Abstract P3-02-01: Impact of prognoses on the discrepancies in histological grade of breast cancer between core needle biopsy and surgical excision specimen

Purpose: The high reliability and utility of core needle biopsy (CNB) have been previously described. Histological grade in CNB is one of the main determinants of the need for neoadjuvant systemic therapy. Our aim in this study was to clarify the host and histopathological factors influencing the discrepancies in histological grade (HG) between CNB and surgically excision specimen (SES).

Methods: A total of 1342 operable invasive breast carcinoma biopsies were assessed and compared with surgical specimens in our hospital. Patients who required neoadjuvat chemotherapy were excluded. Histological grade (tubule formation, nuclear pleomorphism and mitotic index) was assessed between paired CNB and SET samples.

ER and PgR status were determined using immunohistochemistry(IHC). HER2 status was determined using IHC and scored from 0 to 3+. Fluorescence in-situ hybridization analysis was carried out in HER2 2+ cases. The cut off point for ER and PgR positivity was set at 1%.

Results: The clinicopathological characteristics of tumors showed in

Clinico-pathological characteristics of 1342 patients and tumors by discordance group between CNB and SES for histological grade  LL groupHH groupHL groupLLHgroupp valupTT1a31 (94%)0(0%)2(6%)0(0%)0.001 T1b162(92%)4(2%)1(1%)10(6%)  T1c421(79%)43(8%)14(3%)52(10%)  T2335(68%)63(13%)10(2%)82(17%)  T352(68%)8(10%)2(3%)15(19%)  T425(71%)4(11%)0(0%)6(17%) pNnegtive668(78%)73(9%)13(2%)101(12%)0.08 positive358(74%)49(10%)16(3%)64(13%) lynegative600(79%)6(4(8%)14(2%)85(11%)0.18 positive426(74%)58(10%)15(3%)80(14%) vnegative799(80%)81(5%)23(2%)98(10%)0.001 positive227(67%)41(12%)6(2%)67(20%) ER/PgRmegative82(33%)83(33%)13(5%)72(29%)0.001 positive944(86%)39(4%)16(1%)93(9%) HER2negative932(80%)86(7%)22(2%)121(10%)0.001 positive94(52%)36(20%)7(4%)44(24%) CNB;core needle biopsy, SES;surgical excision specimen, HH group (high grade in CNB/high grade in SES), LL group (low grade in CNB/low grade in SES), HL group (high grade in CNB/low grade in SES) and LH group (low grade in CNB/high grade in SES)

. The concordance rates of HG of luminal type, HER2 type luminal HER2 type and Triple negative type in CNB and SES were 91%, 64%, 73% and 66%, respectively (p>0.001). Factors of discrepancy were T size, vessel invasion and ER/HER2 status for HG. The discrepancy factors were assessed with univariate and multivariate analysis. The underestimate and overestimate rates of HG in CNB compared to SES were7.5% and 1.3% in ER(+)HER2(-) type, 32%, and 3.1% in HER2 type, 22% and 4.3% in ER(+) HER2(+) type and 29% and 5.5% in Triple negative type(TN), respectively. The concordance rates of tubule formation, nuclear pleomorphism and mitotic index in CNB and SES were 81%, 97% and 93% in luminal type, 85%, 66% and 33% in HER2 type, 77%, 87% and 83% in luminal HER2 type and 82%, 67% and 73% in TN type respectively.

Conclusions: Using the largest known dataset to date of paired samples from a single institution, we evaluated the accuracy of CNB and the discrepancy factors between CNB and SES in breast cancer patients.

We conclude that CNB for histological grade assessment in patients with HER2 positive or TN breast cancer before neoadjuvant treatment should be used with caution.

Citation Format: Nakamura R, Yamamoto N, Miyaki T, Teranaka R, Itami M. Impact of prognoses on the discrepancies in histological grade of breast cancer between core needle biopsy and surgical excision specimen [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-02-01.