Local irradiation prior to stem cell harvest has no influence on CD34+ yield: a quantitative analysis

Radiation Therapy Can Be Safely Incorporated into Pretransplantation Treatment Regimens for Patients with Multiple Myeloma

Primary treatment of multiple myeloma (MM) often involves systemic induction therapy (SIT) followed by autologous stem cell transplantation (ASCT). Radiation therapy (RT) is sometimes used for palliation; however, many practitioners avoid RT out of concern that future peripheral blood progenitor cell (PBPC) collection required for ASCT may be compromised. In this study, we retrospectively examined the possible effect of RT on PBPC collection. We reviewed the charts of 732 patients with MM treated with RT at our institution from 1999 to 2017, including patients who received RT prior to PBPC collection for planned ASCT. RT plans (both MM and non-MM RT) were reviewed to estimate the percentage of bone marrow (BM) treated using published estimates of skeletal BM distribution. Statistics were performed using Pearson correlation and the t-test. The 732 MM patients included 485 planned for ASCT; of these, 223 received RT prior to PBPC collection and were included in the final cohort. The median age at PBPC collection was 59 years (range, 33 to 80 years). For SIT, patients received combination regimens including the following agents: bortezomib (142 patients; 64%), lenalidomide (111 patients; 50%), and alkylators (46 patients; 21%). Nine patients (4%) received dexamethasone alone. The median cumulative %BM treated per patient was 6.7 (range .0 to 47.4). The median RT dose was 24 Gy (range, 10.0 to 75.6 Gy). Mobilization was performed using granulocyte-colony stimulating factor (G-CSF) alone (189 patients; 85%), G-CSF with plerixafor (15 patients; 7%), or chemotherapy (19 patients; 9%). A median of 7.8 × 106 CD34+/kg PBPCs (range, .5 to 54.8× 106 CD34+/kg) were collected in a median of 3 (range, 1 to 9) apheresis procedures. One hundred ninety-six patients (99%) collected ≥2.0 × 106 CD34+/kg PBPCs, and 166 (83%) collected >5.0 × 106 CD34+/kg PBPCs. The number of PBPCs collected was not associated with %BM treated (P = .15) or RT dose (P = .56). The number of apheresis procedures performed was not associated with %BM treated (P = .54) or RT dose (P = .85). The amount of PBPCs collected did not differ significantly between patients receiving RT to the pelvis/sacrum (P = .20) and those receiving RT to the spine (P = .13). The time to platelet engraftment was longer for patients with higher %BM treated (P = .02). Eleven patients did not undergo a confirmed ASCT, owing to patient preference (3 patients), trial therapy (1 patient), comorbidities (1 patient), election for hospice (1 patient), inadequate collection (4 patients), or inadequate follow-up (1 patient). In our study cohort, RT prior to ASCT did not impair successful ASCT. RT must be carefully planned and delivered to ensure safe incorporation into pre-ASCT treatment regimens.

Local Radiation Therapy Before and During Induction Delays Stem Cell Mobilization and Collection in Multiple Myeloma Patients

In multiple myeloma, local radiation therapy (RT) of osseous lesions before peripheral blood stem cell (PBSC) mobilization is assumed to impair the PBSC mobilization and collection. However, the results of previously published studies are inconsistent and do not evaluate detailed metrics of RT and PBSC outcome parameters. In total, 352 patients undergoing PBSC mobilizations and RT in first-line treatment were evaluated. Patients were grouped into RT (n = 283) and no RT (n = 69) before PBSC mobilization. Except for the International Staging System score, both groups were homogeneous regarding the first diagnosis characteristics, first-line treatments, and response parameters. RT metrics (RT yes versus no, volume of irradiated hematopoietic bone marrow [BM], biologically equivalent doses in 2 Gy fractions [EQD2]) were analyzed for the following PBSC outcome parameters: achievement of the PBSC collection goal, CD34+ cell collection yield, duration of the mobilization phase, and number of leukapheresis (LP) sessions to reach the collection goal. No statistically significant differences in the percentage of collection failures to reach at least 3 sufficient PBSC transplants were identified comparing patients with (n = 32 [11%]) and without RT (n = 4 [6%]) before PBSC mobilization (P = .265). However, patients with RT before PBSC mobilization showed a significant prolongation of the PBSC mobilization (median 1 day, P =.026) and required a higher number of LP sessions to reach the collection goal (median 1 LP, P < .001) compared with patients who received RT after PBSC mobilization. Moreover, patients with RT before PBSC mobilization reached a significantly lower CD34+ cell collection result (mean 8.94 versus 9.81 × 10⁶/kg body weight [bw], P = .002). No correlation was identified between the overall CD34+ cell yield and the volume of irradiated hematopoietic BM or EQD2, respectively. In the RT before PBSC mobilization group, patients who required more than 1 LP session to reach the PBSC collection goal after RT had a significantly higher percentage of radiated hematopoietic BM compared to those who required only 1 LP session (mean 9.7% versus 7.2%, P = .002). Overall, our study indicates a negative impact of RT on PBSC mobilization and collection. Apart from emergency settings, it might be beneficial to postpone RT to a post-PBSC collection time point. © 2021 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Current role of radiation therapy for multiple myeloma

Background: Radiation therapy (RT) is a treatment modality traditionally used in patients with multiple myeloma (MM), but little is known regarding the role and effectiveness of RT in the era of novel agents, i.e., immunomodulatory drugs and proteasome inhibitors.

Methods: We retrospectively reviewed data from 449 consecutive MM patients seen at our institute in 2010–2012 to assess indications for RT as well as its effectiveness. Pain response was scored similarly to RTOG 0631 and used the Numerical Rating Pain Scale.

Results: Among 442 evaluable patients, 149 (34%) patients and 262 sites received RT. The most common indication for RT was palliation of bone pain (n = 109, 42%), followed by prevention/treatment of pathological fractures (n = 73, 28%), spinal cord compression (n = 26, 10%), and involvement of vital organs/extramedullary disease (n = 25, 10%). Of the 55 patients evaluable for pain relief, complete and partial responses were obtained in 76.4 and 7.2%, respectively. Prior RT did not significantly decrease the median number of peripheral blood stem cells collected for autologous transplant, even when prior RT was given to both the spine and pelvis. Inadequacy of stem cell collection for autologous stem cell transplant (ASCT) was not significantly different and it occurred in 9 and 15% of patients receiving no RT and spine/pelvic RT, respectively. None of the three cases of therapy-induced acute myelogenous leukemia/MDS occurred in the RT group.

Conclusion: Despite the introduction of novel effective agents in the treatment of MM, RT remains a major therapeutic component for the management in 34% of patients, and it effectively provides pain relief while not interfering with successful peripheral blood stem cell collection for ASCT.

Risk factors for unsuccessful peripheral blood stem cell harvesting using granulocyte-colony stimulating factor mobilization in patients with multiple myeloma

The aim of this study was to determine factors that influence unsuccessful peripheral blood stem cell (PBSC) harvesting in patients with multiple myeloma (MM). Retrospective data of 186 MM patients who received G-CSF as mobilization were analyzed. Patients with successful harvest were compared with those who failed (using 2 definitions of failure <2 and <4 CD34 cells×10(6)/mm(3)). The groups were compared regarding age, gender, body weight, baseline platelet count, receipt of radiotherapy, number of prior chemotherapy regimens, PBSC count before collection, processed and collected volume, collect replace, number of sessions and final number of PBSC collected. By multivariate analysis, a baseline platelet count <161,000 cells/mm(3) was associated with PBSC harvest lower than 2×10(6)/kg, and age >58 years was related to PBSC harvest lower than 4×10(6)/kg CD34 cells/kg. Patients with these parameters should not receive mobilization protocols with G-CSF alone. Alternative protocols should be tested in this high risk harvest failure population.

Mobilisation strategies for normal and malignant cells

This review evaluates the latest information on the mobilisation of haemopoietic stem cells for transplantation, with the focus on what is the current best practice and how new understanding of the bone marrow stem cell niche provides new insights into optimising mobilisation regimens. The review then looks at the mobilisation of mesenchymal stromal cells, immune cells as well as malignant cells and what clinical implications there are.

Proposed definition of 'poor mobilizer' in lymphoma and multiple myeloma: an analytic hierarchy process by ad hoc working group Gruppo ItalianoTrapianto di Midollo Osseo

Many lymphoma and myeloma patients fail to undergo ASCT owing to poor mobilization. Identification of poor mobilizers (PMs) would provide a tool for early intervention with new mobilization agents. The Gruppo italianoTrapianto di Midollo Osseo working group proposed a definition of PMs applicable to clinical trials and clinical practice. The analytic hierarchy process, a method for group decision making, was used in setting prioritized criteria. Lymphoma or myeloma patients were defined as ‘proven PM' when: (1) after adequate mobilization (G-CSF 10 μg/kg if used alone or ⩾5 μg/kg after chemotherapy) circulating CD34⁺ cell peak is <20/μL up to 6 days after mobilization with G-CSF or up to 20 days after chemotherapy and G-CSF or (2) they yielded <2.0 × 10⁶ CD34⁺ cells per kg in ⩽3 apheresis. Patients were defined as predicted PMs if: (1) they failed a previous collection attempt (not otherwise specified); (2) they previously received extensive radiotherapy or full courses of therapy affecting SC mobilization; and (3) they met two of the following criteria: advanced disease (⩾2 lines of chemotherapy), refractory disease, extensive BM involvement or cellularity <30% at the time of mobilization; age ⩾65 years. This definition of proven and predicted PMs should be validated in clinical trials and common clinical practice.