In 2004, our institution began using four-dimensional computed tomography (4DCT) simulation
and then intensity-modulated radiotherapy (IMRT) (4DCT/IMRT) instead of three-dimensional
conformal radiotherapy (3DCRT) for the standard treatment of non-small-cell lung cancer
(NSCLC). This retrospective study compares disease outcomes and toxicity in patients
treated with concomitant chemotherapy and either 4DCT/IMRT or 3DCRT.
A total of 496 NSCLC patients have been treated at M. D. Anderson Cancer Center between
1999 and 2006 with concomitant chemoradiotherapy. Among these, 318 were treated with
CT/3DCRT and 91 with 4DCT/IMRT. Both groups received a median dose of 63 Gy. Disease
end points were locoregional progression (LRP), distant metastasis (DM), and overall
survival (OS). Disease covariates were gross tumor volume (GTV), nodal status, and
histology. The toxicity end point was Grade >or=3 radiation pneumonitis; toxicity
covariates were GTV, smoking status, and dosimetric factors. Data were analyzed using
Cox proportional hazards models.
Mean follow-up times in the 4DCT/IMRT and CT/3DCRT groups were 1.3 (range, 0.1-3.2)
and 2.1 (range, 0.1-7.9) years, respectively. The hazard ratios for 4DCT/IMRT were
<1 for all disease end points; the difference was significant only for OS. The toxicity
rate was significantly lower in the IMRT/4DCT group than in the CT/3DCRT group. V20
was significantly higher in the 3DCRT group and was a significant factor in determining
toxicity. Freedom from DM was nearly identical in both groups.
Treatment with 4DCT/IMRT was at least as good as that with 3DCRT in terms of the rates
of freedom from LRP and DM. There was a significant reduction in toxicity and a significant
improvement in OS.
Published by Elsevier Inc.