The interaction of cisplatin plus etoposide with radiation ± hyperthermia

M. Raphael Pfeffer, Beverly A. Teicher, Sylvia A. Holden, Antoine Al-Achi, Terence S. Herman

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The addition of concurrent etoposide and cisplatin to radiation ± hyperthermia was evaluated in the murine FSaIIC fibrosarcoma tumor system. Tumor growth delay (TGD) demonstrated that when the drugs were tested with radiation (3 Gy daily × 5) plus (43° × 30 min) local hyperthermia, cisplatin/hyperthermia/radiation (TGD ∼ 25 days) was significantly more effective than etoposide/hyperthermia/radiation (TGD ∼ 14 days). The addition of etoposide to cisplatin/hyperthermia/radiation, however, yielded a significantly longer growth delay (∼34 days). Tumor cell survival studies demonstrated that hyperthermia (43°C, 30 minutes) was dose modifying for etoposide cytotoxicity (dose modifying factor ∼ 2.0 as determined by comparisons of the slopes of the curves). The addition of etoposide to cisplatin modified cisplatin killing only slightly at 37°C or 43°C. Considerable additional cell kill was observed over a range of radiation doses with cisplatin, hyperthermia, and etoposide added singly or in combination, especially at the lowest radiation dose tested (5 Gy), but essentially no dose modification was observed. Evaluation of Hoechst 33342 dye-selected tumor subpopulations demonstrated that cisplatin, etoposide, radiation (10 Gy), etoposide plus radiation, and cisplatin plus radiation killed significantly fewer dim (presumably hypoxic) cells than bright (presumably normally oxygenated) cells. Hyperthermia killed more dim than bright cells. The combination of hyperthermia with cisplatin and radiation, however, resulted in ∼5-fold lesser kill in dim cells, and the addition of etoposide increased this differential to 6.4-fold. These results indicate that etoposide adds small but measurable antitumor effects when used with cisplatin alone or with cisplatin in combination with radiation hyperthermia (especially at lower radiation fraction sizes).

Original languageEnglish (US)
Pages (from-to)1439-1447
Number of pages9
JournalInternational journal of radiation oncology, biology, physics
Volume19
Issue number6
DOIs
StatePublished - Dec 1990
Externally publishedYes

Keywords

  • CDDP
  • Etoposide
  • Hyperthermia
  • Trimodality therapy

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research

Fingerprint

Dive into the research topics of 'The interaction of cisplatin plus etoposide with radiation ± hyperthermia'. Together they form a unique fingerprint.

Cite this