Prospective Study of Hippocampal-Sparing Prophylactic Cranial Irradiation in Limited-Stage Small Cell Lung Cancer

Journal Article · Sat Jul 01 04:00:00 EDT 2017 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/J.IJROBP.2017.03.009· OSTI ID:22722980

Hales, Russell K.; Anderson-Keightly, Heather ^[1]; Zhou, Xian C. ^[2]; Kummerlowe, Megan ^[1]; Sair, Haris I. ^[3]; Duhon, Mario; Kleinberg, Lawrence ^[1]; Rosner, Gary L. ^[2]; Vannorsdall, Tracy ^[4]

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1. Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University, Baltimore, Maryland (United States)
2. Division of Biostatistics and Bioinformatics, Department of Oncology, The Johns Hopkins University, Baltimore, Maryland (United States)
3. Department of Radiology, The Johns Hopkins University, Baltimore, Maryland (United States)
4. Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University, Baltimore, Maryland (United States)

Purpose: To prospectively evaluate cognitive function and intracranial failure patterns after hippocampal-sparing prophylactic cranial irradiation (PCI) for limited-stage small cell lung cancer (SCLC). Methods and Materials: Adults with limited-stage SCLC, achieving a complete response to chemoradiotherapy and no brain metastases, were eligible. Patients received PCI 25 Gy/10 fractions, with a mean hippocampal dose limited to <8 Gy and ≥90% of the brain receiving 90% of the prescription. A diverse battery of neuropsychological testing was performed at baseline and 6 and 12 months after PCI. Brain MRI scans were performed at baseline and 6, 12, 18, and 24 months. The primary endpoint was memory measured by the Hopkins Verbal Learning Test-Revised Delayed Recall at 6 months after PCI. The 25-Gy arm of Radiation Therapy Oncology Group protocol 0212 was used as a reference of potential efficacy. Development of intracranial metastases was recorded. Overall survival and progression-free survival were estimated using the Kaplan-Meier method. Results: Eight men and 12 women with a median age of 61 years enrolled. Two-year overall survival was 88% (95% confidence interval 68%-100%). There was no significant decline in performance between baseline and 6 or 12 months for any of the tests. The association between baseline intelligence quotient and change in performance on testing was not significant. Magnetic resonance imaging revealed asymptomatic brain metastases at a cumulative rate of 20%, with no concurrent extracranial progression. Two patients developed a metastasis in the under-dosed region. Neither involved the dentate gyrus, but 1 involved the avoidance region. Both patients concurrently developed additional metastasis in fully treated brain regions. There were 2 neurologic deaths. Conclusions: This prospective study suggests a potential benefit of hippocampal sparing in limiting the neuropsychological sequelae of brain radiation, but with a risk of failures in the spared region. These data strongly support continued enrollment on ongoing cooperative group randomized trials. Clinical Trials registration number: (NCT01797159).

• OSTI ID: 22722980
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 3 Vol. 98; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BRAIN
CLINICAL TRIALS
COMBINED THERAPY
GY RANGE
IRRADIATION
LUNGS
NEOPLASMS
NMR IMAGING
PATIENTS
RADIATION DOSES
RADIATION HAZARDS