Maximizing the Clinical Benefit of Radiotherapy in Solitary Plasmacytoma: An International Multicenter Analysis

Abstract

Objective: Although local definitive radiotherapy (RT) is considered the standard of care for solitary plasmacytoma (SP), the optimal RT parameters for SP patients have not been defined. The aim of this retrospective study is to analyze the effectiveness of various RT doses, volumes, and techniques, as well as to define the relevant prognostic factors in SP. Methods: Between 2000 and 2019, 84 patients, including 54 with solitary bone plasmacytoma (SBP) and 30 with extramedullary plasmacytoma (EMP), underwent RT at six institutions. Results: The overall RT median dose was 42 Gy (range, 36.0–59.4). The median follow-up period was 46 months. Overall, the local control (LC) rate was 96%, while the complete remission (CR) rate was 46%. The 5-year local relapse-free survival (LRFS), multiple myeloma-free survival (MMFS), progression-free survival (PFS), and overall survival (OS) rates were 89%, 71%, 55%, and 93%, respectively. Using an RT dose above 40 Gy was associated with a higher complete remission (CR) rate and a lower rate of local relapse. Modern irradiation techniques were associated with a trend toward a higher LC rate (98% vs. 87% for conventional, p = 0.09) and a significantly lower local relapse rate (6% vs. 25% for conventional, p = 0.04). However, RT dose escalation and technique did not lead to a significant effect on MMFS, PFS, and OS. Univariate analyses identified several patient characteristics as potentially relevant prognostic factors. In SBP patients, systemic therapy administration was associated significantly with MMFS and PFS rates. Conclusion: Using an RT dose >40 Gy and modern RT techniques may improve the local control and reduce the rate of relapse, without a significant impact on survival rates. The addition of systemic therapies may improve the MMFS and PFS rates of SBP patients.

Esophageal Plasmacytoma Revealed by Persistent Hiccups: A Case Report and Literature Review

“…The dose used for our patient was 40 Gy as recommended by the International Lymphoma Radiation Oncology Group. Interestingly, Elsayad et al have shown in their international multicenter analysis that using radiotherapy dose-escalation (above 40 Gy) and modern irradiation techniques as intensity-modulated radiotherapy (IMRT) and proton therapy seem to improve the local control and reduce the rate of relapse in patients with solitary bone or solitary extramedullary plasmacytoma, without a significant effect on survival rates [ 12 ]. Imaging examinations, such as positron emission tomography (PET) computed tomography (CT), are required for the management of suspected SEP, as well as to monitor the therapeutic response to radiotherapy and the possibility of recurrence and progression of into multiple myeloma [ 13 ].…”

Surgery Results in Low Relapse and Progression Rates in Extramedullary Plasmacytoma of the Head and Neck: A Case Cohort and Review of the Literature

“… 21 In the study by Elsayad including 84 patients with solitary plasmacytoma (including 30 patients with EMP) the addition of systemic therapy improved MM free survival and PFS. 9 Only 4 patients with EMP received systemic therapy thereby rendering a conclusion in EMP patients impossible. The study by Mignot included 46 patients with solitary plasmacytoma (including 6 EMP) treated by either radiotherapy alone or concomitant radiotherapy and systemic therapy with 4 cycles of lenalidomide and dexamethasone.…”

“…EMP is highly radiosensitive, and radiation doses above 40-45 Gy are associated with improved survival as compared to lower doses. 2,4,[6][7][8][9] Some centers prefer radiation therapy because of the mutilating procedure of curative surgery. While some studies suggest the benefit of radiation, others show better survival for patients after radical surgery without additional radiation.…”

Spatial Distribution of Focal Lesions in Whole-Body MRI and Influence of MRI Protocol on Staging in Patients with Smoldering Multiple Myeloma According to the New SLiM-CRAB-Criteria

“…Patients with earlier treatment due to localized plasma cell tumor plus evidence of systemic disease were excluded, as these patients are considered to have distinct progression risks. Furthermore, not all of these patients with local plasma cell tumors had received radiotherapy with a dose of more than 40 Gy, which has been shown to be the preferable dose in order to receive complete local remission by a recent study [ 14 ]. This resulted in a baseline-cohort of 147 patients with MRI at initial diagnosis, 52 of which received follow-up wb-MRI and are referred to as follow-up cohort.…”