Lee, S., & Chun, M. (2012). Pain relief by Cyberknife radiosurgery for spinal metastasis. Tumori, 98, 238–242. 

To describe pain relief in patients with spinal metastasis treated with the CyberKnife^® Robotic Radiosurgery System, and to analyze the factors associated with a relapse in pain after pain relief

Radiosurgery was performed using CyberKnife^®, a unique, image-guided, frameless stereotactic radiosurgery delivery system. The CyberKnife^® is a lightweight 6-MV linear accelerator (LINAC) attached to the end of a robotic arm with six axes of freedom. An MRI or PET-CT scan was obtained of all patients prior to treatment to evaluate the extent of spinal lesions, and the MRI was fused with a planning CT to better contour the target volume. An appropriate immobilization device was used to treat patients in the supine position. The clinical target volume (CTV) and the planning target volume (PTV) were the same, a 1–2 mm margin around the gross tumor volume. The delivered dose was kept at less than 13 Gy in a single fraction and less than 21.4 Gy in three fractions. The total dose of radiation delivered to the spinal cord was 15–35 Gy in one to five fractions. Pain was measured before radiosurgery, “soon after” radiosurgery, and then every one to three months (last measurement was done by telephone). Analgesic use was measured before and after treatment.

• N = 57
• AGE: Not reported 
• MALES: 54%, FEMALES: 46%
• KEY DISEASE CHARACTERISTICS: All patients had one or more spinal lesions related to metastatic cancer. Primary tumors included breast, liver, lung, cervix, colorectum, biliary tract, stomach, prostate, and others. 
• OTHER KEY SAMPLE CHARACTERISTICS: Seventy percent of the lesions caused moderate to severe pain before radiosurgery (six lesions did not cause pain). All patients were on opioid analgesics. Fourteen patients had received previous external beam radiotherapy for their spinal lesions; the median duration between radiosurgery and prior radiotherapy was 10 months. Three patients had a previous laminectomy or corpectomy and were then receiving radiosurgery for disease progression.

• SITE: Not stated/unknown  
• SETTING TYPE: Outpatient  
• LOCATION: Although not explicitly stated, it is assumed that the study was conducted in Korea at either the department of radiation oncology at Konyang University or Ajou University or both.

• PHASE OF CARE: Mutliple phases of care
• APPLICATIONS: Palliative care 

Retrospective pre/post design

Pain was measured using a 0–10 Visual Analog Scale (VAS). Pain relief was considered a reduction in the pain score by three levels, and pain progression was considered an increase in the pain score by three levels. No use of analgesics or a score of 0 or 1 was considered complete relief. The latency to pain relief was calculated beginning from the first day of radiosurgery. The duration of pain relief was measured from the first day of pain relief to the time of pain progression or until the last follow-up. Analgesic use was recorded before and after treatment.

Pain relief was obtained in 88% of the painful lesions (59 of 67 lesions), and complete relief was obtained in 51% (34 of 67 lesions). No radiation-induced myelopathy occurred. Those patients (n = 6) who did not have painful lesions prior to radiosurgery remained pain-free without disease progression. For the majority of patients who received pain relief from treatment, pain relief was obtained within seven days of beginning radiosurgery. The median duration of pain relief was 3.2 months (range = 1–30 months). Factors associated with pain relapse were the presence of spinal cord compression (p = 0.001) and an Eastern Cooperative Oncology Group (ECOG) performance status of ≥ 2 (0 = 0.01).

Although the sample size was small, this study found similar results as previous studies examining the use of spinal radiosurgery for pain relief. CyberKnife^® is an effective method for treating pain related to spinal metastasis. Long-term follow-up of patients treated with spinal radiosurgery is needed to determine the duration of pain relief and any long-term effects related to treatment.

• Small sample (< 100)
• Risk of bias (no control group)
• Risk of bias (no blinding): No blinding of those reviewing radiological records; no blinding of patients  
• Risk of bias (no random assignment): Not a randomized, controlled trial; retrospective review, so there is a risk of bias
• Risk of bias (no appropriate attentional control condition)  
• Findings not generalizable: Not a randomized, controlled trial; findings similar to other studies
• Other limitations/explanation: Patient demographics not reported; difficult to generalize

The use of spinal radiosurgery in treating pain related to metastatic cancer is an important palliative care treatment for pain relief as patients tolerate it well and there appear to be no side effects. Although CyberKnife^® treatment is not available at all hospitals and medical centers, nurses should be aware of this effective pain relief intervention.