Pathologic fractures in patients with multiple myeloma undergoing bisphosphonate therapy: incidence and correlation with course of disease

OBJECTIVE: The purposes of this study were single-center analysis of the incidence of pathologic fractures in patients with multiple myeloma undergoing bisphosphonate therapy and correlation of the occurrence of pathologic fractures with the course of disease.

MATERIALS AND METHODS: One hundred ninety-one patients with multiple myeloma consecutively underwent unenhanced whole-body low-dose MDCT in parallel with hematologic follow-up. Only patients undergoing at least two whole-body low-dose MDCT examinations were included in this retrospective study, resulting in 561 survey intervals. The median analysis period per patient was 23 months (range, 3-53 months). Fracture incidence and the relation between newly occurring fractures and course of the disease were assessed.

RESULTS: Forty-nine pathologic fractures were detected in 49 of the 561 survey intervals (8.7%) and in 36 of the 191 patients (19%). Fractures were found on MDCT images irrespective of disease course. They were found in 25 of 202 intervals (12.4%) of progressive disease, in 14 of 171 intervals (8.2%) of disease remission, and in 10 of 188 intervals (5.3%) of stable disease. The overall calculated annual incidence of pathologic fractures in patients with multiple myeloma was 14%. Eleven patients had more than one fracture, all of which were vertebral compression fractures. Three patients had three episodes of bone fracture, and eight patients had two episodes.

CONCLUSION: Pathologic fractures in patients with multiple myeloma undergoing bisphosphonate therapy occur independently of myeloma activity and therefore should not be considered a sign of disease progression.