Abstract GS2-02: Efficacy and utilization trends of adjuvant chemotherapy for stage I, II, and III breast cancer in the elderly population: A National Cancer Database (NCDB) analysis
Authors: Sinha S , Panebianco L , Wu X , Wang D , Huang D , Sivapiragasam A 
Published: May 2019

Abstract
Background: The role of adjuvant chemotherapy in early stage breast cancer is well established with survival benefit seen in long term follow up studies, but only a small minority of patients in these studies were &gt;65 years old. Dose and schedule can be tailored according to the special requirements of an elderly patient, as stated by the International Society of Geriatric Oncology (SIOG). However the magnitude of the benefit and trends in utilization of adjuvant chemotherapy has not been well studied in this population.
Methods: Female patients above 65 years age with stage I to III breast cancer were identified from the NCDB database from 2004-2015. Factors predicting utility of chemotherapy were assessed with multivariate analysis. Kaplan Meier curves were constructed for calculation of overall survival (OS) with hazard ratio (HR) estimated from cox model. Log rank test and pearson chi square was used for comparison between groups. Groups were compared for OS benefit at 5 and 10 years.
Results: Of a total of 2,445,730 patients analyzed, 160,676 met our inclusion criteria. Of them, 21,743 were &gt;80 years old. Factors predicting use of adjuvant chemotherapy were shown in table 1. OS benefit was seen in patients who received adjuvant chemotherapy regardless of their age, ER, PR, HER-2 status or stage. Patients with TNBC had an HR of 0.547. More benefit was seen in the higher stages. HR for stages I, II, and III were 0.801, 0.608, and 0.666 respectively.
Table 1-Factors predicting utilization of adjuvant chemotherapy No chemotherapyWith chemotherapyp-valueHistology &lt;0.0001 All others9980 (16.8)12502 (13.9) Ductal, infiltrating43453 (73)69631 (77.2) Lobular6107 (10.3)8073 (8.9) Grade &lt;0.0001 Well differentiated15268 (25.6)8182 (9.1) Moderately differentiated28813 (48.4)36028 (39.9) Poorly differentiated15459 (26.0)45996 (51.0) Age &lt;0.0001 &gt;8015766 (26.5)4501 (5.0) 65-8043774 (73.5)85705 (95.0) Race &lt;0.0001 Black5150 (8.6)9882 (11.0) White52420 (88.0)76956 (85.3) Others1970 (3.3)3368 (3.7) CDCC &lt;0.0001 043902 (73.7)70256 (77.9) 111883 (20.0)16219 (18.0) 22840 (4.8)3053 (3.4) &gt;3915 (1.5)678 (0.8) Radiation Therapy &lt;0.0001 With Radiation28978 (48.8)57507 (64.1) Without Radiation30395 (51.2)32184 (35.9) Type of Surgery &lt;0.0001 Local/partial mastectomy35823 (60.2)43026 (47.7) Mastectomy1234 (2.1)1005 (1.1) None22467 (37.7)46112 (51.2) Stage &lt;0.0001 133574 (56.4)27829 (30.9) 220544 (34.5)41087 (45.5) 35422 (9.1)21290 (23.6) ER/PR Status &lt;0.0001 +/+42842 (73.1)46000 (52.0) +/-7049 (12.0)13033 (14.7) -/+451 (0.8)1315 (1.5) -/-8279 (14.1)28155 (31.8)
Conclusions: Adjuvant chemotherapy is considered standard of care for patients with early stage breast cancer. Elderly patients are more likely to get adjuvant chemotherapy based on histology, age&lt;80, grade, stage, and hormone receptor status. In this study, we also learn that the OS benefit with adjuvant chemotherapy is significant in all subgroups analyzed for the elderly population.
Citation Format: Sinha S, Panebianco L, Wu X, Wang D, Huang D, Sivapiragasam A. Efficacy and utilization trends of adjuvant chemotherapy for stage I, II, and III breast cancer in the elderly population: A National Cancer Database (NCDB) analysis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS2-02.