Similar recovery, shorter stay
Patients who received non-cryopreserved stem-cell grafts reached engraftment in the same median time as those who received cryopreserved grafts, and their estimated overall survival was comparable over three years. The non-cryopreserved group had shorter hospital stays, but mucositis was more common.
Researchers reviewed a retrospective, single-center cohort of 200 consecutive patients with multiple myeloma who underwent autologous transplantation, meaning the patients' own stem cells were used, between 2014 and 2024. Of them, 147 received non-cryopreserved grafts and 53 received cryopreserved grafts. The study was designed to compare safety, recovery of blood-forming cells, complications, time in hospital and long-term outcomes.
The comparison centered on the preservation method. Non-cryopreserved grafts were stored at 4°C and infused on day 0 after conditioning. Cryopreserved grafts used 10% DMSO, were frozen at −80°C, stored at approximately −190°C and thawed at 37°C before infusion on day 0.
The early outcomes
Median time to engraftment was 12 days in both groups. The middle half of patients reached that point between days 11 and 13 with non-cryopreserved grafts and between days 11 and 14 with cryopreserved grafts. The comparison did not show a statistically significant difference; the p-value was 0.062.
Hospitalization was shorter in the non-cryopreserved group. The median stay was 17 days, compared with 23.5 days for the cryopreserved group, a difference of 6.5 days. The reported p-value was below 0.001.
Inflammation of the mouth lining, known as mucositis, occurred in 45 of 147 non-cryopreserved patients, or 30.6%, compared with 6 of 53 cryopreserved patients, or 11.3%. The reported risk ratio, a comparison of the two rates, was 2.70, with a 95% confidence interval from 1.22 to 5.97 and a p-value of 0.006.
Infectious complications were not statistically different: 13 of 147 patients in the non-cryopreserved group, or 8.8%, compared with 7 of 53, or 13.2%, in the cryopreserved group. The p-value was 0.364. Deaths classified as transplant-related occurred in 3.4% of the non-cryopreserved group and 5.7% of the cryopreserved group, a difference that was also not statistically significant, with a p-value of 0.528.
The long-term picture needs care
Estimated overall survival was comparable at one, two and three years. In the non-cryopreserved group, the rates were 96.6%, 89.1% and 81.6%; in the cryopreserved group, they were 96.2%, 90.4% and 80.7%. The log-rank comparison found no statistically significant difference, with a p-value of 0.505.
Before adjustment, progression-free survival, the time patients remained alive without disease progression, was reported at 94.4%, 81.1% and 73.4% at one, two and three years in the non-cryopreserved group, compared with 92.3%, 84.6% and 63.0% in the cryopreserved group. The unadjusted log-rank comparison produced a p-value of 0.0329.
That result cannot be attributed to the storage method alone. The graft-preservation strategy was determined by institutional practice rather than random allocation, so differences between groups may reflect selection or changes in care over time. Non-cryopreserved use rose from 46.6% in 2014–2019 to 94.6% in 2020–2024. Recipients of non-cryopreserved grafts were older on average, 59 versus 56.5 years, and the groups also differed in induction treatment, CD34+ cell dose and pre-transplant response.
After adjustment for preservation method, CD34+ dose, pre-transplant response, age, transplant era, induction regimen and maintenance therapy, preservation method was not independently associated with progression-free survival. The adjusted hazard ratio for non-cryopreserved versus cryopreserved grafts, a comparison of progression-or-death rates over time, was 1.44, with a 95% confidence interval from 0.76 to 2.74 and a p-value of 0.262. The same model associated VGPR rather than CR with a higher progression-or-death hazard and maintenance therapy with a lower hazard; both p-values were 0.020.
What the study can and cannot answer
The evidence is limited by the design. This was a retrospective, single-center, non-randomized cohort, and the two groups were unequal in size. Preservation practice changed across the study period, leaving potential selection bias, temporal bias and confounding.
In this cohort, the two preservation strategies showed comparable engraftment, overall survival, infectious complications and transplant-related mortality, alongside a shorter observed hospital stay with non-cryopreserved grafts. The study did not establish that the preservation method caused the shorter stay, the mucositis difference or the unadjusted progression-free survival pattern.
The authors declared that no financial support was received for the work or its publication, and reported no commercial or financial relationships that could constitute a conflict of interest.
Paper data and sources
Original title: Comparison of non-cryopreserved and cryopreserved autologous hematopoietic stem cell transplantation among patients with myeloma: single-center experience
Authors: Chadievski L, Cvetanoski M, Genadieva Stavrikj S et al.
Journal/Repository: Frontiers in oncology
Status: Peer-reviewed
First online: 2026-10-09
DOI: Not available
Original paper · Full text