Abstract P6-10-01: Risk of chemotherapy-induced febrile neutropenia (FN) in patients (pts) with non-metastatic breast cancer (BC) and documented risk factors for FN
Authors: Weycker Derek , Li Xiaoyan , Barron Richard , Wu Hongsheng , Morrow Phuong Khanh , Xu Hairong , Reiner Maureen , Garcia Jacob , Mhatre Shivani , Lyman Gary 
Published: May 2015

Background: Clinical practice guidelines recommend primary prophylactic colony-stimulating factor (CSF) for pts with cancer receiving myelosuppressive chemotherapy when their risk of FN is high (≥20%). Evaluating FN risk in pts who receive regimens that are not documented as high risk in guidelines can be challenging; these pts may be at a high risk of developing FN based on a combination of regimen and pt risk factors. This retrospective study estimated FN risk among subgroups of pts with non-metastatic BC receiving 1 of 3 commonly used, non-high risk chemotherapy regimens.

Methods: Pt-level data from 2 US healthcare claims databases comprising medical and outpatient pharmacy claims from commercial and Medicare supplemental plans were pooled. Eligible pts were ≥18 years old and had initiated a course of TC, TCH, or non-dose-dense AC/AC-T for non-metastatic BC between July 1, 2003 and June 30, 2012. Occurrence of FN during any cycle of the first chemotherapy course was identified using diagnosis codes for neutropenia, fever, or infection. Risk factors, documented in guidelines and the published literature, were evaluated during the 12 months before chemotherapy initiation. The percentage of pts, FN risk, and relative risk (RR, compared to pts with no risk factors) for subgroups of pts with specific risk factors are presented.

Results: 50,893 pts were included in the analysis. FN risks by chemotherapy regimen and subgroup are shown in the table.

 TC N=26,266TCH N=9,105AC/AC-T N=15,522 % PtsFN Risk (RR, 95% CI)% PtsFN Risk (RR, 95% CI)% PtsFN Risk (RR, 95% CI)Any risk factor78.114.2 (1.4, 1.3-1.5)74.516.9 (1.3, 1.2-1.5)73.616.6 (1.6, 1.4-1.7)Age ≥6515.116.3 (1.6, 1.4-1.7)11.516.3 (1.3, 1.1-1.5)11.417.9 (1.7, 1.5-1.9)Chronic comorbidities      Cardiovascular disease16.816.9 (1.6, 1.5-1.8)14.620.2 (1.6, 1.4-1.8)16.619.5 (1.8, 1.6-2.1)Diabetes11.817.4 (1.7, 1.5-1.9)10.221.3 (1.7, 1.4-2.0)11.120.4 (1.9, 1.7-2.2)Liver disease1.918.7 (1.8, 1.5-2.2)2.220.8 (1.6, 1.2-2.2)2.017.8 (1.7, 1.3-2.2)Lung disease2.023.4 (2.3, 1.9-2.7)1.530.7 (2.4, 1.8-3.2)1.927.1 (2.6, 2.1-3.2)Renal disease1.322.7 (2.2, 1.8-2.7)0.925.0 (2.0, 1.3-2.9)1.026.8 (2.5, 1.9-3.3)Osteoarthritis7.019.6 (1.9, 1.7-2.1)6.121.1 (1.7, 1.4-2.0)6.020.8 (2.0, 1.7-2.3)Thyroid disorder13.015.4 (1.5, 1.3-1.7)11.917.4 (1.4, 1.2-1.6)10.617.2 (1.6, 1.4-1.9)Number of risk factors      133.211.7 (1.1, 1.0-1.2)33.914.1 (1.1, 1.0-1.3)33.714.2 (1.3, 1.2-1.5)224.613.8 (1.3, 1.2-1.5)23.217.4 (1.4, 1.2-1.6)22.916.0 (1.5, 1.3-1.7)312.516.3 (1.6, 1.4-1.8)11.219.8 (1.6, 1.3-1.8)11.121.3 (2.0, 1.8-2.3)4+7.822.8 (2.2, 2.0-2.5)6.125.0 (2.0, 1.6-2.3)5.924.8 (2.3, 2.0-2.7)Reference group (0 risk factor)21.910.4 (NA)25.512.7 (NA)26.411.6 (NA)Selected risk factors are presented.

A high proportion of pts (74%-78%) had ≥1 risk factor for FN, and these pts had a higher FN risk than pts with no risk factors. 55.4%, 56.7%, and 42.2% of all pts who received TC, TCH, or AC/AC-T, respectively, received CSF prophylaxis in cycle 1.

Conclusions: FN risk assessments are needed for pts who are receiving non-high risk regimens.

Citation Format: Derek Weycker, Xiaoyan Li, Richard Barron, Hongsheng Wu, Phuong Khanh Morrow, Hairong Xu, Maureen Reiner, Jacob Garcia, Shivani Mhatre, Gary Lyman. Risk of chemotherapy-induced febrile neutropenia (FN) in patients (pts) with non-metastatic breast cancer (BC) and documented risk factors for FN [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-10-01.