Upfront observation versus radiation for adult pilocytic astrocytoma

Authors

  • Adrian Ishkanian MSc, MD,

    1. Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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  • Normand J. Laperriere MD,

    1. Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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  • Wei Xu PhD,

    1. Department of Biostatistics, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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  • Barbara-Ann Millar MD,

    1. Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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  • David Payne MD,

    1. Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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  • Warren Mason MD,

    1. Department of Medicine, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
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  • Arjun Sahgal MD

    Corresponding author
    1. Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario, Canada
    2. Department of Radiation Oncology, Princess Margaret Hospital and the Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario, Canada
    • Princess Margaret Hospital, 610 University Avenue, Toronto, ON, M5G 2M9, Canada
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    • Fax: (416) 946-2111


Abstract

BACKGROUND:

Although pilocytic astrocytoma accounts for up to 40% of all childhood brain tumors, it is a rare disease in adults. Consequently, there are few mature data on the impact of up-front treatment options after surgery that include observation or adjuvant radiotherapy.

METHODS:

Ten women and 20 men were identified who were diagnosed with pilocytic astrocytoma from 1971 to 2007 and were retrospectively reviewed. The median patient age was 30 years (range, 18-64 years), and the median follow-up was 87 months (range, 16-420 months). Initial surgery included biopsy (10% of patients), subtotal resection (57% of patients), or gross-total resection (33% of patients). Nineteen patients were observed postoperatively, whereas 11 patients received up-front postoperative adjuvant radiotherapy (50 grays in 25 fractions). No patient received adjuvant or concurrent chemotherapy. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Differences between survival curves were analyzed with the log-rank test.

RESULTS:

For the entire cohort, the 5-year and 10-year OS rates were 95% and 85%, respectively, and the 5-year and 10-year PFS rates were 63% and 35%, respectively. The median PFS was 8.4 years. Initial radiation, compared with observation, did not have an impact on OS but significantly improved PFS. The 5-year PFS rate for patients who were observed versus those who received radiation was 42% versus 91%, respectively; and, at 10 years, the PFS rate was 17% versus 60%, respectively (P = .005). Patients who progressed after observation (11 of 19 patients) received various salvage therapies, resulting in a 2-year PFS rate of 68% compared with 33% for patients who progressed after initial radiation (3 of 11 patients) and were salvaged with either chemotherapy or surgery (P = .1).

CONCLUSIONS:

Adjuvant radiotherapy for pilocytic astrocytoma significantly prolonged PFS at both 5 years and 10 years compared with observation. However, equivalent OS was observed, which reflected the efficacy of salvage therapies. Cancer 2011;. © 2011 American Cancer Society.

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