Clinical results of unconventional fractionation radiotherapy in central nervous system tumors

Marco Botturi, Laura Fariselli

Research output: Contribution to journalArticle

Abstract

Malignant brain tumors (primary and metastatic) are apparently resistant to most therapeutic efforts. Several randomized trials have provided evidence supporting the efficacy of radiation therapy. Attempts at improving the results of external beam radiotherapy include altered fractionation, radiation sensitizers and concomitant chemotherapy. In low-grade gliomas, all clinical studies with radiotherapy have employed conventional dose fractionation regimens. In high-grade gliomas, hypofractionation schedules represent effective palliative regimens in poor prognosis subsets of patients; short-term survival in these patients has not allowed to evaluate late toxicity. In tumors arising within the central nervous system, hyperfractionated irradiation exploits the differences in repair capacity between tumour and late responding normal tissues. It may allow for higher total dose and may result in increased tumor cell kill. Accelerated radiotherapy may reduce the repopulation of tumor cells between fractions. It may potentially improve tumor control for a given dose level, provided that there is no increase in late normal tissue injury. In supratentorial malignant gliomas, superiority of accelerated hyperfractionated over conventionally fractionated schedules was observed in randomized trial; however, the gain in survival was less than 6 months. At present no other randomized trial supports the preferential choice for altered fractionation irradiation. Also in pediatric brainstem tumors there are no data to confirm the routine use by hyperfractionated irradiation, and significant late sequelae have been reported in the few long-term survivors. Shorter treatment courses with accelerated hyperfractionated radiotherapy may represent a useful alternative to conventional irradiation for the palliation of brain metastases. Different considerations have been proposed to explain this gap between theory and clinical data. Patients included in dose/effect studies are not stratified by prognostic factors and other treatment-related parameters. This observation precludes any definite conclusion about the relative role of conventional and of altered fractionation. New approaches are currently in progress. More prolonged radiation treatments, up to higher total doses, could delay time to tumor progression and improve survival in good prognosis subsets of patients; altered fractionation may be an effective therapeutic tool to achieve this goal.

Original languageEnglish
Pages (from-to)176-187
Number of pages12
JournalTumori
Volume84
Issue number2
Publication statusPublished - Mar 1998

Fingerprint

Central Nervous System Neoplasms
Radiotherapy
Glioma
Neoplasms
Survival
Appointments and Schedules
Brain Stem Neoplasms
Dose Fractionation
Radiation-Sensitizing Agents
Therapeutics
Brain Neoplasms
Survivors
Central Nervous System
Radiation
Pediatrics
Neoplasm Metastasis
Drug Therapy
Wounds and Injuries
Brain

Keywords

  • Altered fractionation
  • Central nervous system
  • Radiation therapy

ASJC Scopus subject areas

  • Cancer Research

Cite this

Clinical results of unconventional fractionation radiotherapy in central nervous system tumors. / Botturi, Marco; Fariselli, Laura.

In: Tumori, Vol. 84, No. 2, 03.1998, p. 176-187.

Research output: Contribution to journalArticle

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