Implications of improved diagnostic imaging of small nodal metastases in head and neck cancer: Radiotherapy target volume transformation and dose de-escalation.

Diagnostic imaging continues to evolve, and now has unprecedented accuracy for detecting small nodal metastasis. This influences the tumor load in elective target volumes and subsequently has consequences for the radiotherapy dose required to control disease in these volumes. Small metastases that used to remain subclinical and were included in elective volumes, will nowadays be detected and included in high-dose volumes.

Detection of cartilage invasion in laryngeal carcinoma with dynamic contrast-enhanced CT.

Objective: Staging of laryngeal cancer largely depends on cartilage invasion. Presence of cartilage invasion affects treatment choice and prognosis. On MRI and contrast-enhanced CT (CECT) it may be challenging to differentiate cartilage invasion from inflammation.

Uniform FDG-PET guided GRAdient Dose prEscription to reduce late Radiation Toxicity (UPGRADE-RT): study protocol for a randomized clinical trial with dose reduction to the elective neck in head and neck squamous cell carcinoma.

Background: In definitive radiation therapy for head and neck cancer, clinically uninvolved cervical lymph nodes are irradiated with a so-called 'elective dose' in order to achieve control of clinically occult metastases. As a consequence of high-resolution diagnostic imaging, occult tumor volume has significantly decreased in the last decades. Since the elective dose is dependent on occult tumor volume, the currently used elective dose may be higher than necessary.

Modality-specific target definition for laryngeal and hypopharyngeal cancer on FDG-PET, CT and MRI.

Background And Purpose: The goal of this study was to improve target definition by deriving modality-specific margins for clinical target volumes (CTV) for laryngeal and hypopharyngeal cancer on CT, MRI and 18-FDG-PET.

Material And Methods: Twenty-five patients with T3/T4 laryngeal/hypopharyngeal cancer underwent CT, MRI and 18-FDG-PET scans before laryngectomy. HE-sections were obtained from the surgical specimen and tumor was delineated (tumor).

Validated guidelines for tumor delineation on magnetic resonance imaging for laryngeal and hypopharyngeal cancer.

Background: Validation of magnetic resonance imaging (MRI) and development of guidelines for the delineation of the gross tumor volume (GTV) is of utmost importance to benefit from the visibility of anatomical details on MR images and to achieve an accurate GTV delineation. In the ideal situation, the GTV delineation corresponds to the histopathologically determined 'true tumor volume'. Consequently, we developed guidelines for GTV delineation of laryngeal and hypopharyngeal tumors on MRI and determined the accuracy of the resulting delineation of the tumor outline on histopathology as gold standard.

The accuracy of target delineation in laryngeal and hypopharyngeal cancer.

Background And Purpose: To determine the spatial correspondence between the gross tumor volume (GTV) delineated on computer tomography (CT) and the actual tumor on histopathology.

Material And Methods: Sixteen patients with T3 or T4 laryngeal or hypopharyngeal cancer underwent a CT scan before total laryngectomy. The GTV was delineated on CT by three independent observers and by consensus between the three observers.

GTV delineation in supraglottic laryngeal carcinoma: interobserver agreement of CT versus CT-MR delineation.

Background: GTV delineation is the first crucial step in radiotherapy and requires high accuracy, especially with the growing use of highly conformal and adaptive radiotherapy techniques. If GTV delineations of observers concord, they are considered to be of high accuracy. The aim of the study is to determine the interobserver agreement for GTV delineations of supraglottic laryngeal carcinoma on CT and on CT combined with MR-images and to determine the effect of adding MR images to CT-based delineation on the delineated volume and the interobserver agreement.

Consequences of tumor planning target volume reduction in treatment of T2-T4 laryngeal cancer.

Background And Purpose: Since lymph nodes volumes are generally four times the volume of the primary PTV, the advantage of using tight margins around the primary PTV is not clear. Therefore treatment margins of T2-T4 laryngeal carcinoma for IMRT are generally chosen in such a way that the PTV is comparable to that in conventional radiotherapy. The aim of this study is to quantify the effect of volume reduction of the primary PTV of T2-T4 laryngeal carcinoma with regard to late toxicity despite elective irradiation of lymph node levels II to IV.

Xerostomia: a day and night difference.

Purpose: To compare patient-reported xerostomia during daytime and during nighttime with objectively measured parotid and submandibular gland function in a cohort of head-and-neck cancer (HNC) patients treated with RT.

Materials And Methods: A cohort of 138 HNC patients underwent objective measurements of parotid (PF) and submandibular (SMF) gland function and completed a xerostomia questionnaire (XQ) before RT, at 6 weeks, 6 months and 1 year after RT. No attempt was made to spare the submandibular gland(s).

MUC5B levels in submandibular gland saliva of patients treated with radiotherapy for head-and-neck cancer: a pilot study.

Background: The salivary mucin MUC5B, present in (sero)mucous secretions including submandibular gland (SMG) saliva, plays an important role in the lubrication of the oral mucosa and is thought to be related to the feeling of dry mouth. We investigated if MUC5B levels in SMG saliva could distinguish between the presence or absence of severe dry mouth complaints 12  months after radiotherapy (RT) for head-and-neck cancer (HNC).

Findings: Twenty-nine HNC patients with a residual stimulated SMG secretion rate of ≥ 0.

Origin of tumor recurrence after intensity modulated radiation therapy for oropharyngeal squamous cell carcinoma.

Purpose: To model locoregional recurrences of oropharyngeal squamous cell carcinomas (OSCC) treated with primary intensity modulated radiation therapy (IMRT) in order to find the origins from which recurrences grow and relate their location to original target volume borders.

Methods And Materials: This was a retrospective analysis of OSCC treated with primary IMRT between January 2002 and December 2009. Locoregional recurrence volumes were delineated on diagnostic scans and coregistered rigidly with treatment planning computed tomography scans.

MRI to quantify early radiation-induced changes in the salivary glands.

Purpose: We investigated radiation-induced changes in the salivary glands, 6 weeks after RT, using MRI.

Materials And Methods: Eighteen oropharyngeal cancer patients were treated with salivary gland sparing IMRT. All patients received a 3T MRI exam before and 6 weeks after the end of RT, including a T(1)-weighted (T(1)w), a T(2)-weighted (T(2)w), and a dynamic contrast-enhanced (DCE) MRI.

Validation of imaging with pathology in laryngeal cancer: accuracy of the registration methodology.

Purpose: To investigate the feasibility and accuracy of an automated method to validate gross tumor volume (GTV) delineations with pathology in laryngeal and hypopharyngeal cancer.

Methods And Materials: High-resolution computed tomography (CT(HR)), magnetic resonance imaging (MRI), and positron emission tomography (PET) scans were obtained from 10 patients before total laryngectomy. The GTV was delineated separately in each imaging modality.

Magnetic resonance imaging at 3.0T for submandibular gland sparing radiotherapy.

Purpose: Besides sparing the parotid gland, sparing the submandibular gland is considered to be important in preventing xerostomia in head-and-neck cancer patients. Delineation of the submandibular gland at CT, and even on T(1)- and T(2)-weighted MR images, is difficult, due to low contrast with the surrounding tissues. MR sialography might be used for delineation.

Improved immobilization using an individual head support in head and neck cancer patients.

The benefits of a patient-specific head support, developed to improve immobilization during radiotherapy, were determined in head and neck cancer patients. Cone-beam CTs were registered to the planning CT in five regions. Compared to the standard head support, the individual head support decreased the systematic and random errors of the inter- and intrafraction displacements and reduced deformations.

Parotid gland function after radiotherapy: the combined michigan and utrecht experience.

Purpose: To analyze the combined and updated results from the University of Michigan and University Medical Center Utrecht on normal tissue complication probability (NTCP) of the parotid gland 1 year after radiotherapy (RT) for head-and-neck (HN) cancer.

Patients And Methods: A total of 222 prospectively analyzed patients with various HN malignancies were treated with conventional and intensity-modulated RT. Stimulated individual parotid gland flow rates were measured before RT and 1 year after RT using Lashley cups at both centers.

A comparison of dose-response models for the parotid gland in a large group of head-and-neck cancer patients.

Purpose: The dose-response relationship of the parotid gland has been described most frequently using the Lyman-Kutcher-Burman model. However, various other normal tissue complication probability (NTCP) models exist. We evaluated in a large group of patients the value of six NTCP models that describe the parotid gland dose response 1 year after radiotherapy.

Magnetic resonance imaging protocol optimization for delineation of gross tumor volume in hypopharyngeal and laryngeal tumors.

Purpose: To optimize the use of MRI for delineation of gross tumor volume for radiotherapy treatment planning purposes in hypopharyngeal and laryngeal tumors.

Methods And Materials: Magnetic resonance images (T1 weighted and T2 weighted) of a healthy volunteer were acquired using a 1.5 T and 3.

Sparing the contralateral submandibular gland in oropharyngeal cancer patients: a planning study.

Background And Purpose: The submandibular glands are proposed to be important in preventing xerostomia in head-and-neck cancer patients. We investigated the feasibility of sparing the contralateral submandibular gland (cSMG) by reducing the dose to the contralateral planning target volume (PTV) and by reducing the clinical target volume (CTV)-to-PTV margin.

Materials And Methods: Ten oropharyngeal cancer patients with a contralateral elective PTV were included in this planning study, using intensity modulated radiotherapy (IMRT).

Large cohort dose-volume response analysis of parotid gland function after radiotherapy: intensity-modulated versus conventional radiotherapy.

Purpose: To compare parotid gland dose-volume response relationships in a large cohort of patients treated with intensity-modulated (IMRT) and conventional radiotherapy (CRT).

Methods And Materials: A total of 221 patients (64 treated with IMRT, 157 with CRT) with various head-and-neck malignancies were prospectively evaluated. The distribution of tumor subsites in both groups was unbalanced.

3D MR sialography as a tool to investigate radiation-induced xerostomia: feasibility study.

Purpose: To evaluate whether magnetic-resonance (MR) sialography can be used to investigate radiation-induced xerostomia. Preradiotherapy (pre-RT) and postradiotherapy (post-RT) MR sialographic images of the major salivary ducts (parotid and submandibular) were compared.

Methods And Materials: Magnetic-resonance sialography was performed pre-RT, and 6 weeks and 6 months post-RT on 9 patients with T1-4N0-2M0 naso- or oropharyngeal tumors, on a 1.

Cranial location of level II lymph nodes in laryngeal cancer: Implications for elective nodal target volume delineation.

Purpose: To analyze the cranial distribution of level II lymph nodes in patients with laryngeal cancer to optimize the elective radiation nodal target volume delineation.

Methods And Materials: The most cranially located metastatic lymph node was delineated in 67 diagnostic CT data sets. The minimum distance from the base of the skull (BOS) to the lymph node was determined.

Quality of life and salivary output in patients with head-and-neck cancer five years after radiotherapy.

Background: To describe long-term changes in time of quality of life (QOL) and the relation with parotid salivary output in patients with head-and-neck cancer treated with radiotherapy.

Methods: Forty-four patients completed the EORTC-QLQ-C30(+3) and the EORTC-QLQ-H&N35 questionnaires before treatment, 6 weeks, 6 months, 12 months, and at least 3.5 years after treatment.