Abstract 138P
Background
The risk of relapse in patients with hormone receptor (HR)-positive, HER2-negative breast cancer (BC) is known to only partially subside over time, persisting up to 20 years from diagnosis. An extended duration of endocrine therapy (ET) significantly reduces this risk. We aimed to describe the cumulative incidence of distant relapse (DR) and local relapse (LR) in a population of intermediate/high risk BC patients from real-world dataset with a long follow up.
Methods
Our analysis is based on a dataset including 941 patients diagnosed with early HR-positive BC between 2000 and 2007 at a large tertiary-level cancer center in Italy. Statistics were based on a competing risks regression model based on cause-specific proportional hazards, where LR and DR were considered competing events. The model was extended with intermediate states determined by initiation and termination of ET and the inclusion of duration of ET as a time-dependent covariate, among many other covariates under study. Here we present the predicted cumulative incidence of DR and LR at 10 years for a patient at intermediate/high clinical risk who had completed at least 8 years of ET. Intermediate/high risk was defined as N1 disease or tumor larger than 2 cm.
Results
Median age was 56 years. About 12% of the patients had N0 with a tumor diameter of 2 cm or more, while nodal involvement was reported in 40% of the patients. More than 60% received chemotherapy. The median follow-up was 152 months. Main results are reported in the table. Table: 138P
Predicted cumulative incidence of DR and LR at 10 years after 8 years of ET
| Stage | DR | LR | ||
| G2 | G3 | G2 | G3 | |
| pT1N1 | 6.2 (0.2-28.5) | 7.2 (0.3-29.6) | 10.6 (2.7-24.9) | 7.7 (1.9-19.3) |
| pT2N0 | 2.3 (0.1-13.6) | 7.5 (0.3-32.1) | 4.6 (1-12.8) | 3.5 (0.6-10.7) |
| pT2N1 | 9.1 (0.1-42.4) | 13.6 (0.48-47.4) | 5.9 (1.1-17) | 4.3 (0.8-12.8) |
Conclusions
Long term incidence of distant or local relapse remain an unmet need, even in patients treated with extended ET. Biological factors as TN status and grade have an impact on late relapse.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
F. Girardi: Financial Interests, Personal, Other, travel support: Eli Lilly, Gilead; Financial Interests, Personal, Invited Speaker, honoraria for lectures: AstraZeneca, Eli Lilly; Financial Interests, Personal, Invited Speaker, onoraria for lectures: Gilead. M.V. Dieci: Financial Interests, Personal, Advisory Role: Eli Lilly, Pfizer, Novartis, Seagen, Gilead, MSD, Exact Sciences, AstraZeneca, Roche, Daiichi Sankyo. V. Guarneri: Financial Interests, Personal, Advisory Board: AstraZeneca, Daiichi Sankyo, Eisai, Eli Lilly, Exact Sciences, Gilead, Merck Serono, MSD, Novartis, Pfizer, Olema Oncology, Pierre Fabre; Financial Interests, Personal, Invited Speaker: AstraZeneca, Daiichi Sankyo, Eli Lilly, Exact Sciences, Gilead, GSK, Novartis, Roche, Zentiva; Financial Interests, Personal, Expert Testimony: Eli Lilly. All other authors have declared no conflicts of interest.