Pb2120 the Impact of Depth of Response Before and After Autologous Stem Cell Transplant for Multiple Myeloma Patients

Abstract

the spine and pelvic bones was carried out with a GE Signa Profile system without contrast enhancement 100 days after auto-HSCT. The nature of the lesions was determined and the bone marrow infiltration lesions (≥ 5 mm) counted. Statistical analysis was done using Statistica 10. Results: After auto-HSCT, the following antitumour response rates were observed: CR in 10 (72%), VGPR in 2 (14%) and PR in 2 subjects (14%). At 100 days after auto-HSCT all patients achieved strict CR (MRD-negativity according to flow cytometry). Focal changes in the bone marrow by MRI after auto-HSCT were detected in 12 patients: the minimum number of lesions was 1, the maximum was 40 (average 6). The distribution of patients according to the number of lesions after auto-HSCT was as follows: 0 -1 in 7 (50%) patients, 2 -40 in 7 (50%) cases. After auto-HSCT patients did not receive maintenance therapy they were monitored until the disease recurred. With a median follow-up of 21 months, relapse was documented among 8 patients. At the same time, in 3 of them, the results of MRI performed on the 100th day after auto-HSCT showed minimal bone marrow damage (less than 1 focus) and in 5 cases more than 1 lesion of the bone marrow was detected. 3-year PFS in the group of patients with minimal bone marrow damage on MR-tomograms (less than 1 lesion) was significantly (p < 0.05) higher and amounted to 52% versus 18% in the group of patients with more than 1 lesion detected in the bone marrow by MRI data (Figure 1). Summary/Conclusion: Differences in PFS suggest that in patients with MRD-negativity after auto-HSCT, a whole-body MRI reveals focal lesions in the bone marrow. Flow cytometry examines only local bone marrow damage from a biopsy. MRI of the bone marrow can reduce the false-negative results of the determination of MRD after auto-HSCT.