Reirradiation for recurrent primary central nervous system tumors: Eight-year audit from a tertiary cancer care center in South India.

BACKGROUND: Radiation therapy is a major treatment option in the management of primary central nervous system (CNS) tumors, though recurrences after primary treatment, especially in high-grade glial tumors, is a challenge for treating physician. Advances in the field of radiation have made reirradiation a feasible option in recurrent CNS tumors.
MATERIALS AND METHODS: Details of patients with primary CNS lesions who presented between 2009 and 2016, with recurrent CNS lesions, and who were treated with reirradiation were retrieved from electronic medical records, as a departmental audit, and the outcome was analyzed.
RESULTS: A total of 33 patients received reirradiation. Median follow-up was 112.7 months. Median age at presentation was 36 years. On completing initial treatment, 42.4% had no residual disease. Median time to symptomatic recurrence was 51.33 months. For reirradiation, stereotactic radiotherapy was used in 27.3%, stereotactic radiosurgery in 12.1%, and intensity-modulated radiation therapy in 36.4%. Mean cumulative 2 Gy equivalent dose (EQD2) was 111.00 ± 15.287 Gy. At the last follow-up, 57.6% of patients were alive, and 27.3% had succumbed to the disease. Median OS was 187.67 months. Three-year survival after reirradiation was 74.1%.
CONCLUSION: Our study is probably one of the first from the Indian subcontinent analyzing a series of reirradiation in primary CNS tumors. Our survival subsequent to reirradiation is comparable to that in available literature; which are also mostly retrospective. Our analysis also substantiates that younger patients, longer intervals between the two sets of radiation and biologically effective dose <100 Gy and EQD2Cumulativeof <100 Gy are factors that favorably improve the survival after reirradiation as has been shown in literature.