Salvage craniospinal irradiation with an intensity modulated radiotherapy technique for patients with disseminated neuraxis disease

Abstract

PurposeTo report the use and results of a novel intensity modulated radiotherapy (IMRT)-based technique used for salvage craniospinal irradiation (CSI) in 6 patients who developed neuraxis disease after initial high-dose conformal radiotherapy (RT) to the brain. Methods and MaterialsAfter Institutional Review Board approval, all patients treated for disseminated leptomeningeal disease with salvage CSI using IMRT with conventional external beam radiotherapy were identified. The medical records and radiotherapy dosimetry were reviewed. Tolerance, morbidity, tumor control, and overall survival were evaluated. ResultsSix patients who received IMRT-based salvage CSI were identified. The median age was 6.5 years (range 2- 34 years) at initial RT and 7.7 years (range, 3-35 years) at salvage CSI. Disease progression necessitating salvage CSI was noted at a median of 10 months (range, 1-26 months) from the initial RT. The original disease site remained well controlled in all 6 patients. The median dose of the initial RT treatment was 52 Gy (range, 30.6-60 Gy). Salvage CSI dose was 36 Gy in 20 fractions in all 6 patients. IMRT was used to treat the cranial contents excluding the previously treated area. Five pediatric patients received electron beams to spine and 1 adult patient received photon beams to spine. IMRT allowed a conformal and uniform dose distribution to the target tissue while excluding previously treated areas. Salvage CSI dose of 36 Gy, delivered using IMRT and 36 Gy using electrons or photons to the spine, proved effective in providing good control of the disease. ConclusionsThis technique of salvage CSI was effective in this patient cohort for leptomeningeal dissemination occurring outside of an area of focal irradiation. The technique was well tolerated and thus far has not been associated with any significant toxicity. Salvage therapy has been effective in 4 of the 6 patients thus far.