Mid-term efficacy grading evaluation and predictive factors of magnetic resonance-guided focused ultrasound surgery for painful bone metastases: a multi-center study

OBJECTIVES

MR imaging-guided focused ultrasound surgery (MRgFUS) is an emerging non-invasive treatment. It is helpful in investigating the mid-term grading efficacy and safety of MRgFUS, and possible risk factors in participants with painful bone metastases.

METHODS

This four-center prospective study enrolled 96 participants between June 2016 and May 2019 with painful bone metastases. The Numerical Rating Scale (NRS), Brief Pain Inventory-Quality of Life (BPI-QoL) score, morphine equivalent daily dose (MEDD), and the adverse events (AEs) were recorded before and at 1 week, 1 month, 2 months, and 3 months after MRgFUS. The repeated ANOVA tests were used to analyze the change in NRS and BPI-QoL, and logistic regression analysis was used to analyze the possible risk factors.

RESULTS

A total of 82 participants completed the 3-month follow-up period. And 16 (19.5%) participants were complete responders (CR), 46 (56.1%) participants were effective responders (ER), and the other 20 (24.4%) participants were non-responders (NR). The NRS (2.67 ± 2.47 at 3 months compared to 6.38 ± 1.70 before treatment) and BPI-QoL score (3.11 ± 2.51 at 3 months compared to 5.40 ± 1.85 before treatment) significantly decreased after the treatment at all time points (p < 0.001). Eleven adverse events were recorded and they were all cured within 1 to 52 days after treatment. The non-perfused volume (NPV) ratio (p = 0.001) and the bone metastases lesion type (p = 0.025) were the key risk factors.

CONCLUSIONS

MRgFUS can be used as a non-invasive, effective, and safe modality to treat painful bone metastases. NPV ratio and the lesion type may be used as affecting factors to predict the mid-term efficacy of MRgFUS.

KEY POINTS

• MRgFUS can be considered a non-invasive, effective, and safe modality to treat painful bone metastases. • The NRS and BPI-QoL score at 1 week, 1 month, 2 months, and 3 months all decreased significantly (p < 0.001) after receiving MRgFUS. Among 82 participants, 16 (19.5%) were complete responders, 46 (56.1%) were effective responders, and the other 20 (24.4%) were non-responders. • According to logistic regression analysis, non-perfused volume ratio and the bone metastases lesion type were the affecting factors to predict the mid-term efficacy of MRgFUS. The adjusted OR of non-perfused volume ratio was 0.86 (p = 0.001), and osteoblastic lesion type was 0.06 (p = 0.025).

Protocol for a confirmatory trial of the effectiveness and safety of palliative arterial embolization for painful bone metastases

BACKGROUND

Transcatheter arterial embolization (TAE) has long been used for hemostasis of traumatic or postoperative hemorrhage and embolization of tumors. Previous retrospective studies of TAE for painful bone metastases showed 60%-80% pain reduction with a median time to response of 1-2 days. Compared with radiotherapy and bisphosphonates, time to response appeared earlier than that of radiotherapy or bone-modifying agents. However, few prospective studies have examined TAE for this indication. Here, we describe the protocol for a confirmatory study designed to clarify the efficacy and safety profile of TAE.

METHODS

This study will be a multicenter, single-arm confirmatory study (phase 2-3 design). Patients with painful bone metastases from any primary tumor are eligible for enrollment. TAE will be the main intervention. Following puncture of the femoral artery under local anesthesia and insertion of an angiographic sheath, angiography will confirm that the injected region includes tumor vasculature. Catheter position will be adjusted so that the embolization range does not include non-target tissues. Spherical embolic material will then be slowly injected into the artery to embolize it. The primary endpoint (efficacy) is the proportion of subjects with pain relief at 72 h after TAE and the secondary endpoint (safety) is the incidence of all NCI Common Terminology Criteria for Adverse Events version 5.0 Grade 4 adverse events and Grade ≥ 3 necrosis of the central nervous system.

DISCUSSION

If the primary and secondary endpoints are met, TAE can be a treatment choice for painful bone metastases. Trial registry number is UMIN-CTR ID: UMIN000040794.

TRIAL REGISTRATION

The study is ongoing, and patients are currently being enrolled. Enrollment started in March 2021. A total of 36 patients have participated as of Aug 2022.

PROTOCOL VERSION

Ver1.4, 13/07/2022.

Palliative radiotherapy for painful bone metastases from solid tumors delivered with static ports of tomotherapy (TomoDirect): feasibility and clinical results

PURPOSE

To evaluate the feasibility and response to palliative radiotherapy delivered with static ports of tomotherapy--TomoDirect (TD) in patients affected with painful bone metastases from solid tumors.

METHODS

A prospective cohort of 130 patients (185 osseous lesions) was treated between 2010 and 2013 with TD. Three fractionation schedules were employed according to clinical decision-making (3 Gy × 10; 4 Gy × 5; 8 Gy × 1). Pain response was investigated at 2 weeks and 2 months (for evaluable patients). The Numeric Rating Scale (NRS-11) was used to assess pain. Response rates to radiotherapy were calculated following the criteria of the International Bone Metastases Consensus Group (IBMCG), accounting for the use of concomitant analgesics (response: complete or partial; non-response: stable pain, pain progression or "other"). Analgesic consumption was recalculated into the daily oral morphine-equivalent dose (OMED).

RESULTS

Most of the patients had 1-2 bone metastases (91); those with multiple lesions mostly had a metachronous presentation (60%). Synchronous lesions were mainly approached with multiple plans (63%). Most treatments employed 3-4 fields (77%). Treatment times ranged from 255 to 939 s depending on fractionation, fields, and target lesions number. At 2 weeks, the median self-reported worst pain decreased significantly as median oral morphine-equivalent dose regardless of fractionation used. The response rate according to the IBMCG-based response categories ranged from 45 to 55%. Pain relief duration seems (response at 2 months) slightly inferior with the single fraction approach, with a higher re-treatment rate. At 2 weeks, the median self-reported worst pain and OMED significantly decreased regardless of fractionation (response rate: 49-55%). Pain relief decreased at 2 months, especially for single fraction (higher re-treatment rate).

CONCLUSION

TD is a valid option to deliver palliative radiotherapy for painful bone metastases from solid tumors.