Frontiers in Oncology (Mar 2016)

INFLUENCE OF DOSE RATE ON THE CELLULAR RESPONSE TO LOW- AND HIGH-LET RADIATIONS

  • Anne-Sophie eWozny,
  • Anne-Sophie eWozny,
  • Gersende eAlphonse,
  • Gersende eAlphonse,
  • Priscillia eBattiston-Montagne,
  • Stéphanie eSimonet,
  • Delphine ePoncet,
  • Delphine ePoncet,
  • Etienne eTesta,
  • Jean-Baptiste eGuy,
  • Jean-Baptiste eGuy,
  • Chloé eRancoule,
  • Nicolas eMagne,
  • Michael eBeuve,
  • Claire eRodriguez-Lafrasse,
  • Claire eRodriguez-Lafrasse

DOI
https://doi.org/10.3389/fonc.2016.00058
Journal volume & issue
Vol. 6

Abstract

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Nowadays, head and neck squamous cell carcinoma (HNSCC) treatment failure is mostly explained by loco-regional progression or intrinsic radioresistance. Radiotherapy has recently evolved with the emergence of heavy ion radiations or new fractionation schemes of photon therapy which modify the dose-rate of treatment delivery. The aim of the present study was then to evaluate the in vitro influence of a dose rate variation during conventional radiotherapy or carbon ion hadrontherapy treatment in order to improve the therapeutic care of patient. In this regard, two HNSCC cell lines were irradiated with photons or 72MeV/n carbon ions at a dose rate of 0.5, 2 or 10Gy/min.For both radiosensitive and radioresistant cells, the change in dose rate significantly affected cell survival in response to photon exposure, this variation of radiosensitivity was associated to the number of initial and residual DNA double-strand breaks. By contrast, the dose rate change did not affect neither cell survival nor the residual DNA double-strand breaks after carbon ion irradiation. As a result, the Relative Biological Efficiency at 10% survival increased when the dose rate decreased.In conclusion, in the radiotherapy treatment of HNSCC, it is advised to remain very careful when modifying the classical schemes towards altered-fractionation. At the opposite, as the dose rate does not seem to have any effects after carbon ion exposure, there is less need to adapt hadrontherapy treatment planning during active system irradiation

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