Intensity-Modulated Radiotherapy (IMRT) versus Volumetric Modulated Arc Therapy (VMAT) for Locally Advanced Non- Small Cell Lung Cancer

Background: For stage III non-small cell lung cancer (NSCLC), current
treatment is conventional radiotherapy, concurrently with platinum
chemotherapy with or without induction chemotherapy, with consolidation
durvalumab. Volumetric modulated arc therapy (VMAT) allows higher target
conformity and homogeneity with less scatter dose due to reducing MU, causing
fewer secondary malignancies and less treatment time.
Aim: Comparison between IMRT and VMAT in stage III NSCLC patients
regarding dosimetric differences and clinical outcome including response,
survival and toxicity and their correlation with clinicopathological
characteristics.
Methods: This is a prospective randomized study using simple randomization
by coin which included 60 patients with stage III NSCLC who received
concurrent chemoradiation at Clinical Oncology and Nuclear Medicine
Department Tanta University Hospitals comparing clinical outcome and
correlation with clinicopathological characteristics and dosimetric parameters
throughout the period from July 2021 to June 2023. Thirty patients received
IMRT (Group A) and 30 received VMAT (Group B).
Results: There was no significant difference in dosimetric parameters except for
contralateral mean dose and esophageal parameters without effect on toxicity.
The main significant difference was shorter delivery time and less monitor units
in VMAT group. There was no significant difference in response. Progression
free survival was significantly higher in VMAT with significant correlation to
grade and mean esophageal dose.
Conclusion: The VMAT provides shorter delivery time and less monitor units
with less treatment cost. Both IMRT and VMAT are similar in toxicity.
Progression free survival is higher in VMAT with similar treatment response.