Phase II Multi-Institutional Study of Low-Dose (2 Gy x 2) Palliative Radiotherapy for Symptomatic Bone Metastases From Multiple Myeloma

ABSTRACT

Purpose/Objective(s) Painful osteolytic bone lesions are common in patients with multiple myeloma (MM). Radiotherapy (RT) is effective in providing pain relief from MM bone lesions in over 80% of patients. There is no consensus as to the most effective dose or fractionation for palliation. Shorter courses of RT are not only more convenient for patients and their families, but they also have less impact on timing of systemic therapies. There is precedent for using 2 Gy x 2 for palliation of lymphomas, which have similar radiosensitivity to myeloma. The primary objective is to determine whether treatment with 2 Gy x 2 to painful myeloma bone lesions achieves patient-reported pain reduction comparable to historical controls at 4 weeks. Secondary objectives will assess QOL endpoints, use of analgesia and time to pain relief, and duration of pain relief. Materials/Methods: Patients who consent to participation will complete quality of life and pain questionnaires (Brief Pain Index, EORTC QLQ-BM22, and EORTC QLQ-C30) prior to treatment and at 2,4,8 weeks and 6 months following treatment. Pain response, as defined by the international consensus on palliative RT for bone metastases, will be measured based on BPI and daily oral morphine equivalent. Reirradiation at standard dose can be considered at ≥4 weeks following initial treatment for indeterminate pain response or pain progression. Cytogenetics and International Myeloma Working Group risk stratification and response criteria are recorded, when available, but are not required for patient participation. Results: This trial, supported by ILROG, has opened at 7 institutions with one more in process of opening. Prior to COVID, accrual was 1.5 patients per month. Since COVID, enrollment has been at 0.7 patients per month. A total of 18 patients have been accrued. The median age of patients accrued is 65.5 years with 7/18 female patients. Fourteen patients are Caucasian. Twelve patients have an ECOG performance score of 1-2. Thirteen patients had pain response captured at 4 weeks following RT. Of the 5 patients that did not complete questionnaires at 4 weeks post-RT, 2 expired, 1 was lost to follow-up, 1 had a missed evaluation and 1 had pain progression). The most common site of treatment was the shoulder (4/18). Conclusion: This ongoing prospective trial in palliation of multiple myeloma bone lesions is feasible and able to accrue at multiple institutions and will provide valuable information as to the role of low-dose RT in this population.