Identifying factors associated with falls in postmenopausal breast cancer survivors: a multi-disciplinary approach.

OBJECTIVE To identify neuromuscular, balance, and vision factors that contribute to falls in recently treated breast cancer survivors (BCS) and explore links between fall risk factors and cancer treatment. DESIGN Case-control plus prospective observation. SETTING Comprehensive cancer center. PARTICIPANTS BCS (N=59; mean age, 58y) within 2 years of chemotherapy completion and/or on adjuvant endocrine therapy. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Objective measures of postural control, vision, and neuromuscular function included: (1) a sensory organization test (SOT), (2) a visual assessment battery, (3) muscle mass by dual energy x-ray absorptiometry, and (4) neuromuscular function with strength by repetition maximum, power by timed stair climb, and gait speed by 4m walk. Falls were self-reported for the past year (retrospective) and monthly for 6 months (prospective). RESULTS Fifty eight percent of BCS reported falls in the past year. BCS with a history of falls had lower SOT scores with a vestibular deficit pattern in postural control (P<.01) and took longer to read letters on the contrast sensitivity chart (P<.05). Vestibular score on the SOT mediated the relationship between treatment and falls among BCS who received chemotherapy only, but not adjuvant endocrine therapy. CONCLUSIONS Results of this project suggest that balance disturbances of vestibular origin and delays in detecting low contrast visual stimuli are associated with falls in BCS. Future studies that track falls and fall risk factors in BCS from diagnosis through treatment are warranted, as are studies that can identify treatment-related vestibular dysfunction and altered visual processing.