Abstract P6-11-04: Use of Mammaprint© (MMP) genetic signature in early breast cancer patients. Economic analisys of a 129 patient cohort treated in three Spanish hospitals

Abstract

Abstract Introduction: Benefit derived from adjuvant chemotherapy (CT) is doubtful in a high percentage of patients with early breast cancer. The 70-genes platform MMP improves prognostic classification and has been proven useful when it comes to individualizing treatment options. At our institution we use this test to try to avoid overtreatment in those patients in which CT benefit is unclear. We defined some criteria in order to discriminate better which patients would benefit most from the MMP assessment as well as to identify a group of subjects where the test would be more cost-effective. These criteria were: age between 35-70 years, tumor size from 1 to 3 cm, histological grade 2, absence of macrometastatic disease in axillary nodes, hormone receptors positive, HER2 negative and Ki67 between 11-25%. Objective: To analyze the impact of using MMP to help selecting adjuvant treatment, both in clinical and economical aspects. Material and Methods: Since August 2012 to January 2015, MMP genetic signature was performed in 129 early tumors samples. Most cases met the criteria explained above. Some that did not were also included by decision of the institution multidisciplinary committee when the individual characteristics of the cases where taken into account. We compiled the adjuvant treatment initially planned according to our institution protocol and usual clinical practice and compared it with the actual treatment given after the results of the test were known. We calculated the direct economic costs of chemotherapy and of the diagnostic test. Results: The clinical characteristics of the patients and the adjuvant therapy they received are shown in Table 1. Patients Characteristicsn=129 Age, median (range)54.5 (20-76)Histology Infiltrating ductal carcinoma115 (89%)Infiltrating lobular carcinoma14 (11%)pT (mm) Median (range)15 (8-60)Mean (range)18.55 (8-60)pN pN087 (67.4%)pN1mic30 (23.2%)pN17 (5.4%)pN21 (0.8%)Histological grade I24 (18.8%)II100 (78.1%)III4 (3.1%)Hormone receptors ER 50-100%129 (100%)PR <20%21 (16.3%)PR >20%108 (83.7%)Ki 67 <=20%74 (57.8%)> 20%54 (42.2%)Median (range)20 (1-35)Mean (range)19.95 (1-35)Her 2 negative129 (100%)Adjuvant treatment FEC-paclitaxel + Hormonotherapy18TAC + Hormonotherapy27Hormonotherapy84 119 Patients (92.2%) would have received adjuvant CT without MMP risk determination. After the results only 45 patients (34.9%) received it. The cost of the genetic study was 306.725€. Direct costs savings estimated from the reduction in CT treatment were 494.771,48 €. Conclusion: The use of the MMP test in a selected group of patients reduced the administration of adjuvant CT in a 57.3%. This represented a saving of 188.046,48€. Citation Format: Rullan AJ, Pernas S, Margelí M, Joan D, Quiroga V, Stradella A, Petit A, Germà JR, Calle C, Falo C, Ponton JL, Gil-Gil M. Use of Mammaprint© (MMP) genetic signature in early breast cancer patients. Economic analisys of a 129 patient cohort treated in three Spanish hospitals. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-11-04.