125I Seed Implant Brachytherapy for Painful Bone Metastases After Failure of External Beam Radiation Therapy

Abstract

The purpose of this study was to evaluate the safety and therapeutic efficacy of computed tomography (CT)-guided I seed implant brachytherapy in patients with painful metastatic bone lesions after failure of external beam radiation therapy (EBRT).From August 2012 to July 2014, 26 patients with painful bone metastases after failure of EBRT were treated with CT-guided I seed implant brachytherapy. Patient pain and analgesic use were measured using the Brief Pain Inventory before treatment, weekly for 4 weeks, and every 4 weeks thereafter for a total of 24 weeks. Opioid analgesic medications and complications were monitored at the same follow-up intervals.Before I seed implantation, the mean score for worst pain in a 24-hour period was 7.3 out of 10. Following treatment, at weeks 1, 4, 8, 12, and 24, worst pain decreased to 5.0 (P < 0.0001), 3.0 (P < 0.0001), 2.8 (P < 0.0001), 2.6 (P < 0.0001), and 2.0 (P = 0.0001), respectively. Opioid usage significantly decreased at weeks 4, 8, and 12. Overall response rates of osseous metastases after I seed implantation at 1, 4, 8, 12, and 24 weeks were 58%, 79%, 81%, 82%, and 80%, respectively. Adverse events were seen in 4 patients, including Grade 1 myelosuppression and Grade 1 late skin toxicity.I seed brachytherapy is a safe and effective treatment for patients with painful bone metastases after failure of EBRT.

FIGURE 1

(A) The inner green curve represent the PTV. The blue curve represent spinal cord. The red area is covered by 90% prescribed dose (108 Gy). Arrows point ureteral stents. (B) PET-CT scan before ¹²⁵I implantation treatment. (C) PET-CT scan at 5 months after treatment.

FIGURE 2

Summary box plots of BPI pain scores over time for patients treated with ¹²⁵I seed brachytherapy. (A) Worst pain. (B) Average pain. (C) Interference of pain in daily activities. (D) Pain relief from ¹²⁵I seed brachytherapy or medications.