(S046) Prognosis for Patients With Metastatic Breast Cancer Who Achieve ‘No-Evidence-of-Disease’ Status After Systemic or Local Therapy

Andrew J. Bishop, Joe Ensor, Stacy L. Moulder, Simona F. Shaitelman, Mark A. Edson, Gary J. Whitman, Sandra Bishnoi, Karen E. Hoffman, Michael C. Stauder, Vicente Valero, Thomas A. Buchholz, Naoto T. Ueno, Gildy Babiera, Wendy A. Woodward; UT MD Anderson Cancer Center; Rice University

PURPOSE/OBJECTIVES: Newer systemic therapy regimens are more commonly associated with complete or near-complete radiographic response in patients with metastatic breast cancer (MBC). We investigated outcomes for patients with MBC with no evidence of disease (NED) after treatment and identified factors that were predictive of outcome once NED status was achieved.

MATERIALS AND METHODS: We reviewed 570 patients with MBC consecutively treated between January 2003 and December 2005. NED was defined as a complete metabolic response by positron emission tomography (PET) and/or sclerotic healing of bone metastases on computed tomography (CT) or magnetic resonance imaging (MRI). Median follow-up was 27 months (range: 0–134 mo) for all patients and 100 months (range: 14–134 mo) for NED patients. The Kaplan-Meier method estimated overall survival (OS) and progression-free survival (PFS); log-rank tests assessed for equality among groups. Cox proportional hazard models were used. Estimated hazard ratios (HRs) are reported.

RESULTS: The 3- and 5-year OS rates for the entire group were 44% and 24% compared with 96% and 78%, respectively, for the NED subset (n = 90, 16%). Patients who attained NED status had a longer median survival (112 vs 24 months; P < .001), which correlated strongly with survival on multivariate analysis (P < .001; HR = 0.15). Several other factors were also associated with more favorable survival on multivariate analysis, including presenting with de novo MBC (P < .001; HR = 0.60) and distant metastases involving only bone (P < .001; HR = 0.52) or only lung (P < .001; HR = 0.47). Patients who developed NED were more likely to have a normal body mass index (BMI) (P < .001), have either estrogen receptor (ER)+ or human epidermal growth factor receptor 2 (HER2)+ tumors (P < .001), have single sites of metastasis (P < .001), and present with de novo MBC (P = .04) when compared with the non-NED group. For patients with NED, the 3- and 5-year PFS rates (after NED) were 54% and 38%, respectively, with a median NED duration of 41 months (range: 0–115 mo). The only characteristics associated with PFS after NED were receptor status (HER2+ 58 mo vs ER+ 35 mo vs TNBC 13 mo; P = .02), inflammatory breast cancer at presentation (28 mo vs 45 mo; P = .02), and trastuzumab use (73 mo vs 31 mo; P = .02). Of the 63 patients who had disease progression, 20 achieved a second NED status. Ultimately, 31 patients (34%) with NED remained in remission at last follow-up.

CONCLUSIONS: Achieving NED status correlates strongly with outcome in MBC, making this a potentially valuable short-term clinical trial endpoint akin to pathologic complete response. MBC patients who attain NED have prolonged survival, with perhaps up to one-third achieving complete remission.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org