Adaptive radiation therapy for cervical esophageal cancer: dosimetric and volumetric analysis

Abstract

Background: Cervical esophageal cancer (CEC) patients may suffer from significant anatomical changes due to tumor shrinkage or weight loss during radiotherapy. The aim of the study is to evaluate the volumetric and dosimetric changes in the target and critical volumes of CEC patients by using adaptive radiotherapy (ART) technique. Methods: Seven CEC patients treated in helical tomotherapy (HT) unit was analyzed. All patients had a replanning CT simulation at 3rd (CT2) and 5th (CT3) weeks in addition to the initial CT (CT1). Volumetric and dosimetric changes of target and organs at risk (OAR) were evaluated. Results: The average weight loss of the patients was 9.03%. The major changes of the planning target volume (PTV), PTV boost, right and left parotid volumes were 4.74%; 15.93%; 26.82% and 26.64%, respectively. Using ART software was evaluated with first planning values (CT1) and pre-CT2-CT3 verification values. The correlation was decrease of the D95 and increase of the Dmax was statistically significant. When evaluated the varying values of the new CTs, there was no significant change between the initial PTV and adapted PTV's. But a significant decrease was observed at the summation plan for left and right parotids (P<0.05). The mean dose reductions of left and right parotid were 2.48 and 2.49 Gy, respectively. Conclusions: Our results showed that using ART technique was beneficial to ensure adequate doses to the target volumes and safe doses to the OARs for the patients who need replanning during RT in uncommon CEC patients.

Early Prediction of Planning Adaptation Requirement Indication Due to Volumetric Alterations in Head and Neck Cancer Radiotherapy: A Machine Learning Approach

“…In fact, recent evidence suggests that planning adaptations are required during RT or between RT sessions, especially for patients who present more than 20–30% volumetric changes in parotid glands or Clinical Target Volume (CTV) [ 7 , 8 ]. To alleviate such anatomical differences, offline or online Adaptive Radiotherapy Treatment (ART) has been implemented, adapting the patient’s initial volumes and planning to the current anatomy and position [ 9 , 10 ]. However, ART’s complicated computations (where clinicians have to constantly analyze new scans and create new plans), significantly increase the overall workload and resource utilization burden, underlying the need for an efficient and cost-effective approach for the identification of the patients that will benefit from ART [ 11 ].…”

Deformable image registration to assist clinical decision for radiotherapy treatment adaptation for head and neck cancer patients

“…ART incorporates daily anatomical changes to assess the necessity for treatment planning adaption during radiotherapy followed by the design of new plans [15]. Treatment planning is accomplished via offline or online ART.…”