Hayes, Daniel F

Abstract Purpose: The aim of PREDICT was to confirm clinical validity and the potential for clinical utility of serial circulating tumor cell (CTC) enumeration in patients with metastatic breast cancer, focusing on its prognostic value in different breast cancer subtypes and clinical settings. Experimental Design: In total, 4,436 individual patient-level data with CTC results from both baseline and one follow-up (CellSearch; Menarini Silicon Biosystems) were analyzed to evaluate the association between CTC detection and overall survival (OS) in the full patient cohort and separately for tumor and treatment types. Results: Using the cutoff ≥1 CTC for CTC positivity, 913 (20.6%) patients had 0 CTCs at both time points (neg/neg) and 325 (7.3%) and 1,189 (26.8%) patients converted from CTC negative to CTC positive (neg/pos) or vice versa (pos/neg), whereas 2,009 (45.3%) patients had at least one CTC at both time points (pos/pos). The median OS for the neg/neg, neg/pos, pos/neg, and pos/pos group was 45.6, 26.1, 32.3, and 17.3 months, respectively (P < 0.0001, global log-rank test). CTC responders (pos/neg) showed a lower risk of death compared with CTC nonresponders (pos/pos; HR, 0.48; 95% confidence interval, 0.44–0.53). Similar results were obtained in subgroup analyses according to hormone receptor and HER2 subtype, treatment type, and with a ≥5 CTC cutoff for CTC positivity. Conclusions: Follow-up CTC assessments strongly predict OS independently from tumor subtype and treatment. New randomized trials to define the clinical utility of CTC monitoring for risk stratification and as an early response marker in metastatic breast cancer are urgently needed.

Abstract Background The phase III RxPONDER trial has affected treatment for node-positive (1-3), hormone receptor-positive, HER2-negative breast cancer with a 21-gene recurrence score (RS) less than 26. We investigated how these findings apply to different racial and ethnic groups within the trial. Methods The trial randomly assigned women to endocrine therapy (ET) or to chemotherapy plus ET. The primary clinical outcome was invasive disease-free survival (IDFS), with distant relapse-free survival (DRFS) as a secondary outcome. Multivariable Cox models were used to evaluate the association between race/ethnicity and survival outcomes, adjusting for clinicopathological characteristics, RS, and treatment. Results A total of 4048 women with self-reported race/ethnicity were included: Hispanic (15.1%), non-Hispanic Black (NHB) (6.1%), Native American/Pacific Islander (0.8%), Asian (8.0%), and non-Hispanic White (NHW) (70%). No differences in RS distribution, tumor size, or number of positive nodes were observed by race/ethnicity. Relative to NHWs, IDFS was worse for NHB participants (5-year IDFS 91.6% vs 87.1%, HR = 1.37; 95% CI = 1.03 to 1.81) and better for Asians (91.6% vs 93.9%, HR = 0.64; 95% CI = 0.46 to 0.91). Relative to NHW, DRFS was worse for NHB participants (5-year DRFS 95.8% vs 91.0%, HR = 1.65; 95% CI = 1.17 to 2.32) and better for Asians (95.8% vs 96.7%, HR = 0.59; 95% CI = 0.37 to 0.95). Adjusting for clinical characteristics, particularly body mass index, diminished the effect of race on outcomes. Chemotherapy treatment efficacy did not differ by race/ethnicity. Conclusions NHB women had worse clinical outcomes compared with NHWs in the RxPONDER trial despite similar RS and comparable treatment. Our study emphasizes the persistent racial disparities in breast cancer outcomes while highlighting complex interactions among contributing factors. Trial Registration ClinicalTrials.gov: NCT01272037.