HER2DXを活用した高齢者HER2陽性早期乳癌における多遺伝子解析研究 (Trans-RESPECT)

私はもともと癌診療に興味があり、その中で研修病院（名古屋医療センター）で腫瘍内科の先生方の働きをみて、腫瘍内科医を目指すことになりました。臓器横断的にがん診療をすることの面白さ、臨床試験を通して実践する新しい治療の強く惹かれました。

JSMOは海外を感じられる素晴らしい会です。私もJSMO2024をきっかけに海外オンコロジストとの繋がりができました。

HER2DX Analysis in Older Patients with HER2+ Early Breast Cancer from Phase 3 RESPECT Trial

[Background]

HER2DX, the first multigene assay designed for HER2+ breast cancer, has demonstrated potential to guide treatment decisions. However, its validation in the context of de-escalated chemotherapy regimens in older patients remains limited. We assessed the prognostic and potential predictive value of HER2DX within the phase 3 RESPECT trial (NCT01104935).

[Methods]

This was a prespecified translational analysis evaluating the HER2DX risk score and pathologic complete response (pCR) likelihood score. Participants were randomized to receive trastuzumab monotherapy (H group) or trastuzumab plus chemotherapy (H+CT group). Risk stratification into HER2DX low- or high-risk groups used the standard 50 cutoff (scale 1-99). The primary endpoint was relapse-free survival (RFS), with secondary endpoints including overall survival (OS).

[Results]

Among 275 patients in the RESPECT trial, 154 tumors (56.0%) were profiled using HER2DX (H group: 74; H+CT group: 80). The median follow-up was 9.3 years. Most patients (92.9%) had a performance status of 0, 28.6% were older than 75 years, 53.2% were HR-negative, 80.5% had node-negative disease, and the majority had pT2 (44.8%) tumors. Using the HER2DX 50 cutoff, 40 patients (26.0%) were classified as high risk, and 114 (74.0%) as low risk. RFS was higher in the HER2DX low-risk group compared to the high-risk group (hazard ratio [HR]=2.02, 95% CI: