Abstract P1-02-14: A comparative analysis of clinical and pathologic characteristics of patients with HER2 positive breast cancer treated with neoadjuvant versus adjuvant anti-HER2 therapy: Analysis of 397 cases

Abstract

Abstract A comparative analysis of clinical and pathologic characteristics of HER2 positive breast cancer patients treated with adjuvant versus neoadjuvant antiHer2 therapy: an analysis of 397 cases. Introduction: Currently there are several anti-HER2 therapy options for patients with HER2 positive breast cancer. Surgery as an initial treatment is usually performed in patients with smaller, node negative tumors. Neoadjuvant therapy (NAT) is the treatment of choice for patients with higher stage disease. Detailed analysis of clinical and pathologic characteristics of patients who received adjuvant versus NAT anti-HER2 therapy has not been well elucidated. Objectives: A comparative analysis of clinical and pathologic findings including biomarker expression (ER, PR, HER2 and Ki67) was performed to determine if there were differences in tumor characteristics and clinical outcome in the two groups.Methods:We retrospectively analyzed data on HER2+ breast cancer patients treated with adjuvant and NAT anti-HER2 therapy from 2011 to 2017. Clinical and pathologic parameters including biomarker expression prior to the start of therapy were obtained from the electronic database after IRB approval. In the adjuvant group, patients were treated with initial surgery followed by anti-HER2 therapy plus chemotherapy. In the NAT group, anti-HER2 therapy plus chemotherapy was administered prior to definitive surgery. Types of anti-HER2 therapies and follow-up information were obtained from the electronic medical record. Results:We identified 258 (64.9%) patients who received NAT and 139 (35.0%) received adjuvant anti-HER2 therapy. Table 1.VariablesNeoadjuvant groupAdjuvant groupp-valueAgeBelow 40 years42 (16.2%)11(7.9%)0.02940 years and above Total216 (83.7%) 258128 (92.0%) 139Menopausal statusPremenopausalPostmenopausal Total113 (45.3%)136 (54.6%) 24935 (25.1%)104 (74.8%) 139<0.001Nodal status on biopsyNegativePositive Total31 (18.1%)140 (81.8%) 17117 (53.1%)15 (46.8%) 32<0.001Tumor size by imaging (cm)Mean + SD3.87+2.832.24+1.76<0.001Tumor grade123 Total5 (2%)78 (31.3%167 (66.8%) 2507 (5.3%)49 (37.6%)74 (56.9%) 1300.068HER2 by IHC0 and 1+ (FISH +)2+ (FISH+)3+ Total11 (4.2%)61 (23.8%)184 (71.8%) 2564 (3.5%)41 (36.6%)67 (59.8%) 1120.042HER2 FISH copy no.Mean +SD15.44 ± 8.2512.64 ± 6.470.007HER2 ratioMean SD6.35 ± 3.445.57 ± 3.560.046ER statusNegativePositive Total113 (43.9%)144 (56.0%) 25745 (35.1%)83 (64.8%) 1280.122Percent positive71.38 ± 33.3778.74 ± 29.040.042ER intensity1+2+3+ Total24 (16.9%)38 (26.7%)80 (56.3%) 1422 (2.6%)26 (34.2%)48 (63.1%) 760.001PR statusNegative Positive Total147 (57.1%)110 (42.8%) 25766 (51.9%)61 (48.0%) 1270.389Percent positive42.33 ± 34.5444.72 ± 32.890.645PR intensity1+2+3+ Total20 (18.5%)41 (37.9%)47 (43.5%) 10810 (17.5%)30 (52.6%)17 (29.8%) 570.012KI67 indexPercent positive49.44 ± 22.6638.56 ± 22.36<0.001Anti-HER2 therapyHerceptinHerceptin+ Perjeta Total72 (31.0)160 (68.9%) 23291 (89.2%)11 (10.7%) 102<0.001SurgeryTotal Partial BilateralModified radicalOther Total SurvivalAlive. Dead116 (44.95)75 (29.0%)25 (9.6%)38 (14.7%)04 (1.5%) 258 239 (92.6%) 19 (7.3%)55 (40.4%)56 (41.1%)18 (13.2%)5 (3.6%)02 (1.4%) 136 125 (89.9%) 14 (10.0%)0.002 0.458Conclusions:Patients who received NAT were significantly younger, premenopausal with more aggressive tumor biology (higher Ki67, HER2 expression). Recent advances in anti-HER2 therapy has improved the outcome of these patients despite having higher stage disease. Breast conserving surgery was higher in the adjuvant group since the tumors were smaller in size. There was no significant difference in overall survival when compared to the adjuvant group (p=0.458) Citation Format: Venetia Sarode, Tricia Rood, Yulun Liu, Yisheng Fang, Sunati Sahoo, Yan Peng, Helena Hwang, Marilyn Leitch, Barbara Haley. A comparative analysis of clinical and pathologic characteristics of patients with HER2 positive breast cancer treated with neoadjuvant versus adjuvant anti-HER2 therapy: Analysis of 397 cases [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P1-02-14.