Background Treatment with third generation aromatase inhibitors (AI) is associated with occurrence of arthralgia, with an incidence ranging from 25 to 45 %. In these patients, arthralgia may also be related to other conditions such as osteoarthritis, common tendinitis or auto immune diseases.

Objectives The aim of this study was to study patients treated with AI and reporting arthralgia, and comparing patients with new onset to patients with pre existing arthralgia and exacerbation under AI, to look for associated etiologic factors.

Methods Patients followed in a tertiary oncology center for breast cancer treated with AI and reporting arthralgia were prospectively screened for rheumatologic clinical evaluation, as well as biologic (ESR, CRP, RF, ANA, ACPA) or imaging (X-Rays of symptomatic regions) investigation. Type of cancer, duration, treatment, type of AI, duration of AI treatment. Patients were divided in two groups : patients with new onset of arthralgia under AI, and patients with pre existing and exacerbation of arthralgia under AI. The two groups are compared using t test for quantitative variables (significance : p less than 0.05).

Results Seventy five women were included, mean age (SD): 64.8 (9.2) years, time from cancer diagnosis : 34 (25) months. Adjuvant chemotherapy and/or radiotherapy were noted in respectively 52 and 64 cases. AI was Anastrozole (n = 6), Letrozole (55), Exemestane (14). Mean duration AI treatment since onset or exacerbation of arthralgia : 179 (224) days. Mean number of painful joints : 7.6 (9.7); locations (number of patients) :shoulder 36, elbow 22, wrist 25, MCP 27, PIP 26, knee 26, MTP28. Mean ESR : 29 (25)mm/h; CRP : 3 (7.6) mg/l). New onset arthralgia : n = 38; pre existing and exacerbation of arthralgia : n = 37. No statistical differences were found between these two groups for type of cancer, presence of chemotherapy or radiotherapy, presence of metastases, duration and type of AI treatment, VAS pain, number and distribution of tender joints, ESR, CRP, ANA, RF, ACPA positivity, and radiographic findings. Positive lymph nodes and radiographic signs of rotator cuff dysfunction were statistically more frequent in the pre existing and exacerbation group. Some specific diagnoses were done after evaluation : 2 CREST syndrome (one in each group), 1 RA and 1 Sjögren syndrome in the new onset symptom group.

Conclusions Arthralgia under AI treatment is frequent. Our study argues for an absence of specificity of these arthralgia, without particular difference between new onset or exacerbation of pre existing arthralgia, auto immune disease seem more frequent in the new onset symptom group, and thus possibly related to anti aromatase therapy.

Disclosure of Interest None Declared