The Dosimetric Comparisons of CRT, IMRT, ARC, CRT+IMRT, and CRT+ARC of Postoperative Radiotherapy in IIIA-N2 Stage Non-Small-Cell Lung Cancer Patients

Abstract

Currently, studies about PORT in stage IIIA-N2 NSCLC patients in recent years have mostly adopted the conformal radiation therapy (CRT) technique, while other modern techniques such as intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT, hereinafter referred to as ARC), helical tomotherapy (HT), and so forth are also developing quickly. In this paper, we intended to compare the dosimetric characteristics of CRT, IMRT, ARC, CRT+IMRT, and CRT+ARC of PORT in stage IIIA-N2 NSCLC patients. Ten patients with stage IIIA-N2 completely resected NSCLC, whom were treated by PORT in the radiotherapy department of our hospital from January 1, 2017, to January 1, 2018, were randomly selected in this study. For each patient, the CRT plan, IMRT plan, ARC plan, CRT+IMRT plan, and CRT+ARC plan were designed separately on the same set of CT images. The isodose distribution and dose-volume histogram (DVH) of the five plans were compared to determine the dosimetric parameters of the targets, OAR (organs at risk), and the normal tissue (defined as body subtracted to PTV (planning target volume), B-P). No plan had absolute dosimetry advantages than any other plans. In clinical practice, the plans could be chosen according to their dosimetry characteristics.

Dosimetric comparison of four radiotherapy techniques for stage III non‑small cell lung cancer

“…Based on the above studies, the parameters of lung V 5 , V 13 , V 20 , V 30 and MLD were selected as the criteria for evaluating the lung dose in the present study. Zhang et al (8) found that the lung V 5 and V 10 values obtained using VMAT were significantly higher compared with those found when using IMRT as the technique. In the present study, lung V 5 was found to be the highest with VMAT, especially for patients with a central tumor type and larger PTV (53.59±10.51 and 55.43±10.8, respectively); however, in peripherally located cancer, this parameter was small (46.06±9.88).…”

“…3D conformal radiation therapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) now represent the two most accurate radiotherapy techniques (5,6). Numerous studies have been published that have evaluated the advantages of using IMRT over 3D-CRT, in particular with respect to: i) Improving the homogeneity index (HI) and conformity index (CI) of the PTV; and ii) decreasing the absorbed dose in OARs (7)(8)(9)(10). However, the disadvantages of using IMRT should be borne in mind; its increased treatment time may contribute to uncertainties in the prescribed treatment position, which may result in dose changes in PTV.…”

Role of Adjuvant Radiotherapy in Non-Small Cell Lung Cancer—A Review

“…A comparison of the dosimetric PORT plans of ten pN2 NSCLC patients using 3D-CRT, IMRT and VMAT was unable to reveal that any technique had absolute dosimetry advantages for all patients [ 75 ]. The selection of the technique should be individualized, balancing target coverage and protection of the organs at risk.…”

Preoperative and postoperative radiotherapy (RT) for non-small cell lung cancer: still an open question

“…However, it is unclear whether more sophisticated modern techniques, such as IMRT, can further improve the toxicity profile. A comparison of dosimetric plans using 3DCRT, IMRT, and volumetric modulated arc therapy RT in 10 patients administered PORT for pN2 disease failed to single out a technique with absolute dosimetry advantages for all patients (54). Therefore, the selection of technique should be based on each individual case using the best compromise between target coverage (efficacy) and the protection of the organs at risk.…”