Abstract P1-06-06: No age-related outcome disparities according to 21-gene recurrence score groups in early breast cancer patients treated by adjuvant chemotherapy in the prospective WSG PlanB trial
Authors: Harbeck N , Gluz O , Wuerstlein R , Clemens M , Malter W , Reimer T , Nuding B , Stefek A , Pollmanns A , Augustin D , Uleer C , Lorenz-Salehi F , Shak S , Chao C , Christgen M , Kates R , Kreipe H , Nitz U 
Published: February 2018

Background: Elderly breast cancer (BC) patients (pts) have been reported to have worse BC-related outcome than younger pts, even within clinical trials such as TEAM. Shak et al. recently showed in a large SEER data analysis that in the high 21-gene recurrence score (RS) group, older pts (&gt;70y) receive less chemotherapy (CT) and have a worse BC-specific mortality than younger pts. Here, we therefore aimed to see whether there are age-related outcome disparities according to RS groups in pts receiving state-of-the-art CT in the prospective WSG PlanB trial.

Material and Methods: PlanB compared 6 cycles of anthracycline-free TC vs. standard anthracycline-taxane based CT (4xECà4xDoc) in patients with high risk pN0 (T2-4, G2-3, &lt;35 years, or high uPA/PAI-1) or pN+ HER2- early BC. 21-gene assay was performed in all HR+ tumors and omission of chemotherapy (CT) recommended in RS≤11 HR+ pN0-1 BC. Final analysis for the CT randomization for RS 12-25 after 60 months median follow-up revealed similar 5-year DFS and OS outcomes for both CT arms (ASCO 2017).

Results: In all pts with luminal cancer and RS results (n=2577), there was an age-related significant difference in RS risk group assignment (p&lt;0.0001): in young pts (&lt;40y), 9.1% had RS≤11, 52.7% RS 12-25, and 38.2% RS&gt;25; in pts 40-69 years, 18.3% had RS≤11, 61% RS 12-25, and 20.7%% RS&gt;25; in elderly pts (&gt;70y), 19.5% had RS≤11, 55.3% RS 12-25, and 25.2% RS&gt;25. Among patients receiving chemotherapy, RS&gt;25 vs. RS&lt;25 was associated with significantly poorer DFS separately within the elderly subgroup (HR=3.03, 95%-CI [1.15-7.96]) and in those aged 40-69 years (HR=3.14, 95%-CI [2.18-4.52]); there were only nine events among patients &lt;40y. In particular, among pts receiving CT with RS&gt;25, there were no significant differences in DFS between any two of these three age groups.

Conclusion: A substantial percentage of elderly patients (&gt; 70y) presents with high-risk luminal disease; these patients are candidates for CT. In PlanB, about 25% of elderly luminal BC patients had high-risk (RS&gt;25) tumors. Nevertheless, after receiving modern adjuvant CT, their DFS was comparable to that of non-elderly pts with high-risk RS tumors. Consequently, older BC pts with high-risk luminal tumors who are fit enough to receive adjuvant CT should be treated according to guidelines in order to overcome age-dependent survival disparities which have been observed in registries for high-RS tumors.

Citation Format: Harbeck N, Gluz O, Wuerstlein R, Clemens M, Malter W, Reimer T, Nuding B, Stefek A, Pollmanns A, Augustin D, Uleer C, Lorenz-Salehi F, Shak S, Chao C, Christgen M, Kates R, Kreipe H, Nitz U. No age-related outcome disparities according to 21-gene recurrence score groups in early breast cancer patients treated by adjuvant chemotherapy in the prospective WSG PlanB trial [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-06-06.