Study objective: A prospective study was undertaken to
assess the efficacy and toxicity of conformal proton-beam radiotherapy
for early-stage, medically inoperable non-small cell lung cancer.
Design: Eligible patients had clinical stage I to IIIa
non-small cell lung cancer and were not candidates for surgical
resection for medical reasons or because of patient refusal. Patients
with adequate cardiopulmonary function received 45 Gy to the
mediastinum and gross tumor volume with photons with a concurrent
proton boost to the gross tumor volume of an additional 28.8 cobalt
gray equivalents (CGE). Total tumor dose was 73.8 CGE given over 5
weeks. Patients with poor cardiopulmonary function received proton-beam
radiotherapy to the gross tumor volume only, with 51 CGE given in 10
fractions over a 2-week period.
patients were treated in the study from July 1994 to March 1998.
Clinical staging of patients was as follows: stage I, 27 patients;
stage II, 2 patients; and stage IIIa, 8 patients. Eighteen patients
received a combination of protons and x rays, while 19 patients
received proton-beam radiation only. Follow-up of evaluable patients
ranged from 3 to 45 months, with a median of 14 months. Two patients in
the proton and photon arm developed pneumonitis that resolved with oral
steroids; otherwise, no significant toxicities were encountered. The
actuarial disease-free survival at 2 years for the entire group was
63%; for stage I patients, disease-free survival at 2 years was 86%.
Local disease control was 87%.
Preliminary results from this study indicate that proton-beam
radiotherapy can be used safely in this group of patients. Disease-free
survival and local control appear to be good and compare favorably with
published reports utilizing conventional photon