Long-term follow up of very low-dose LINAC based stereotactic radiotherapy in temporal lobe epilepsy

Summary Objective Several prospective multicenter studies have demonstrated high safety efficacy for mesial temporal lobe epilepsy (TLE) with Gamma Knife radiosurgery using 24 Gy at the margin. In this paper we reported the long-term outcome of 7 patients with TLE treated with very low-dose linear accelerator (LINAC) based fractionated stereotactic radiotherapy (FSRT). We also discussed the feasibility of LINAC for TLE. Methods To record the treatment process, outcomes and side effects for 7 patients with TLE treated with low-dose LINAC, whose marginal dose of all cases was 12 Gy at the 85% isodose line, and post-FSRT seizure frequencies were compared with those of patients pre-FSRT. One special case (case 6) was reported in detail. Results Reduction of seizure frequency post-FSRT was 50% in 2 cases, 30% in 1 case, and 0% in 2 cases, and seizure frequency increased more than 100% in 2 cases. No patient was seizure free at the last follow up. 2 cases presented transitory complications and 2 cases showed an obvious drop in IQ, memory decline and permanent neurologic complications, including partial aphasia and mild hemiplegia in 1 case, progressive ataxia and cognition decline in another case. Conclusion Outcome of TLE treated by very low-dose LINAC based FSRT was poor because of mild reduction in seizure attack frequency and serious complications.