Incidence of arthralgia syndrome (AS) related to aromatase inhibitors (AIs) in postmenopausal women with early breast cancer (EBC)

Abstract

e11603 Background: Anastozole (A) and letrozole (L) are standard drugs in up-front adjuvant endocrine therapy in postmenopausal hormone positive EBC. AIs have a higher incidence of osteoporosis, bone fractures and musculoskeletal symptoms, particularly joint pain and stiffness (AS) respect to tamoxifen. The real incidence of AS can be underestimated respect to data derived from clinical trials. Methods: From 1/07 to 12/07 we registered all patients (pts) taking A or L as adjuvant therapy for at least 3 months. We screened 47 pts, 3 pts refused to participate at the study and 2 resulted metastatic. A total of 42 pts were enrolled. The median age was 67 yrs (range 51–89), the median time since menopause was 11 yrs (range 1–48). 30 pts had natural menopause, 7 surgical menopause and 5 reported chemo-induced menopause. 25 pts took A and 17 pts took L. The median duration on therapy was 19 months (range 3–68) and 31 pts had received chemotherapy (9 CMF, 17 anthra-based, 5 anthra-taxane based). Results: 11 pts (26%) did not report AS, 19 pts (45%) had new-onset AS and 12 (29%) had worsening of prior joint pain after starting adjuvant AIs therapy. Most pts reported moderate to severe AS requiring occasional use of nonsteroidal anti-inflammatory drugs (75%), 15% used oral supplements and 10% used opiates, only 4 women used exercise to relieve joint stiffness. 17 pts interrupted the therapy from 7 to 20 days in order to reduce the symptoms and 7 obtained a partial improvement. 11 pts (35%) suffered from AS declared the worsening of quality of life. In univariate analysis presence of AS was not associated with age, entry into menopause, years since menopause, duration of AI therapy or previous chemotherapy. Conclusions: Our data show a higher incidence of AS in clinical practice respect to literature data, which caused worsening of quality of life and could be reason of discontinuation of effective therapy. The exact mechanism of AIs-related arthralgia is unclear, but is believed to be related to estrogen deprivation, however further studies are needed to define the pathogenesis in order to find an effective therapy. No significant financial relationships to disclose.