment approach.

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Publication History

Article published online:
01 June 2021