Using units of CEM 43°C T90, local hyperthermia thermal dose can be delivered as prescribed

D. E. Thrall, G. L. Rosner, C. Azuma, S. M. Larue, B. C. Case, T. Samulski, M. W. Dewhirst

Research output: Contribution to journalArticle

Abstract

A randomized study was designed in dogs with spontaneous soft tissue sarcomas to gain information about the relationship between hyperthermia dose and outcome. The study compared two levels of thermal dose applied to dogs with heatable tumours, so it was necessary to deliver either a low (2-5 CEM 43°C T90) or high (20-50 CEM 43°C T90) thermal dose as precisely as possible. It was also desirable to have similar numbers of hyperthermia treatments in each thermal dose group. Identification of heatable tumours and randomization to high or low heat dose group was done during the first hyperthermia treatment. This was readily accomplished using mapping of temperatures in thermometry catheters, manual recording of thermal data, and visual inspection of raw thermal data with subsequent adjustment of the duration of the hyperthermia treatment. An analysis of precision of thermal dose delivery was conducted after approximately 50% of projected accrual had been met in a randomized phase III assessment of thermal dose effect. Fifty-four dogs were eligible for randomization; in 48 dogs the tumour was deemed heatable according to predetermined temperature criteria applied during the first heat treatment. Twenty-four dogs were randomized to the high heat dose group, and 24 to the low heat dose group. Median (range) total thermal dose for dogs in the high dose group was 43.5 CEM 43°C T90 (16.4-66.6) compared to 3.2 CEM 43°C T90 (2.1-4.6) for dogs in the low dose group. There was no overlap of thermal doses between groups. Thus, thermal dose could be delivered accurately, being within the predetermined range in 47 of the 48 dogs. Thermal dose quantified as CEM 43°C T50, however, did overlap between groups and the clinical significance of this finding will not be known until outcome data are analysed. Most dogs in both groups received five hyperthermia treatments. Median (range) treatment duration for dogs in the high dose group was 300 min (147-692) compared to 111 min (51-381) for dogs in the low dose group. Relatively simple but accurate methods of delivering prescribed thermal dose as described herein will aid the translation of clinical hyperthermia from the research setting into more general practice once the characteristics of the relationship between hyperthermia dose and outcome are understood.

Original languageEnglish (US)
Pages (from-to)415-428
Number of pages14
JournalInternational Journal of Hyperthermia
Volume16
Issue number5
DOIs
StatePublished - Jan 1 2000
Externally publishedYes

Keywords

  • Dog
  • Hyperthermia
  • Thermal dose

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)
  • Cancer Research

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