Whole Versus Partial Vertebral Body IMRT for Spinal Metastases

This study is a prospective, randomized, single center, controlled explorative study in the parallel-group design to evaluate the difference in clinical outcomes for patients with metastatic spine disease treated with a whole versus partial vertebral body contouring approach. Thereby two different techniques were evaluated: whole vertebral body (WB) group with 10 x 3Gy or partial vertebral body (PB) group with 10x (3-5)Gy. Prior to their enrolment into the study, the patients will undergo a staging of the vertebral column in connection with their radiation-planning computed tomography (CT) and MRI to measure the myelon dimension. After the baseline results have been recorded, the patients will be randomized into one of the two groups: PB group RT 10x (3-5) Gy (n = 30) or WB group RT 10 x 3 Gy (n = 30). The target parameters will be measured and recorded at baseline, at 1 to 2 weeks; and at months 2 to 3, 4 to 6 and 7 to 12 after treatment.

The primary endpoint was the time to pain relief. Secondary endpoints were quality of life (QoL), fatigue, pain, overall survival, bone survival, local control, pathological fracture, pain-free internal and neurological deficit. The baseline examination shall be carried out on the first day of radiotherapy prior to the start of therapy and is scheduled to comprise the comprehensive recording of the sociodemographic data, the recording of the current pain situation, the quality of life, and the current degree of fatigue. The follow-up examinations shall take place at each follow up visit , measuring those parameters recorded at the baseline examination. The further follow-up examinations shall correspond to those carried out as standard after-care investigations.

The secondary endpoints such as fatigue and quality of life shall be recorded using validated questionnaires (EORTC QLQ FA13 and EORTC QLQ BM22. All patients will also be asked to record their pain history using a pain diary (documentation of medication daily during treatment, once weekly after the end of treatment, VAS pain scale). Furthermore, the local control was assessed by means of CT images taken prior to, three and six months after RT. The pain response was documented on the VAS (range 0-10). Complete response (CR) was defined as VAS = 0 after three and six months, partial response (PR) as an improvement by at least two score points after three and six months. Overall survival (OS) was defined as time from initial diagnosis until death, bone survival as time from initial diagnosis of spinal bone metastasis until death.

In each case, the treatment plan was designed based on tumor geometry, proximity to the spinal cord, and location. The planning tumor volume (PTV) was defined as equal to gross tumor volume (GTV). The spinal cord, cauda equina, nerve roots, and bowel were contoured as organs at risk (OARs) and critical structures. An inverse treatment planning method along with a linear optimization algorithm were employed. The target volume was designated to include either the GTV and the entire vertebral body (WB group) or only the GTV (PB group) at each spinal level.