Carpal tunnel syndrome and tenosynovitis in women with breast cancer associated with hormone therapy: A multi-institutional analysis using a clinical data warehouse.

The study aims to evaluate the characteristics, treatments, and incidence rates of carpal tunnel syndrome (CTS) and tenosynovitis in women with breast cancer, according to the hormone therapy used. We retrospectively reviewed women with breast cancer identified from the clinical data warehouse of the six hospitals in Korea, from January 2015 to August 2020. Among them, patients with CTS or tenosynovitis were reviewed in terms of disease status and treatments. A total of 101 patients among a population of 15,504 met the study inclusion criteria, so their clinical data were analyzed. Aromatase inhibitor (AI) users frequently needed oral medication for CTS, and developed severe CTS which frequently required surgery. AI users presented with a higher incidence of CTS (1.3%) than patients without hormone therapy (0.4%), and tenosynovitis occurred at a higher rate in AI users (2.3%) compared to the tamoxifen (1.1%) and no hormone groups (0.5%). More than half of the CTS and tenosynovitis occurred within 12 months after hormone commencement. The incidence and disease characteristics of CTS and tenosynovitis differed among the groups depending on the type of hormone therapy received. Our findings will help clinicians understand clinical courses and treatments for CTS and tenosynovitis in breast cancer patients.