Quality assurance of dysphagia-optimised intensity modulated radiotherapy treatment planning for head and neck cancer.
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ABSTRACT:
SUBMITTER: Tyler J
PROVIDER: S-EPMC8560997 | biostudies-literature | 2021 Oct
REPOSITORIES: biostudies-literature
Publications
Quality assurance of dysphagia-optimised intensity modulated radiotherapy treatment planning for head and neck cancer.
Tyler Justine J Bernstein David D Seithel Matthew M Rooney Keith K Petkar Imran I Miles Elizabeth E Clark Catharine H CH Hall Emma E Nutting Chris C
Physics and imaging in radiation oncology 20211026
This study aimed to assess the impact of the margin applied to the clinical target volume, to create the planning target volume, on plan quality of a novel dysphagia-optimised intensity modulated radiotherapy technique developed within a head and neck cancer multicentre randomised controlled trial. Protocol compliant plans were used for a single benchmark planning case. Larger margins were associated with higher doses to adjacent organs at risk, particularly the inferior pharyngeal constrictor m ...[more]
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Project description:The impact of radiotherapy (RT) quality assurance (QA) has been demonstrated by numerous studies and is particularly important for head and neck cancer (HNC) treatment due to the complexity of RT target volumes in this region and the multiple adjacent organs at risk. The RT planning process includes many critical steps including interpretation of diagnostic imaging, image fusion, target volume delineation (tumor, lymph nodes, and organs at risk), and planning. Each step has become highly complex, and precise and rigorous QA throughout the planning process is essential. The ultimate aim is to precisely deliver radiation dose to the target, maximizing the tumor dose and minimizing the dose to surrounding organs at risk, in order to improve the therapeutic index. It is imperative that RT QA programs should systematically control all aspects of the RT planning pathway and include regular end-to-end tests and external audits. However, comprehensive QA should not be limited to RT and should, where possible, also be implemented for surgery, systemic therapy, pathology, as well as other aspects involved in the interdisciplinary treatment of HNC.
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Project description:In this study, we present an intensity-modulated radiotherapy technique based on forward planning dose calculations to provide a concave dose distribution to the prostate and seminal vesicles by means of modified dynamic arc therapy (M-DAT). Dynamic arcs (350 degrees) conforming to the beam's eye view of the prostate and seminal vesicles while shielding the rectum, combined with two lateral oblique conformal fields (15 degrees with respect to laterals) fitting the prostate only,were applied to deliver doses of 78 Gy and 61.23 Gy in 39 fractions to the prostate and seminal vesicles respectively. Dynamic wedges (45 degrees of thick end, anteriorly oriented) were used with conformal beams to adjust the dose homogeneity to the prostate, although in some cases, hard wedges (30 degrees of thick part,inferiorly oriented) were used with arcs to adjust the dose coverage to the seminal vesicles. The M-DAT was applied to 10 patients in supine and 10 patients in prone positioning to determine the proper patient positioning for optimum protection of the rectum. The M-DAT was compared with the simplified intensity-modulated arc therapy (SIMAT) technique, composed of three phases of bilateral dynamic arcs. The mean rectal dose in M-DAT for prone patients was 22.5 +/- 5.1 Gy; in M-DAT and SIMAT for supine patients, it was 30.2 +/- 5.1 Gy and 39.4 +/- 6.0 Gy respectively. The doses to 15%, 25%, 35%, and 50% of the rectum volume in M-DAT for prone patients were 44.5 +/- 10.2 Gy, 33.0 +/- 8.2 Gy, 25.3 +/- 6.4 Gy, and 16.3 +/- 5.6 Gy respectively. These values were lower than those in M-DAT and in SIMAT for supine patients by 7.7%, 18.2%, 22.4%, and 28.5% and by 25.0%, 32.1%, 34.9%, and 41.9% of the prescribed dose (78 Gy) respectively. Ion chamber measurements showed good agreement of the calculated and measured isocentric dose (maximum deviation of 3.5%). Accuracy of the dose distribution calculation was evaluated by film dosimetry using a gamma index, allowing 3% dose variation and 4 mm distance to agreement as the individual acceptance criteria in prostate and seminal vesicle levels alike for all supine and prone patients. We found that fewer than 10% of the pixels in the dose distribution of the calculated area of10 x 10-cm failed the acceptance criteria. These pixels were observed mainly in the low-dose regions, particularly at the level of the seminal vesicles. In conclusion, the single-phase M-DAT technique with patients in the prone position was found to provide the intended coverage of the prescribed doses to the prostate and seminal vesicles with improved protection for the rectum. Accordingly, M-DAT has replaced non-modulated conformal radiotherapy or SIMAT as the standard treatment for prostate cancer in our department.
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Project description:Patients undergoing intensity-modulated radiotherapy (IMRT) for head and neck cancer may have increased incidence of dry eye disease and the exact mechanism is unclear. The present study aims to assess tear film and meibomian gland (MG) features in patients who received IMRT for head and neck cancer not involving the orbital area. Twenty-seven patients (64.7 ± 9.8 years) and 30 age-matched controls (61.4 ± 11.0 years) underwent a comprehensive dry eye work-up. Compared to the control group, the patients had more lid margin abnormalities, and worse meibum quality. The MG loss, calculated as (tarsal area-MG area)/tarsal area, was higher in the patient group in both the upper (53.0 ± 12.0% vs. 35.1 ± 10.3%, p < 0.001) and lower lids (69.5 ± 12.6% vs. 48.5 ± 12.5%, p < 0.001). In the patient group, more MG loss in the lower lids correlated with worse meibum quality (r = 0.445, p = 0.029). In contrast, there was no significant difference in aqueous tear production level, measured with Schirmer test. Patients treated with IMRT for head and neck cancer seemed to have comparable lacrimal gland function to the controls despite more dry eye symptoms. However, the patients had MG functional and morphological changes, which may present a higher risk for developing dry eye disease.
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Project description:ImportanceThe majority of the patients with head and neck cancer (HNC) experience taste dysfunction (TD) during or after radiotherapy (RT). However, prospectively collected data for taste dysfunction have been limited, especially in the era of intensity-modulated RT (IMRT).ObjectiveTo evaluate the taste function in patients with HNC receiving IMRT by investigating the association between time course and recovery of TD in both acute and late phases.Design, setting, and participantsFrom August 2017 to November 2020, patients treated at the Chang Gung Memorial Hospital with curative or postoperative IMRT for HNC were enrolled in this prospective cohort study. The data analysis was performed from March 2021 to January 2022.ExposuresIMRT with and without concurrent chemotherapy.Main outcomes and measuresTaste function was measured using the whole-mouth solution method for 4 tastes (salt, sweet, sour, and bitter). Subjective evaluations (National Cancer Institute Common Terminology Criteria for Adverse Events [version 4.03] and Subjective Total Taste Acuity scale) were used. Patient self-reported quality of life was evaluated using European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Head and Neck Module (EORTC QLQ-H&N35).ResultsA total of 87 patients (78 [90%] men and 9 [10%] women; mean [range] age, 58 [31-80] years) were enrolled. Overall TD rates were 79 of 86 (91.9%), 63 of 83 (75.9%), 27 of 81 (33.3%), 5 of 56 (8.9%), and 2 of 30 (6.7%) during RT, and 1 week, 3 months, 6 months, and 1 year after RT, respectively. Positive correlation occurred between objectively measured taste loss for the 4 taste qualities and subjective perception of taste loss. Only oral cavity mean dose 4000 cGy or greater predicted TD 3 months after RT. The mean oral cavity doses to the predicted 15% (D15), 25% (D25), and 50% (D50) probabilities were 25, 38, and 60 Gy at 3 months and 57, 60, and 64 Gy at 6 months, respectively.Conclusions and relevanceIn this cohort study, most patients still experienced TD during and at 3 months after RT. Only a few patients experienced long-term TD. A high oral cavity dose was associated with TD in patients with HNC receiving IMRT. Reducing oral cavity dose may promote early recovery of taste function after IMRT.
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