Long-term outcome data for patients with hormone receptor-positive early breast cancer participating in the WSG PlanB trial after preselection by gene expression analysis: 10-year survival results from the WSG PlanB registry.

BACKGROUND

The PlanB registry evaluated long-term follow-up data for clinical candidates for chemotherapy enrolled in the PlanB trial in hormone receptor (HR)-positive early breast cancer (eBC) patients preselected using the 21-gene expression assay.

PATIENTS AND

METHODS

PlanB randomly assigned pT1-4c, pN+, pN0/high-risk human epidermal growth factor receptor 2 (HER2)-negative eBC patients to four cycles of epirubicin + cyclophoshamide followed by four cycles of docetaxel (EC-T arm) or to six cycles of docetaxel + cyclophosphamide (TC); patients with locally HR-positive tumors and recurrence score (RS) <12 received endocrine therapy (ET) only. Following the end of PlanB, patients with HR-positive tumors were included in a prospective, noninterventional PlanB registry. The primary objective was to compare invasive disease-free survival (iDFS); the secondary objectives were the comparisons of overall survival (OS), and distant disease-free survival (dDFS).

RESULTS

The registry included 699 patients (ET only: n = 119, TC: n = 298, EC-T: n = 289). In the TC and EC-T groups, respectively, 41% and 41% were postmenopausal; 63% and 55% were pN0; and 23% and 24% had RS >25. Ten-year survival rates (10.3 years median follow-up) in the TC and EC-T arms were, respectively, 90.8% [95% confidence interval (CI) 86.6% to 93.7%] and 92.1% (95% CI 88.2% to 94.7%, P = 0.546) for iDFS; 94.4% (95% CI 90.9% to 96.5%) and 93.2% (95% CI 89.5% to 95.6%, P = 0.789) for dDFS, and 96.8% (95% CI 94.0% to 98.3%) and 96.3% (95% CI 93.3% to 98.0%, P = 0.974) for OS. Overall, 10-year OS was 94.2% (95% CI 88.9% to 97.1%) in RS <12 (77.9% received ET-only), 96.8% (95% CI 94.4% to 98.2%) in RS 12-25, and 96.1% (95% CI 90.9% to 98.4%) in RS >25 group. RS was not predictive of the efficacy of EC-T versus TC.

CONCLUSIONS

Ten-year outcomes for TC and EC-T were similar and excellent; six cycles of TC is an effective option in HER2-negative eBC with pN0 or pN1 and intermediate-to-high-risk disease, according to gene expression analysis.