Work

Rthp-08. Hippocampal Avoidance Whole Brain Radiation Therapy (ha-wbrt) Plus Simultaneous Integrated Boost (sib) to Gross Disease: an Alternative to Whole Brain Radiation (wbrt) With Stereotactic Radiosurgery (srs)?

Year: 2017

Type: article

Abstract: WBRT with SRS offers improved intracranial disease control relative to SRS alone but poorer neurocognitive outcomes. HA-WBRT + SIB is an attractive alternative to WBRT with SRS due to omission of a separate stereotactic procedure, reduced treatment time, and potentially safer treatment of large tumors that are poor candidates for SRS. We performed a single-institution, retrospective review of patients treated with HA-WBRT + SIB. Toxicity was graded according to CTCAE v4.0. We identified 24 patients treated with HA-WBRT + SIB between 2014 and 2017 with a median of three SIBs (range: 1 – 12 SIBs) occupying a median volume of 8.9 cm3 (range: 0.6 – 127.0 cm3). Median hippocampal volume was 4.8 cm3 (range: 3.1 – 6.9 cm3). The most common fractionation was HA-WBRT 30 Gy in 15 fractions with SIB to 37.5 Gy using intensity-modulated radiation therapy (n=14) or volumetric-modulated arc therapy (n=10) planning. Median D99% to bilateral hippocampi was 8.0 Gy +/- 0.9 Gy. Median age was 65.7 years. Median follow-up was 6.3 months (range: 0.8 – 34.1 months). The most common diagnosis was non-small cell lung cancer (n=17). The one-year intracranial disease control rate was 70.8%. One patient had hippocampal failure, and two patients had peri-hippocampal failure within five mm of the hippocampal border. VMAT reduced average treatment time per fraction by 48% relative to IMRT (11.0 min vs 21.1 min, p < 0.001). No toxicity greater than grade two was observed. HA-WBRT + SIB is well-tolerated and achieves high intracranial disease control for brain metastases. A prospective comparison of HA-WBRT + SIB versus WBRT with SRS with endpoints of neurocognitive function and intracranial disease control is warranted.

Source: Neuro-Oncology

DOI: 10.1093/neuonc/nox168.893