This document summarizes a study on using helical tomotherapy to treat intracranial skull base meningiomas. 27 patients with 28 meningiomas were treated with tomotherapy between 2009-2015. Histologically, 64% were typical meningiomas and 36% were atypical. Acute toxicity was mild in 43% of patients, with no severe toxicity. Overall local control was 86% and 96% when excluding radiation-induced meningiomas. Five-year progression-free survival was 100% for typical meningiomas and 83.3% for atypical meningiomas. The study concludes that tomotherapy is an effective treatment with excellent local control and no late toxicity.

1. INTRACRANEAL SKULL BASE MENINGIOMAS TREATED WITH TOMOTHERAPHY;
SAN SEBASTIAN ONCOLOGY-INSTITUTE
A. Goñi*; J.C. Mazabuel*; D. Ortiz de Urbina*; M. Pagola*;
B. De Paula*; E. Saenz de Urturi*; P. Fernandez*; J. Rosa*;
* Servicio de Oncología Radioterápica, Instituto Oncológico de San Sebastián – Onkologikoa .
Aims: The results of local control, toxicity and survival in patients (pts) with typical and
atypical intracranial skull base meningioma treated with helical tomotherapy (HT)
technique were retrospectively analyzed.
Methods: Between October 2009 and January 2015, a total of 27 pts and 28
meningiomas have been treated with HT (71% female and 29% male), with median age
of 61 (range, 32-83). Histologically, 64% were typical and 36% atypical meningiomas.
Three pts had meningiomatosis and 3 radiation-induced meningiomas. Seventeen out
of 28 meningiomas were previously treated (13 surgery, 4 surgery plus radiosurgery).
IMRT by using a 6MV photon fan-beam technique and tomoimage-guided was carried
out daily. The median prescribed dose was 50 Gy (typical) and 54 Gy (atypical), at 180
cGy/fraction, 5 fractions/week.
Results: The median follow-up was 29,7 months (range, 1.3 – 64 months). G1-G2
acute toxicity was reported in 43% pts; no ≥ G3 toxicity was seen. G1-G2 chronic
toxicity was 4% and any late sequela of cranial nerves deficits were observed. Overall
local control was 86% and 96% if excluding radiation-induced meningiomas. Four out
of 28 meningiomas failed at 6, 14, 28 and 32 months after treatment, being 3
radiation-induced meningiomas. Fifty four percent of the 90% of pts with neurological
symptoms at diagnosis improved after treatment. Five year progression-free survival
(PFS) for typical and atypical meningiomas was 100% an 83,3% respectively. Overall
survival was 97% but cause-specific survival was 100%.
Conclusions: HT technique shows excellent local control without any late toxicity in
treatment of skull base intracranial meningiomas.