Assessment of risk of overall and late distant recurrence by Breast Cancer Index in postmenopausal women with early-stage, HR+ breast cancer in the TEAM trial

• Published in: Journal of clinical oncology Vol. 41; no. 16_suppl; p. 509
• Main Authors: Bartlett, John MS, Xu, Keying, Wong, Jenna, Pond, Gregory Russell, Zhang, Yi, Spears, Melanie, Salunga, Ranelle C., Mallon, Elizabeth, Taylor, Karen J, Hasenburg, Annette, Markopoulos, Christos, Dirix, Luc Yves, Seynaeve, Caroline M., Van De Velde, Cornelis J.H., Rea, Daniel William, Schnabel, Catherine A, Treuner, Kai, Bayani, Jane
• Format: Journal Article
• Language: English
• Published: 01.06.2023
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/JCO.2023.41.16_suppl.509

509 Background: Individual risk assessment of distant recurrence (DR) is particularly relevant for early-stage HR+ breast cancer patients, as they face a prolonged risk of recurrence even after adjuvant endocrine therapy. Previously, we have shown that the Breast Cancer Index (BCI) and BCIN+ risk groups are significantly prognostic for risk of overall (0-10y) and late (5-10y) distant recurrence in N0 and N1 breast cancer patients, respectively, enrolled in the Tamoxifen and Exemestane Adjuvant Multinational (TEAM) trial. Here, the prognostic performance of BCI and BCIN+ as a continuous risk score for overall and late distant recurrence was evaluated in the TEAM trial. Methods: BCI testing was performed blinded to clinical outcome with BCI/BCIN+ risk scores calculated as previously described. Cox proportional hazard models adjusted for age, tumor size, grade and treatments were used to estimate hazard ratios (HRs) and the associated 95% confidence intervals (CIs) for BCI/ BCIN+ continuous risk scores. The 10y risk of overall and late DR were estimated as a function of risk scores from the Cox models using Breslow estimates. Results: Continuous risk curves for overall and late DR were obtained in patients who did not receive adjuvant chemotherapy and those who remained DR-free at 5 years regardless of chemotherapy, respectively, to reflect the two key time points for breast cancer treatment decision-making. InN0 patients not treated with chemotherapy (N = 1197), BCI was significantly prognostic for overall DR with a HR of 1.39 (95% CI 1.25-1.54; p < 0.001), while BCIN+ was significantly prognostic in N1 patients who did not receive chemotherapy (N = 1319) with a HR of 4.29 (95% CI 2.93-6.28; p < 0.001). Among patients who remained DR-free at 5 years, in the N0 subset (N = 1285), BCI was significantly prognostic for late DR with a HR of 1.23 (95% CI 1.07-1.42; p < 0.001), while BCIN+ remained to be significantly prognostic in the N1 subset (N = 1762) with a HR of 2.78 (95% CI 1.75-4.43; p < 0.001). Similar results were observed in the HER2- subset for both overall and late DR. Continuous risk curves for BCI and BCIN+ for overall and late DR showed an increasing risk of DR with higher BCI/BCIN+ scores. Conclusions: Results from this largest BCI study to date further support the use of BCI to provide individualized risk estimates for both overall and late DR in women with HR+ breast cancer to aid in personalized decision-making for adjuvant therapy. [Table: see text]