Using focal lesions seen on PET-CT to monitor outcome in multiple myeloma

This study examined the use of PET-CT imaging to monitor response to treatment for multiple myeloma. The study concluded that treatment to suppress focal lesions seen on PET-CT is an important goal for newly diagnosed patients.

One way to improve outcomes in multiple myeloma is to customize treatment based on the response to therapy. One technique used is fluorine-18 fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET-CT). FDG PET-CT works by taking multiple images of the body and measuring cell activity. It can identify focal lesions, which are lesions seen when myeloma grows. PET-CT is useful as it can detect a rapid response to treatment. A previous study found that use of PET-CT to monitor lesions can help with prognosis.

596 patients with multiple myeloma who had PET-CT performed were studied. Patients were followed-up for an average 5.1 years. At 3 years, the average survival was 82%. At diagnosis, 62% of patients had focal lesions detected.

Having more than 3 focal lesions detected at the start of the study was associated with worse overall survival. There was no difference in survival between those patients with 0 focal lesions and those with 1-3 focal lesions.

The suppression of focal lesions following treatment was found to predict outcome. Patients who had complete suppression of focal lesions after treatment had similar survival as those who had no focal lesions at the start. Survival without worsening disease was also similar between those who had suppression of focal lesions and those with no focal lesions from the start. 

The authors concluded that suppression of focal lesions seen on PET-CT was an important goal, and that patients with undetectable lesions had similar outcomes as those without lesions at the start of the study.