The impact of treatment on health related quality of life in head and neck cancer

Background: Head and neck cancer is a rare form of cancer and approximately 1000 new cases are diagnosed in Sweden each year. It is more common in men than in women, and treatment includes surgery and/or radiotherapy (both external radiotherapy and/or brachytherapy) + chemotherapy. Five-year survival is about 60 % and morbidity due to treatment is high in the advanced stages.During the last decades health related quality of life (HRQL) has evolved as a new endpoint in evaluating treatment. The most common way to assess HRQL is by quality of life questionnaires. The European Organization for Research and Treatment of Cancer (EORTC) has developed, and validated several HRQL questionnaires, for instance the cancer specific questionnaire (EORTC QLQ-C30) and the head and neck cancer specific questionnaire (EORTC QLQ-H&N35). Methods: HRQL was assessed with the aid of the questionnaires EORTC QLQ-C30, EORTC QLQ-H&N35 and the hospital anxiety and depression scale (HADS), at diagnosis, and 1, 2, 3, 6, 12, 36 months after treatment start. In this thesis HRQL was longitudinally assessed in head and neck patients offered psychosocial support, in head and neck cancer patients with severe weight loss during treatment, and in patients with oral and oropharyngeal cancer.Results: The support had no detectable effect on HRQL, compared to a control group. Pre-treatment HRQL scores could predict weight loss. Patients who reported increased sensation of fatigue at diagnosis developed more then 10% weight loss during treatment. Advanced oral and oropharyngeal cancer (stage III-IV) patients had similar HRQL whether they were treated with a lower external radiotherapy (ERT) dose, and a higher brachytherapy (BT) dose or a higher ERT dose, and lower BT dose. No correlation could be found between HRQL scores and BT dose, and dose rate in patients with stage I-IV oral, and oropharyngeal cancer.Conclusion: In this thesis the impact of treatment in head and neck cancer has been evaluated with HRQL questionnaires. Conclusions drawn are that supporting patients does not appear to affect HRQL, and that those prone to weight loss can be detected already at diagnosis with HRQL questionnaires. Treating advanced oral and oropharyngeal cancer with a lower ERT dose, and a higher BT dose, does not appear to jeopardize HRQL

Structure delineation in the presence of metal – A comparative phantom study using single and dual-energy computed tomography with and without metal artefact reduction

Background and purpose: Metal artefacts in computed tomography (CT) images impairs structure delineation. These artefacts can potentially be reduced with dual-energy CT (DECT) with or without using metal artefact reduction (MAR). The purpose was to investigate how structure delineation in DECT with or without MAR and single-energy CT (SECT) images were affected by metals. Materials and methods: A phantom with known irregular structures was developed. Reference structures were determined from a low-noise scan without metal. Bilateral hip prostheses were simulated with steel or titanium inserts. The phantom was scanned with SECT and fast-kV switching DECT with optional MAR. Four radiation oncologists delineated the structures in two phantom set-ups. Delineated structures were evaluated with Dice similarity coefficient (DSC) and Hausdorff distance relative to the reference structures. Results: With titanium inserts, more structures were detected for non-MAR DECT compared to SECT while the same or less were detected with steel inserts. MAR improved delineation in DECT images. For steel inserts, three structures in the region of artefacts, were delineated by at least two oncologists with MAR-DECT compared to none with non-MAR DECT or SECT. The highest values of DSC for MAR-DECT were 0.69, 0.81 and 0.77 for those structures. Conclusions: Delineation was improved with non-MAR DECT compared to SECT, especially for titanium inserts. A larger improvement was seen with the use of MAR for both steel and titanium inserts. The improvement was dependent on the location of the structure relative to the inserts, and the structure contrast relative to the background. Keywords: Radiotherapy, Treatment planning, Computed tomography, Delineation uncertainty, Dual-energy computed tomography, Metal artefact reductio

Synthetic computed tomography data allows for accurate absorbed dose calculations in a magnetic resonance imaging only workflow for head and neck radiotherapy

Background and purpose: Few studies on magnetic resonance imaging (MRI) only head and neck radiation treatment planning exist, and none using a generally available software. The aim of this study was to evaluate the accuracy of absorbed dose for head and neck synthetic computed tomography data (sCT) generated by a commercial convolutional neural network-based algorithm. Materials and methods: For 44 head and neck cancer patients, sCT were generated and the geometry was validated against computed tomography data (CT). The clinical CT based treatment plan was transferred to the sCT and recalculated without re-optimization, and differences in relative absorbed dose were determined for dose-volume-histogram (DVH) parameters and the 3D volume. Results: For overall body, the results of the geometric validation were (Mean ± 1sd): Mean error −5 ± 10 HU, mean absolute error 67 ± 14 HU, Dice similarity coefficient 0.98 ± 0.05, and Hausdorff distance difference 4.2 ± 1.7 mm. Water equivalent depth difference for region Th1-C7, mid mandible and mid nose were −0.3 ± 3.4, 1.1 ± 2.0 and 0.7 ± 3.8 mm respectively. The maximum mean deviation in absorbed dose for all DVH parameters was 0.30% (0.12 Gy). The absorbed doses were considered equivalent (p-value < 0.001) and the mean 3D gamma passing rate was 99.4 (range: 95.7–99.9%). Conclusions: The convolutional neural network-based algorithm generates sCT which allows for accurate absorbed dose calculations for MRI-only head and neck radiation treatment planning. The sCT allows for statistically equivalent absorbed dose calculations compared to CT based radiotherapy

MR-OPERA : a multicenter/multivendor validation of magnetic resonance imaging–only prostate treatment planning using synthetic computed tomography images

Purpose: To validate the dosimetric accuracy and clinical robustness of a commercially available software for magnetic resonance (MR) to synthetic computed tomography (sCT) conversion, in an MR imaging–only workflow for 170 prostate cancer patients. Methods and Materials: The 4 participating centers had MriPlanner (Spectronic Medical), an atlas-based sCT generation software, installed as a cloud-based service. A T2-weighted MR sequence, covering the body contour, was added to the clinical protocol. The MR images were sent from the MR scanner workstation to the MriPlanner platform. The sCT was automatically returned to the treatment planning system. Four MR scanners and 2 magnetic field strengths were included in the study. For each patient, a CT-treatment plan was created and approved according to clinical practice. The sCT was rigidly registered to the CT, and the clinical treatment plan was recalculated on the sCT. The dose distributions from the CT plan and the sCT plan were compared according to a set of dose-volume histogram parameters and gamma evaluation. Treatment techniques included volumetric modulated arc therapy, intensity modulated radiation therapy, and conventional treatment using 2 treatment planning systems and different dose calculation algorithms. Results: The overall (multicenter/multivendor) mean dose differences between sCT and CT dose distributions were below 0.3% for all evaluated organs and targets. Gamma evaluation showed a mean pass rate of 99.12% (0.63%, 1 SD) in the complete body volume and 99.97% (0.13%, 1 SD) in the planning target volume using a 2%/2-mm global gamma criteria. Conclusions: Results of the study show that the sCT conversion method can be used clinically, with minimal differences between sCT and CT dose distributions for target and relevant organs at risk. The small differences seen are consistent between centers, indicating that an MR imaging–only workflow using MriPlanner is robust for a variety of field strengths, vendors, and treatment techniques