Get access

Analysis of the impact of chest wall constraints on eligibility for a randomized trial of stereotactic body radiotherapy of peripheral stage I non-small cell lung cancer

Authors

  • Shankar Siva,

    Corresponding author
    1. Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
    • Department of Radiation Oncology, University of Melbourne, Melbourne, Victoria, Australia
    Search for more papers by this author
    • Equal first authors.
  • Mark Shaw,

    1. Department of Radiation Oncology, University of Melbourne, Melbourne, Victoria, Australia
    2. Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
    Search for more papers by this author
    • Equal first authors.
  • Brent Chesson,

    1. Radiation Therapy, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
    Search for more papers by this author
  • Suki Gill,

    1. Department of Radiation Oncology, University of Melbourne, Melbourne, Victoria, Australia
    Search for more papers by this author
  • David Ball

    1. Department of Radiation Oncology, University of Melbourne, Melbourne, Victoria, Australia
    Search for more papers by this author

  • S Siva MBBS, FRANZCR; M Shaw MBBS, FRANZCR; B Chesson BAppSC(Hons); S Gill MBBS, MRCP, FRCR, FRANZCR; D Ball MD, MBBS, FRANZCR.
  • Conflict of interest: None.

Correspondence

Dr Shankar Siva, Department of Radiation Oncology, Level 3 Peter MacCallum Cancer Centre, St Andrews Place, East Melbourne, Vic. 3002, Australia.

Email: shankar.siva@petermac.org

Abstract

Introduction

Chest wall toxicities are recognized complications of stereotactic radiotherapy (SBRT) in non-small cell lung cancer. To minimize toxicity, the Trans-Tasman Radiation Oncology Group (TROG) 09.02 ‘CHISEL’ study protocol excluded patients with tumours within 1 cm of the chest wall. The purpose of this study is to evaluate the implication of chest wall proximity constraints on patient eligibility, toxicity and potential accrual.

Methods

Exclusion zones of 1 cm beyond the mediastinum and 2 cm beyond the bifurcation of the lobar bronchi were incorporated into the CHISEL credentialing CT dataset. Volumes of lung within which tumours varying from 1 cm to 5 cm in diameter may occupy and remain eligible for the CHISEL study were calculated. These volumes were compared to a hypothetical model in which the 1 cm chest wall proximity restriction was removed.

Results

The percentage of lung area in which a tumour mass can occupy and be suitable for CHISEL in the left and right lung were 54% and 60% respectively. Removing the constraint increased the percentage of available lung to 83% and 87% respectively. Considering a 2 cm spherical tumour, only 21% and 31% of tumours in the left and right lung would be eligible with the chest wall constraint, whilst 39% and 50% respectively would be eligible without the constraint.

Conclusions

The exclusion of tumours less than 1 cm to chest wall significantly reduces the proportion of patients eligible for the CHISEL protocol. A review of the literature pertaining to chest wall toxicity after stereotactic radiotherapy supports a change in chest wall exclusion criteria for the CHISEL study.

Ancillary