Study Favors PET-CT Scans Over Whole-Body MRI In Determining Response To Myeloma Treatment

Results of a recent German study suggest that PET-CT scans may be more reliable than whole-body MRI in determining the remission status of multiple myeloma patients after stem cell transplantation.
The investigators conclude that both PET-CT and whole-body MRI provide useful information about a patient’s disease status. However, MRI often incorrectly detects activity in bone lesions that persist after treatment. They therefore state that PET-CT may be better than MRI for determining remission status.
Similar results were found in a recent Italian study that compared PET-CT and MRI for the evaluation of multiple myeloma at different stages of the disease. This study found that MRI was more accurate than PET-CT for staging newly diagnosed patients and identifying those with recurring disease. However, the study showed that PET-CT was more reliable than MRI for evaluating a patient's response to therapy (see related Beacon news).
To follow-up on the results of the current German study, the investigators recommend additional prospective studies with a larger number of patients. They also suggest evaluating the performance of PET-MRI for the detection of bone lesions in myeloma patients, which would combine the strengths of both imaging techniques.
Previous studies have shown that both PET-CT and MRI are superior to x-rays for the detection of myeloma-related bone lesions (see related Beacon news).
Currently, a myeloma patient's remission status is based on blood-related measurements. The additional information provided by newer imaging techniques could be used to guide further treatment.
PET-CT combines positron emission tomography (PET) and computerized tomography (CT).
Prior to a PET scan, patients are injected with a radioactive molecule called FDG, which accumulates in cancer cells. The scan then detects cancerous areas based on radioactivity levels.
By conducting a PET scan together with a CT scan, which constructs a three-dimensional image of the body from a series of x-rays, the precise location of the cancer cells can be determined.
Magnetic resonance imaging (MRI) is a medical imaging technique used to generate detailed images of bones, organs, and soft tissue. Images obtained from an MRI allow physicians to detect bone lesions in myeloma patients.
In the current study, German researchers retrospectively compared the performance of PET-CT and whole-body MRI in determining the remission status of myeloma patients after stem cell transplantation.
Overall, 31 patients who received a stem cell transplant were examined with both PET-CT and MRI. The average age of the patients was 55 years, and all patients underwent a standard evaluation to determine disease status. This evaluation included whole blood count; blood levels of protein, beta-2-microglobulin, C-reactive protein, and free light chains; immunofixation analysis; and bone marrow biopsy or aspiration when appropriate.
The average time interval between a patient's last stem cell transplant and post-transplant imaging was 3.1 years, with a range of 2 months to 11.9 years.
Prior to the PET-CT and MRI scans, 77 percent of the patients had received a donor stem cell transplant and 23 percent had received an autologous stem cell transplant.
At the time of imaging, 68 percent were in complete remission, 16 percent had a very good partial response, and 16 percent had a partial response, according to standard methods.
PET-CT scans accurately determined the remission status of 74 percent of the patients, and there was a significant correlation between diagnostic results determined by PET-CT and standard methods.
However, MRI accurately determined the remission status of 52 percent of patients, and there was no correlation between the remission statuses obtained from MRI and standard methods.
PET-CT detected a total of 12 lesions in 9 out of the 31 patients. Whole-body MRI, on the other hand, detected 104 lesions in 21 patients. All of the lesions detected by PET-CT were also detected by MRI.
PET-CT incorrectly detected lesions in 14 percent of the patients in complete remission and failed to detect lesions in 50 percent of the patients with a partial or very good partial response.
In comparison, MRI incorrectly detected a total of 63 lesions in 62 percent of the patients in complete remission and failed to detect lesions in 20 percent of the patients with a partial or very good partial response.
For more information, please see the study in European Radiology (abstract).
Related Articles:
- Sustained Complete Response To Initial Treatment Associated With Substantial Survival Benefit In Multiple Myeloma
- Stem Cell Transplantation May Be Underutilized In Multiple Myeloma Patients In Their 80s
- Revlimid, Velcade, and Dexamethasone, Followed By Stem Cell Transplantation, Yields Deep Responses And Considerable Overall Survival In Newly Diagnosed Multiple Myeloma
- Early Use Of Radiation Therapy Associated With Shorter Survival In Multiple Myeloma
- Nelfinavir-Velcade Combination Very Active In Advanced, Velcade-Resistant Multiple Myeloma