Aromatase inhibitor pain syndromes: Classification and determination of specific risk factors—A prospective multicenter cohort study.

Abstract

569 Background: Pain is frequent during Aromatase Inhibitors (AIs) treatment for breast cancer and several pain syndromes have been reported but not precisely defined. We developed a prospective multicentre study aiming at classifying AIs-related pain syndromes, comparing their impact on daily life, and identifying their specific determinants for a more targeted prevention approach. Methods: A one-year multicenter cohort prospective study, with 5 pre-scheduled visits, was carried out in early stage breast cancer women, free of pain, starting an AI treatment, recruited from 4 oncology centres. At baseline, clinical data (demography and psychosocial, cancer characteristics and treatments, pain, sleep, rheumatologic examination, cancer-related quality of life), biological data (sex hormones, vitamin D, bone biomarkers, oxidative stress, immunological and inflammatory markers), and genetic polymorphism for pain mechanisms (opioid and serotonin pathways) were recorded. Results: A cohort of 135 women was evaluated. Among them, 77 (57%) developed a pain syndrome along the study period, leading to AIs discontinuation in 12 cases. Five main different types of pain syndromes were identified: joint pain, in 48 women overall over the follow-up (36%), diffuse pain, in 30 women (22%), tendinitis, in 29 women (22%), and neuropathic pain, in 12 women (9%) and mixed types, which were frequent and often transient. Analyses demonstrated that risk factors for developing pain syndromes were baseline anxiety and impaired quality of life, while cancer features, genetic background, inflammation, immunological and sex hormone levels were not involved. Conclusions: In pain-free women with breast cancer starting an AI, risks for developing pain during the first year of treatment are slightly greater than 50%. We identified 5 main pain syndromes, joint and widespread pain being the most frequent. In all instances, initial psychological dimensions (personality, impaired quality of life and anxiety) are identified as major risk factors for pain development.