Real-world evidence on recurrence risk from clinicopathologic features in HR+/HER2− early breast cancer patients using Chinese electronic health records.

e13085 Background: The NATALEE trial demonstrated the benefits of ribociclib based treatment in a broad population with HR+/HER2− early breast cancer (eBC). However, the risk of recurrence (RoR) of NATALEE study subgroups including N0 patients (pts) especially for T2N0 is limited reported. Our study aimed to evaluate the RoR based on clinicopathologic features including those N0 pts in HR+/HER2- eBC within a Chinese population. Methods: The retrospective real-world study analyzed the HR+/HER2− eBC (stages I-III) pts diagnosed between January 2013 and December 2022 from the Chinese National Cancer Database. Eligible pts underwent surgery and received adjuvant therapy. All pts were classified based on the NATALEE selection criteria: Group 1 included non-NATALEE pts. Among the NATALEE eligible pts, Group-2 included T2N0 pts with risk factors of grade 3, or grade 2 with a Ki-67≥20%; Group-3 covered T3-4N0 Pts; Group-4 were N1 pts; Group-5 were N2-3 Pts. Real-world invasive disease-free survival (rwiDFS) was calculated from surgery to recurrence or death, using Kaplan-Meier and Cox proportional hazards models. Results: In total, 28,623 pts were entered onto the analysis: 58.49% (n = 16,743) were NATALEE eligible pts, and 33.01% (n = 9,474) were non-NATALEE pts, other 8.50% (n = 2406) is excluded duo to missing data. Compared to Group-1 (non-NATALEE), the whole NATALEE-eligible pts has significant higher RoR with HR 3.03 [95% CI: 2.73–3.37], P < 0.0001. Also, all other 4 groups among NATALEE eligible pts have demonstrated significant higher RoR respectively: T2N0 pts with risk factors (HR 2.01 [95% CI: 1.70-2.38], P < 0.0001), T3-4N0 pts (HR 3.23 [95% CI: 2.38-4.38], P < 0.0001) , N1 pts (HR 2.30 [95%CI: 2.04-2.58], P < 0.0001) and N2-N3 pts (HR 4.80 [95%CI: 4.28-5.39], P < 0.0001). Further comparison between different Node status showed that, the N0 Pts, including T2N0 with risk factors and T3-4N0 pts, demonstrated numerally similar or even higher RoR respectively compared to N1 pts across the 3- to 10-year time. Conclusions: This study indicated that NATALEE-eligible pts faced a 3 times higher risk of recurrence or death compared to non-NATALEE pts. Even T2N0 pts with risk factors exhibited comparable recurrence risks with N1 pts, which is twice higher than non-NATALEE pts. Intensive adjuvant therapy need to be considered for those pts. Summary of rwiDFS results. Non-NATALEE NATALEE eligible Group-1N=9474 TotalN=16743 Group-2(High-risk T2N0)N=2646 Group-3(T3-T4N0)N=364 Group-4(N1)N=8690 Group-5(N2-N3)N=5043 HR, 95%CI Ref 3.03[2.73-3.37] 2.01 [1.70-2.38] 3.23 [2.38-4.38] 2.30 [2.04-2.58] 4.80 [4.28-5.39] P-value -- <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 rwiDFS rate 3y 96.79% 89.21% 93.14% 88.55% 91.80% 83.10% 5y 93.37% 81.37% 86.86% 79.49% 85.80% 72.00% 7y 88.24% 72.84% 79.81% 70.55% 79.38% 60.03% 10y 82.92% 56.07% 63.01% 70.55% 60.90% 44.81%