Abstract P5-08-33: Decreased overall survival in "young" breast cancer patients with renal insufficiency
Authors: Launay-Vacher V , Janus N , Ray-Coquard I , Thariat J , Deray G , Beuzeboc P 
Published: May 2016

Abstract
Background
Data still remain scanty on the potential impact of chronic kidney disease (CKD) on the mortality of breast cancer (BC) patients. The results of 3 clinical studies we conducted (IRMA-2, CANDY and MARS) were pooled. In all 3, the methodology was the same regarding CKD, allowing pooled analysis on the prevalence of CKD and on the potential association between RI and overall survival (OS), and to stratify the risk, if any, depending on the GFR.
Material and methods
The KDIGO definition and classification of CKD was used. GFR was estimated with the MDRD formula. RI was defined as GFR&lt;60 ml/min/1.73 m2. Multivariate analysis was conducted using patients with a GFR ≥ 90 ml/min/1.73m2 as the reference. This sub-group analysis presents the results for young (&lt;65 years) BC patients
Results
The total population included 5908 solid cancer patients, among them, 1716 were young BC patients. Median age: 53.0 years, median body mass index: 23.4 kg/m2, bone metastasis: 27.7%, visceral metastasis: 38.7%. 75.9% of these patients were alive at the end of the 1-year follow-up. In these young BC patients, prevalences of a GFR&lt;90 and &lt;60 mL/min/1.73m2 were 46.6% and 5.4%, respectively (no dialysis patients). Multivariate Cox model adjusted for age, and metastasis reported that GFR was significantly associated with OS with an increased risk of mortality at a GFR of 71 mL/min/1.73m2 (HR=1.51 [1.10-2.08]; p=0.04). This risk gradually increased with the decrease in GFR (table), except for patients below 30 mL/min/1.73m2, however still significantly increased.
Conclusion:
This pooled analysis reported that: 1) abnormal GFR was frequent in young BC patients, 2) reduced GFR was a statistically significant prognostic factor for reduced OS. 3) This reduced OS began at an early stage of CKD in young BC patients, for a GFR&lt;71 ml/min/1.73m2. These results underline that assessing, monitoring and managing renal function in BC patients is crucial, and for relatively high levels of GFR. Preventing the reduction in renal function requires early care, multidisciplinary, or a transfer of good practices from nephrologists to oncologists involved in the care of these patients. Recommendations from the Cancer & the Kidney International Network (C-KIN), recently founded, are to be released.
Table. Multivariate Cox model regressions in BC patientsGFRn, %HR [95% CI]; p-value as compared to GFR ≥ 90GFR&lt;90799 (46.6%)HR=1.22 [0.79-1.89]; p&gt;0.05GFR&lt;80501 (29.2%)HR=1.11 [0.84-1.47]; p&gt;0.05GFR&lt;70238 (13.9%)HR=1.60 [1.15-2.22]; p=0.005GFR&lt;6092 (5.4%)HR=1.80 [1.14-2.86], p=0.012GFR&lt;5033 (1.9%)HR=2.38 [1.22-4.63]; p=0.01GFR&lt;4012 (0.7%)HR=2.77 [1.27-6.03]; p=0.011GFR&lt;305 (0.3%)HR=1.67 [1.04-2.69]; p=0.04
Citation Format: Launay-Vacher V, Janus N, Ray-Coquard I, Thariat J, Deray G, Beuzeboc P. Decreased overall survival in "young" breast cancer patients with renal insufficiency. [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 P5-08-33.