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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
Author(s) -
Siva Shankar,
Shaw Mark,
Chesson Brent,
Gill Suki,
Ball David
Publication year - 2012
Publication title -
journal of medical imaging and radiation oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.31
H-Index - 43
eISSN - 1754-9485
pISSN - 1754-9477
DOI - 10.1111/j.1754-9485.2012.02437.x
Subject(s) - medicine , radiology , lung , lung cancer , mediastinum , stage (stratigraphy) , nuclear medicine , paleontology , biology
Chest wall toxicities are recognized complications of stereotactic radiotherapy ( SBRT ) in non‐small cell lung cancer. To minimize toxicity, the T rans‐ T asman R adiation O ncology G roup ( 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.