Escalated Maximum Dose in the Planning Target Volume Improves Local Control in Stereotactic Body Radiation Therapy for T1-2 Lung Cancer.

Takaya Inagaki,Naoko Ishida,Kiyoshi Nakamatsu,Masahiro Inada,Aritoshi Ri,Saori Tatsuno,Yutaro Wada,Hiroshi Doi,Takuya Uehara,Yasumasa Nishimura,Makoto Hosono

doi:10.3390/cancers14040933

Abstract

Simple SummaryStereotactic body radiotherapy (SBRT) is a treatment option for early-stage lung cancer. The purpose of this study was to investigate the optimal dose distribution and prognostic factors for local control (LC) in 100 patients with lung cancer who underwent SBRT. The 1- and 3-year LC rates were 95.7% and 87.7%, respectively. In summary, we found that squamous cell carcinoma (SQ), T2 tumor stage, and a lower radiotherapy dose were associated with poorer LC in lung cancer. The lower rate of LC in patients with SQ vs. non-SQ was limited to cases with a Dmax below 125 Gy (BED10).Stereotactic body radiotherapy (SBRT) is a treatment option for early-stage lung cancer. The purpose of this study was to investigate the optimal dose distribution and prognostic factors for local control (LC) after SBRT for lung cancer. A total of 104 lung tumors from 100 patients who underwent SBRT using various treatment regimens were analyzed. Dose distributions were corrected to the biologically effective dose (BED). Clinical and dosimetric factors were tested for association with LC after SBRT. The median follow-up time was 23.8 months (range, 3.4–109.8 months) after SBRT. The 1- and 3-year LC rates were 95.7% and 87.7%, respectively. In univariate and multivariate analyses, pathologically confirmed squamous cell carcinoma (SQ), T2 tumor stage, and a Dmax < 125 Gy (BED10) were associated with worse LC. The LC rate was significantly lower in SQ than in non-SQ among tumors that received a Dmax < 125 Gy (BED10) (p = 0.016). However, there were no significant differences in LC rate between SQ and non-SQ among tumors receiving a Dmax ≥ 125 Gy (BED10) (p = 0.198). To conclude, SQ, T2 stage, and a Dmax < 125 Gy (BED10) were associated with poorer LC. LC may be improved by a higher Dmax of the planning target volume.

Highlights

Stereotactic body radiation therapy (SBRT), known as stereotactic ablative radiation therapy, has been recommended as a therapeutic modality for medically inoperable early-stage non-small-cell lung cancer [1]
To compare the various prescribed methods, we reviewed the dose-volume histogram (DVH) parameters of all clinical plans
Eight local failure (LF) were diagnosed by 18FDG uptake on 18FDG-positron emission tomography (PET)/computed tomography (CT) and continuous growth on CT images, and two LFs were diagnosed by continuous growth on CT images

Summary

Introduction

Stereotactic body radiation therapy (SBRT), known as stereotactic ablative radiation therapy, has been recommended as a therapeutic modality for medically inoperable early-stage non-small-cell lung cancer [1]. The use of high-precision techniques is critical for the administration of SBRT, and large dose gradients can be located on the target to achieve maximum therapeutic efficacy while minimizing toxicity to normal tissue [4]. Respiratory management techniques, and dose calculation algorithms have been improved to maximize precision and minimize errors. Both non-coplanar three-dimensional conformal multiple-beam irradiation techniques and intensity-modulated radiotherapy have recently been used to improve the homogeneity of radiation doses and reduce doses to organs at risk [4]. SBRT is widely accepted as a treatment option for early-stage lung tumors and achieves 80–97% local control (LC) rates by using a BED10 of >100 Gy [6,7,8,9,10,11,12]

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