Aromatase inhibitor-induced joint symptom in patients with breast cancer

11070 Background: Aromatase inhibitor (AI) are superior to tamoxifen (TAM) for postmenopausal women with estrogen receptor (ER)-positive breast cancer. Toxic profiles are different between AI and TAM. The frequency of bone fracture and joint symptom are high in AI compared with TAM. However, there is little report concerning a detailed joint symptom. Methods: From January 2002 to March 2006, 120 postmenopausal women with ER-positive breast cancer were treated with anastrozole 1mg or exemestane 25mg daily at our hospital. We studied retrospectively the incidence, onset, type, sites, grade, and change of joint symptom. We also investigated the incidence of discontinuation due to joint symptoms and correlation between patient’s characteristics and joint symptoms. Results: Median follow-up time is 590 days and median age is 63 years old. Forty-seven (39.1%) of 120 patients complained of joint symptom. Median onset time of the symptom was 90 days of starting AI. All cases with the symptom complained of joint stiffness and 33 (70.2%) of 47 patients with the symptom have joint pain. In decreasing order, the most commonly affected sites were hand, knee, wrist, ankle, shoulder and elbow. The joint symptom was mostly grade 1/2, and most symptom ware resolved with exercise. Most common feature is morning digital stiffness like initial symptom of rheumatoid arthritis. Some patients experienced severe joint symptom. Subsequently, 15 (12.5%) patients had to discontinue AI because of the severe symptom. Discontinuation of AI led to improvement of symptoms, and patients received TAM in stead of AI also led to resolution of symptoms. AI-induced joint symptom was significantly correlated with young age, prior chemotherapy and switching from TAM to AI. Conclusions: Most AI-induced joint symptom is modest, and this symptom can lead to resolution with exercise. However, some patients lead to discontinue AI because of AI-induced severe joint symptom. We should inform patients treated with AI about AI- induced joint symptom and observe patient’s symptom in detail because severe joint symptom can prevent maintenance of quality of life and compliance. No significant financial relationships to disclose.