Hippocampal distancing.

Since hippocampal avoidance during whole brain RT (HA-WBRT) reduces neurotoxicity, should we use a similar approach for small cell lung cancer (SCLC) prophylactic cranial irradiation (PCI)? At ASTRO 2019, preliminary results from the randomized, phase 3 PREMER trial showed significantly less memory decline with HA-PCI. Here we have results from the phase 2 SAKK 15/12 trial of “early” HA-PCI for patients with limited stage SCLC. Early because they delivered HA-PCI (25 Gy in 10 fractions) concurrent to thoracic radiation in the second cycle of chemo. In comparison to the HA-WBRT approach, they used a smaller 2 mm hippocampal avoidance region and a stricter hippocampal Dmax of 10 Gy or less. They used a fairly standard battery of cognitive tests and measures of neurocognitive failure (NCF). At 6 months, the proportion of patients with no NCF was 34%, which was fairly similar to a reference cohort from RTOG 0212 (30%). TBL: In this phase 2 trial, HA-PCI during definitive thoracic chemoradiation for LS-SCLC did not seem to significantly reduce the rate of neurocognitive failure compared to historical controls of standard sequential PCI. | Vees, Int J Radiat Oncol Biol Phys 2020