Abstract P3-07-02: Developing a robust multidimensional molecular, pathological and radiological prognostic index (MPRPI) to evaluate the response to neoadjuvant chemotherapy (NACT) and predict clinical outcome of breast cancer (BC)

Background: Recently neoadjuvant chemotherapy (NACT) is regarded as a potential standard approach whenever chemotherapy is indicated in principle and is considered as the preferred treatment approach for stage II/III triple-negative and HER2-positive BC. However, there is an urgent need to develop a more sensitive and robust test that can assess the response for NACT and guide the optimum adjuvant therapy. Aim: Our aim is to identify molecular, radiological and histopathologic criteria that could grade response to NACT and to develop a robust prognostic index that accurately predict clinical outcome of the subsequent adjuvant therapy. Method: Comprehensive histopathological and radiological assessment of consecutive series of 850 BC [T2-4, N0-3, M0] have been centrally carried out at the Nottingham University Hospital (NUH). Furthermore, the immunohistochemistry expression of Ki67 and SPAG5 proliferation biomarkers and the histological evaluation of tumour infiltration lymphocytes (TILs) had been examined in all patients while both volumetric and texture changes detected by magnetic resonance imaging (MRI) were available for 400 cases. Oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) were assessed according to the most recent American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) guidelines. The results were validated in an external cohort of 250 cases. The patient’s characteristics and treatment options are the same between the centres: (68%) has received anthracycline plus Taxane (AC+T) NACT and 32% of patients have received NACT Anthracycline only (AC). Neoadjuvant HER2 targeting agents (Trastuzumab) or (Trastuzumab + Petruzumab) had been prescribed to 16% of patients in addition to AC+T followed by adjuvant Trastuzumab (total=18 cycles). All pre-NACT ER+ patients were given at least 5 year of adjuvant endocrine therapy. The primary end point was disease free survival (DFS). The median follow up was 72 months. Results: Using multivariate Cox proportional hazards models with backward stepwise exclusion for DFS, we found the presence of TILs [(HR (95% CI): 0.68 (0.48-0.94; P=0.022], high SPAG5 expression in post-surgical tumour tissue [(HR (95% CI): 2.58 (1.19-5.63), p=0.017)], the reduction in the primary tumour volume measured by MRI (>30%) [(HR(95% CI): 0.38 (0.16-0.89), p=0.026)], presence of Lymphovascular invasion [(HR(95% CI): 2.92 (1.33-6.40), p=0.008)], presence of chemotherapy induced fibrosis [(HR(95% CI): 0.41 (0.19-0.91), p=0.029)] and the high histological grade [(HR(95% CI): 2.62 (1.19-5.74), p=0.016)] showed statistical significant association with DFS. A prognostic index was calculated using the aforementioned factors after adjusting for both NACT and adjuvant therapy. The receiver-operating characteristic (ROC) curves indicated that this model is a good prognostic test [AUC = 0.854 (95% CI) = 0.777-.0.931; p= 0.00000001] and it outperformed residual cancer burden (RCB score) [AUC = 0. 711 (95% CI) = 0.612-.0.810; P= 0.0003]; and other NACT response grading systems including Miller-Payne system, Clinical-Pathologic Scoring System (CPS) and CPS-ER histological grade (CPS-EG) systems. Conclusion: A prognostic test with high sensitivity and specificity for assessing response to Neo-ACT has been developed and applying this test could guide the choice of the optimal adjuvant therapy.

Citation Format: Tarek M. a. Abdel-Fatah, Xin Chen, Ruizhe Li, Elisabetta Giannotti, Dorothee Auer, Jennifer Walker, Jun Lim, A. Graham Pockley, Graham Ball, Emad Rakhah, Ian Ellis, Arlene Chan, Stephen Chan. Developing a robust multidimensional molecular, pathological and radiological prognostic index (MPRPI) to evaluate the response to neoadjuvant chemotherapy (NACT) and predict clinical outcome of breast cancer (BC) [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-07-02.

Abstract P5-06-06: Clinically significant changes of receptors status (ER, PR and HER2) after receiving neoadjuvant chemotherapy (NACT) in breast cancer (BC) predicts the prognosis and guides the choice of the optimal adjuvant therapy (AT): Retesting of the receptor status should be mandatory

Background: NACT is a standard option for BC (T2-4, N0-3, M0) and certain BC phenotypes. The choice of AT based on the pre-NACT biomarkers status may not be optimum for individual patient because dynamic phenotypic changes induced by NACT may alter the response to treatment. Aim: The aim of this study is to determine the incidence of changes in the receptor status (ER, PR and HER2) and other proliferation biomarkers (Ki67 and SPAG5) before and after NACT and to assess the clinical significance of such changes. Methods Immunohistochemistry staining of ER, PR, HER2, Ki67 and SPAG5 in pre and post NACT tumors tissues from a consecutive series of 850 of BC (T2-4, N0-3, M0) treated at the Nottingham University Hospital (NUH) from 2000 to 2018, have been centrally evaluated according to ASCO guidelines. All cases with conversion in HER2 status had also been retested by HER2-FISH. The results were validated in an external cohort of 250 cases. Treatment options and patients characteristics are the same between the centres: (68%) received anthracycline plus Taxane (AC+T) NACT and 32% of patients have received NACT Anthracycline only (AC). Neoadjuvant HER2 targeting agents (Trastuzumab) or (Trastuzumab + Petruzumab) had been prescribed to 16% of patients in addition to AC+T followed by adjuvant Trastuzumab (total=18 cycles). All pre-NACT ER+ patients were given at least 5 year of adjuvant endocrine therapy (ET). In 2013 NUH started a prospective audit of retesting of receptor status in all post NACT surgical tumour samples. The results of the tests were presented to the weekly tumour board meeting and any change in the receptor status (ER and HER2) from negative (in the pre NACT core biopsies) to positive (in the post NACT surgical specimen) being considered for additional AT (ET for ER+ and Trastuzumab for HER2+ cases).The primary end points for this study are the % changes of biomarker changes and the disease free survival (DFS). The median follow up was 72 months. Results In pre NACT core biopsies 32% and 68% were HER2+ and HER2-; respectively. Twelve percent (12%) of the pre NACT HER2- tumours had a conversion to HER2+ in the post NACT surgical specimens. In this group of patients who subsequently received adjuvant Trastuzumab, 95% 3-year DFS was reported; which was similar to those patients who achieved pCR (3-year DFS; 90%) and was superior to cases which remained HER- in post NACT specimens (3-year DFS; 41%); (p<0.0001). Furthermore, similar group of patients with pre NACT HER- tumour before the 2013 audit, who did not receive Trastuzumab for the change to post NACT HER2+ receptors, has inferior 3-year DFS to those received adjuvant Trastuzumab based on the conversion (HR (95% CI)= 7.40 (1.04-52.86); p=0.046). In pre NACT HER2+ BC, 20% of cases had been converted into HER2- in the post NACT surgical specimens. These patients had better 3y-DFS (94%) compared to those who remained HER2+ in post NACT specimens (3y-DFS=70%; HR (95% CI)= 0.86 (0.77-0.97); p=0.01). Furthermore those patients who received neoadjuvant HER2 targeting therapy had statistically higher incidence of post HER2- conversion (p=0.005) and lower level of post NACT proliferation markers (Ki67 and SPAG5); p=0.01. In pre NACT ER+/PR+ patients, those who has converted into ER+/PR- in post NACT specimens had shorter 5-year DFS (40%) in spite of receiving ET, compared to those who remained ER+/PR+ in post NACT specimen [5-DFS= 72%]; HR (95% CI)= 1.98 (1.18-3.31); p=0.009). Conclusion: To our knowledge, this is the first report, which showed the significant clinical benefit of adjuvant therapy, based on the re-testing of the standard receptors status.

Citation Format: Tarek M. a. Abdel-Fatah, Rebekah Webb, Jennifer Walker, Jun Lim, A. Graham Pockley, Graham Ball, Matthew Griffiths, Ian Ellis, Emad Rakhah, Zsolt Hodi, Andrew Lee, Arlene Chan, Stephen Chan. Clinically significant changes of receptors status (ER, PR and HER2) after receiving neoadjuvant chemotherapy (NACT) in breast cancer (BC) predicts the prognosis and guides the choice of the optimal adjuvant therapy (AT): Retesting of the receptor status should be mandatory [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-06-06.

Evidence that neoadjuvant anthracycline based combination chemotherapy (NACT) in breast cancer (BC) induces phenotypical changes which guides the optimal adjuvant therapy

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Background: We hereby evaluated the histopathological and radiological alterations of tumor characteristics after receiving NACT and the clinical significance of the changes of adjuvant therapy based on these findings. Methods: A pathological assessment of tumor features including ER, PR, HER2 and proliferation markers (Ki67 and SPAG5) status in pre and post NACT tumors tissue have been centrally evaluated in two cohorts [Nottingham University Hospital (NUH; n=850) and Australian cohort (n=250 patients)]. Since 2013 any change in the ER and HER2 status from negative (-) [in the pre NACT biopsies] to positive (+) [in the post NACT surgical specimens] received additional adjuvant therapy (Endocrine therapy (ET) for ER+ and Trastuzumab for HER2+ cases) in NUH. MRI volumetric and texture changes have been assessed in 400 cases. The primary end point was disease free survival (DFS; median follow-up = 62 months). Results: 10% of pre NACT HER2- cases had been converted to post NACT HER2+ and those cases who subsequently received adjuvant Trastuzumab had achieved 92% 5-year DFS compared to those who remained HER- in post NACT specimens (58% 5-year DFS); (HR (95% CI)= 0.25 (0.08-0.80); p=0.016). While 13% of pre NACT HER2+ tumors were converted into HER2- in post NACT surgical specimens and had similar 5-year DFS to those who remained post NACT HER2+ (5-year DFS= 94% vs., 87%; p=0.613). Loss of PR in the residual disease of pre NACT ER+ BC was associated with shorter 5-year DFS after ET compared to those who remained post NACT PR+ (HR (95% CI)=2.1 (1.25-3.46); p=0.005). After NACT, 40% of pre NACT SPAG5+ cases were converted into post NACT SPAG5- and these patients had prolonged DFS compared to those who remained SPAG5+ in post NACT specimens (27%) [5-year DFS=84% vs 49%; (HR (95% CI)= 3.8 (2.1-6.9); p<0.0001). A prognostic model has been generated including factors in table (AUC = 0.854 (95% CI) = 0.777-.0.931; p= 0.00000001]. Conclusions: We hereby showed evidences a change of treatment strategy based on the changes in the tumor post NACT phenotype gives the optimal choice of treatment eg., the introduction of HER2 targeting therapy for the conversion of HER2– to HER2+ phenotype after NACT improved DFS. Multivariate Cox regression model for 5-year DFS. [Table: see text]