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Early-stage central lung cancer and volumetric modulated arc therapy: a dosimetric case study with literature review.

BACKGROUND/AIM
In the present article we review on the use of Volumetric Modulated Arc Therapy (VMAT) for a small lung nodule that was centrally located in close proximity to the mediastinal structures.


CASE REPORT
An inoperable patient with central, clinical stage IA adenocarcinoma of the right lung was treated with external-beam radiation therapy of 52.5 Gy in 15 factions. A single 360° coplanar arc VMAT plan (360-VMAT) was used for treatment and compared to step-and-shoot Intensity Modulation Radiotherapy (IMRT) and a single 180° ipsilateral partial arc VMAT plan (180-VMAT).


RESULTS
Planning Target Volume (PTV) coverage was not different, and 360-VMAT had the highest dose homogeneity. Both 360-VMAT and 180-VMAT reduced esophageal dose compared to IMRT. While IMRT had the lowest lung dose, all 3 plans achieved acceptable sparing of the lung. 180-VMAT had the highest dose conformity. Both 360-VMAT and 180-VMAT improved esophageal sparing compared to IMRT.


CONCLUSION
Use of VMAT in early-stage, centrally located NSCLC is a promising treatment approach and merits additional investigation.