Accelerated fractionation vs hyperfractionation: rationales for several treatments per day

Journal Article · Tue Feb 01 04:00:00 EST 1983 · Int. J. Radiat. Oncol., Biol. Phys.; (United States)

DOI:https://doi.org/10.1016/0360-3016(83)90089-5· OSTI ID:5515810

Thames, Jr, H D ^[1]; Peters, L J; Withers, H R; Fletcher, G H

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1. Univ. of Texas System Cancer Center, Houston

Treatment with several doses per day offers the prospect of a significant therapeutic gain using readily available low LET beams. These regimens can be classified as either accelerated fractionation or hyperfractionation according to their rationales. With accelerated fractionation a conventional number of dose fractions is delivered in a significantly shortened overall treatment time in order to reduce the opportunity for tumor cell regeneration during treatment. With hyperfractionation, on the other hand, a large number of significantly reduced dose fractions is used to give a greater total dose in a conventional overall treatment time. The rationale for this strategy is threefold: 1)increased opportunity for tumor cell redistribution and reoxygenation between dose fractions: 2)a possibly lower oxygen enhancement ratio with small incremental doses; and 3)differential sparing of late reacting normal tissues with small dose fractions. A review of the published clinical experience with multiple fractions per day treatment reveals few studies of either pure accelerated fractionation or hyperfractionation since both are limited by acute normal tissue reactions. This has led to a variety of hybrid regimens, some of which have no clear rationale. The choice between accelerated fractionation and hyperfractionation is determined by the regenerative capability of tumor clonogens during treatment. A method of selection based on potential doubling times is presented.

• OSTI ID: 5515810
• Journal Information: Int. J. Radiat. Oncol., Biol. Phys.; (United States), Journal Name: Int. J. Radiat. Oncol., Biol. Phys.; (United States) Vol. 9:2; ISSN IOBPD
• Country of Publication: United States
• Language: English

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62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
DELAYED RADIATION EFFECTS
FRACTIONATED IRRADIATION
IRRADIATION
MEDICINE
NUCLEAR MEDICINE
PATIENTS
PLANNING
RADIATION EFFECTS
RADIOLOGY
RADIOTHERAPY
SIDE EFFECTS
THERAPY