A Phase II Study of Stereotactic Body Radiotherapy and Stereotactic Body Proton Therapy for High-Risk Medically Inoperable Early-Stage Non-Small Cell Lung Cancer

Publication date: Available online 2 March 2018
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Chonnipa Nantavithya, Daniel R. Gomez, Xiong Wei, Ritsuko Komaki, Zhongxing Liao, Steven H. Lin, Melenda Jeter, Quynh-Nhu Nguyen, Heng Li, Xiaodong Zhang, Falk Poenisch, X Ronald Zhu, Peter A. Balter, Lei Feng, Noah C. Choi, Radhe Mohan, Joe Y. Chang
PurposeTo report the feasibility of conducting a randomized study to compare the toxicity and efficacy of stereotactic body radiotherapy (SBRT) versus stereotactic body proton therapy (SBPT) for high-risk medically inoperable early-stage non-small cell lung cancer (NSCLC).Methods and MaterialsWe randomly assigned patients with medically inoperable NSCLC with high-risk features (centrally located or <5 cm-T3 tumor or isolated lung parenchymal recurrences) to SBRT or SBPT. Radiation dose was 50 Gy(RBE) in four 12.5-Gy(RBE) fractions prescribed to the planning target volume. SBRT was given using 3-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT), and SBPT was given using passive scattering. Consistency in patient setup was ensured with on-board cone-beam computed tomography for the SBRT group and with orthogonal X-rays for the SBPT group.ResultsThe study closed early owing to poor accrual, largely because of insurance coverage, and lack of volumetric imaging in the SBPT group. Ultimately, 21 patients were enrolled, and 19 patients who received 50 Gy in 4 fractions were included for analysis (9 SBRT, 10 SBPT). At a median follow-up time of 32 months, median overall survival (OS) time was 28 months in the SBRT group and not reached in the SBPT group. Three-years OS was 27.8% and 90%, 3-year local control (LC) was 87.5% (8/9) and 90.0% (9/10) and 3-years regional control (RC) was 47.6% (5/9) and 90% (9/10) in SBRT and SBPT respectively. One patient in the SBPT group developed grade 3 skin fibrosis. No patients experienced grade 4/5 toxicity.ConclusionPoor accrual, due to lack of volumetric image and insurance coverage for proton therapy led to early closure of the trial and precluded accurate assessment of efficacy and toxicity. Comparable maturity of two radiotherapy modalities, particularly on-board image, and better insurance coverage for SBPT should be considered for the future studies.

Teaser

A phase II randomized study to compare SBRT vs. SBPT was terminated early due to poor accrual; treatment outcomes after SBPT appeared no worse than those after SBRT numerically with low treatment related toxicity in both groups. Lack of volumetric imaging and insurance coverage for patients treated with SBPT were the major barriers to accrual. In addition to financial issues, similar maturity of treatment planning and imaged-guided delivery are essential for future comparison studies between proton and photon therapy.


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