Do Aromatase Inhibitor-Related AEs Affect Disease Prognosis?

Patients with postmenopausal estrogen receptor-positive breast cancer commonly receive five-year adjuvant treatment with aromatase inhibitors, although these are sometimes associated with adverse events (AEs) that affect a patient’s quality of life and can lead to treatment discontinuation. Some AEs associated with aromatase inhibitors include joint and vasomotor symptoms. A prospective cohort study explored how AEs affect prognosis in Japanese patients with postmenopausal breast cancer receiving adjuvant anastrozole, based on patient-reported outcomes (PROs). The findings of the study were presented at the San Antonio Breast Cancer Symposium.

The study included 391 patients from 28 centers. PRO assessments were conducted at baseline and three, six nine, and 12 months. Symptoms were classified as none (G0), mild (G1), moderate (G2), and severe (G3). Topics covered in the assessments included joint symptoms (arthralgia, decrease in range of joint motion, and joint stiffness), vasomotor symptoms (hot flashes, night sweats, and cold sweats), and adherence to anastrozole. Patients were followed for a median of 82 months.

Just more than half of patients (n=204; 52.2%) complete five-year treatment: 75 patients (19.2%) discontinued due to AEs (n=35), recurrence (n=19), secondary malignancies (n=4), non-breast cancer death (n=4), and other reasons (n=13). Forty-eight patients (12.3%) are currently receiving treatment, and 64 (16.4%) were unknown. Disease-free survival (DFS) was significantly better in patients with G2 and G3 joint symptoms than patients with G0 and G1 joint symptoms (five-year DFS, 96.1% vs. 83.3%; P=0.002). The same pattern was observed with vasomotor symptoms (five-year DFS, 93.5% vs. 86.3%, respectively; P=0.049). A slight association was observed between joint symptoms and overall survival (OS; P=0.062), but no correlation presented between vasomotor symptoms and OS.

“The DFS was superior in patients with G2 and G3 joint and vasomotor symptoms (five-year DFS, 100%), inferior in those with G0 and G1 joint and vasomotor symptoms (five-year DFS, 82.6%), and intermediate in others (five-year DFS, 93.3%; P=0.0024),” according to the researchers.

Multivariable analyses considering tumor size and grade found that G2 and G3 joint symptoms significantly and independently predicted DFS (hazard ratio, 0.298; 95% confidence interval, 0.122-0.621; P=0.0007).