Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Original Article
  • Published:

Effect of Dose Fractionation on the Enhancement by Radiation or Cyclophosphamide of Artificial Pulmonary Metastases

Abstract

Thoracic irradiation or cyclophosphamide (CP) treatment of mice before an i.v. injection of tumour cells enhances the number of lung colonies produced by a factor of up to 100+. The effect of fractionation of the X-ray or CP dose on this phenomenon was investigated in several ways.

The dose-response curve for the number of lung colonies as a function of the dose of thoracic irradiation was linear, and the degree of enhancement was independent of the number of tumour cells injected. Splitting a dose of 1,000 rad into 2 equal fractions separated by times varying from 1 to 24 h gave the same enhancement as that produced by a single dose of 1000 rad. Similarly, fractionation of 1000 rad into 5 × 200 rad, or 2000 rad into 5 × 400 rad (each interval between fractions being 3 h) had no effect on the radiation enhancement of colony formation.

A single dose of 200 mg/kg of CP was compared with 3 doses of 66·7 mg/kg (each dose separated by 12 h) and with a continuous infusion of 200 mg/kg given over 24 h. In this case, fractionation and infusion produced a small reduction in the CP-induced increase, but the factor of colony enhancement compared to control mice remained >100.

These data emphasize the potential hazard of prophylactic treatment of pulmonary metastases by X-rays or CP in clinical situations in which control of the primary tumour is not achieved.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Brown, J., Marsa, G. Effect of Dose Fractionation on the Enhancement by Radiation or Cyclophosphamide of Artificial Pulmonary Metastases. Br J Cancer 37, 1020–1025 (1978). https://doi.org/10.1038/bjc.1978.148

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1038/bjc.1978.148

This article is cited by

Search

Quick links