Shear wave elastography detects novel imaging biomarkers of aromatase inhibitor–induced joint pain: A pilot study

Aim: To determine whether differences in joint and tendon stiffness as measured by ultrasound shear wave elastography are present in breast cancer patients with aromatase inhib-itor-associated arthralgias compared to age-comparable healthy control women. Methods: Postmenopausal women with stage I–III breast cancer who were taking adjuvant aromatase inhibitors and complained of joint pain were enrolled (n = 6). Postmenopausal women with no history of breast cancer, hormone treatment, or joint pain served as controls (n = 7). All subjects had bilateral hands and wrists evaluated by gray-scale and power Doppler ultra-sound, and shear wave elastography ultrasound. Results: Patients with AI-associated arthral-gias had significantly stiffer tendons than controls in the 1^st extensor compartment (long axis; p = 0.001), 4^th extensor compartment (long axis; p = 0.014), 3^rd metacarpophalangeal joint (p = 0.002), the pooled values of the extensor compartments, both long (p = 0.044) and short axes (p = 0.035), and the pooled values for the metacarpophalangeal joints (p = 0.002). On ultrasound, the patients (but not controls) presented with hyperemia and increased tenosyno-vial fluid in the flexor and extensor tendon sheaths, and the median nerves were symptomatic and bifid; however, these differences were not statistically significant. Conclusions: This is the first study to identify increased tendon stiffness as a putative physiological characteris-tic of aromatase inhibitor–associated arthralgias. Future studies should determine whether increased tendon stiffness is a risk factor for the development of aromatase inhibitor–associ-ated arthralgias, or a result of aromatase inhibitor treatment.