2306P - How TAILORx changed treatment allocation based on 21-gene recurrence score in the daily clinic: A single center retrospective analysis

Background

Results from TAILORx showed significant benefit of chemotherapy (CHT) in premenopausal early luminal HER2-negative breast cancer (BC) patients with a 21-gene intermediate recurrence score (RS). We analysed how this data shifted CHT implementation after July 2018 (cut-off), especially in the intermediate RS group, in order to determine how the reality of the daily clinic met the new standard guidelines.

Methods

Retrospective analysis in a cohort of 326 HER2-negative, luminal BC patients, treated at Basel University Hospital and Cantonal Hospital Baselland (2010-2021). Primary end-point was to assess any change in therapy administration in the BC population before (cohort A) and after the cut-off point (cohort B) adjusted after RS categories and determine role of menopausal status and RS in CHT selection.

Results

RS values across all categories were lower in B vs A in the low (p<0.001), intermediate (p=0.001) and high RS (p=0.005). The intermediate and high RS groups were larger in B vs A (97 vs 52, 27 vs 14 patients, p<0.001), while low RS was smaller (37 vs 99, p<0.001). In the low and high RS there was less radiotherapy in B vs A (54.5% vs 71%, p=0.01 and 26% vs 50%, p=0.039), but no difference in other treatments. Menopausal status, nor RS seem to drive therapy. In the intermediate RS, there was less CHT in B vs A (13% vs 40%, p=0.001) and less patient refusal of CHT (4% vs 15%, p=0.01). In this category, CHT regimen changed significantly in B vs A with less anthracycline + taxotere applications (81% vs 61.5%, p=0.009). There was also more bisphosphonate therapy in B vs A (84% vs 65%, p=0.007). In this RS category, CHT was significantly impacted by menopausal status and RS in A (p=0.002), but not in B (p=0.882). There was more Tumor Board (TB) convergence on treatment for patients with intermediate RS in B vs A (87% vs 68%, p=0.039). When not adjusted for RS categories, menopause was not significant for CHT administration (p=0.121 in A, p=0.384 in B), but RS was (p<0.001 in A and B).

Conclusions

TAILORx significanlty impacted CHT administration, regimen selection, compliance and TB decision convergence in the intermediate RS group. When not adjusted for RS categories, menopausal status was not decisive for CHT, but independently, RS score was.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

PD Dr. med. Marcus Vetter.

Funding

Has not received any funding.

Disclosure

M.H.F. Vetter: Financial Interests, Institutional, Research Grant: Exact Sciences. All other authors have declared no conflicts of interest.