Background Malignant lumbosacral plexopathy is caused by a direct extension of an intrapelvic malignancy to involve the plexus nerves. In this report, we describe the effect of radiotherapy on patients with malignant lumbosacral plexopathy. Patients and methods We performed a retrospective review of the medical records of patients who underwent radiation therapy for pain caused by malignant lumbosacral plexopathy between 2017 and 2020 at our institution. The pain was measured using a numeric rating scale (0-10) at initiation and completion of radiotherapy or at the time when the maximum response was observed. Results A total of 12 tumor sites in 11 patients were included. Eight of the tumors invaded the iliopsoas muscle, and the remaining four invaded or abutted the piriformis muscle. The mean duration of follow-up was 215 days (31-675 days). All patients achieved pain relief at the end of radiotherapy, with complete resolution of pain in nine patients. The maximum effect was seen at a mean of three weeks (1-12 weeks) after the initiation of radiotherapy. Toxicities related to radiotherapy included grade 1 diarrhea in four patients and grade 1 frequent urination in one patient. Two patients experienced a relapse of pain at one and two months, respectively, after achieving their maximal response. Conclusion Radiotherapy provides significant pain relief for patients with the malignant lumbosacral syndrome. The recognition and diagnosis of this syndrome, and the use of radiation therapy as a therapeutic option, are important. Patients should be offered all possible therapies, regardless of curative or palliative intent.
Keywords: malignant lumbosacral plexopathy; malignant psoas syndrome; pain management; palliative care; radiation therapy.
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