Abstract P4-13-10: The outcome of lung metastasis treated with fulvestrant is superior to that of liver metastasis for metastatic breast cancer

Abstract

Abstract Background: Endocrine therapy is the preferred option in patients presenting with hormone receptor (HR)-positive metastatic breast cancer (MBC). While visceral metastasis is a negative prognostic factor, few studies have distinguished between the prognosis of different visceral sites. Patients and methods: 505 HR-positive MBC patients administered with fulvestrant at Fudan University Shanghai Cancer Center during a 6-year period were enrolled, 398 patients receiving fulvestrant 500mg were included in final analysis. Logistic regression models were used to identify prognostic factors associated with progression-free survival (PFS). Kaplan-Meier analysis was utilized to compare PFS of lung and liver metastases. Results: Median follow-up time was 26 months. 233 patients presented with baseline visceral metastases, including 138 lungw/o liver metastases (lung metastasis without liver involvement), 51 liverw/o lung metastases (liver metastasis without lung involvement), and 41 with both lung and liver metastases. Median PFS was 6.8 months (5.6 months for visceral metastases, 9.2 months for non-visceral metastases, P = 0.028). Lungw/o liver metastases had longer median PFS compared to liverw/o lung metastases or both lung and liver metastases (9.6 months, 3.7 months and 3.2 months, respectively, P < 0.001). In addition, patients with liver metastases experienced a significantly worse PFS when compared with those without liver involvement (3.7 versus 9.2 months, P < 0.001). In multivariate analyses, PFS benefits of fulvestrant were observed in patients with longer disease-free interval, absence of liver metastases, and no previous chemotherapy for MBC. Table 1.Univariate and multivariate analysis of progression-free-survival by prespecified stratification factors.VariablesN Univariate Multivariate Mediana95% CIPHR95% CIPMenopausal status Premenopausal8411.06.4-15.7 ---Postmenopausal3145.94.7-7.10.052---Disease-free interval > 5 y1818.65.8-11.5 1 ≤ 5 y1714.83.6-6.00.0031.421.01-1.990.043PgR status Positive2856.95.3-8.6 ---Negative + UK1135.54.6-6.30.107---Bone-only metastasis Yes6110.92.7-19.0 1 No3375.84.8-6.80.0021.690.91-2.800.06Metastatic sites Non-visceral1659.26.7-11.7 1 Lungw/o liver1389.65.3-13.90.860---Liver923.72.9-4.5<0.0011.511.05-2.180.027ET naïve Yes3226.8NE-59.3 1 No3666.04.9-7.20.012.120.99-4.540.052Prior ET for metastatic disease 014511.05.5-16.6 1 ≥12535.64.9-6.30.0020.910.62-1.340.645Sensitivity to prior ET Primary resistance714.02.9-5.0 ---Secondary resistance2957.05.6-8.30.05---Prior chemotherapy for metastatic disease 02039.96.5-13.2 1 ≥11954.73.9-5.5<0.0011.931.32-2.820.001Abbreviations: PgR, progesterone receptor; UK, unknown; HR, hazard ratio; 95% CI, 95% confidence interval; ET, endocrine therapy; NE, not estimable. Lungw/o liver, lung metastasis without liver involvement. aMedian PFS in months. P < 0.05 was considered significant, significant values was presented in bold. Conclusion: Patients with lungw/o liver metastases benefit as well as those with non-visceral metastases from fulvestrant. Visceral metastases should distinguish between liver or lung when treating HR-positive/HER2-negative MBC with endocrine therapy. Citation Format: He M, Li J-J, Zuo W-J, Ji L, Hu X-C, Wang Z-H, Shao Z-M. The outcome of lung metastasis treated with fulvestrant is superior to that of liver metastasis for metastatic breast cancer [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 P4-13-10.