Patterns of long-term swallowing dysfunction after definitive radiotherapy or chemoradiation

Objectives: To identify patterns of long-term, radiation-induced swallowing dysfunction after definitive radiotherapy with or without chemotherapy (RT or CHRT) and to determine which factors may explain these patterns over time.Material and methods: The study population consisted of 238 consecutive head and neck cancer patients treated with RT or CHRT. The primary endpoint was &gt;= grade 2 swallowing dysfunction at 6, 12, 18 and 24 months after treatment. Cluster analysis was used to identify different patterns over time. The differences between the mean dose to the swallowing organs at risk for each pattern were determined by using dose maps.Results: The cluster analysis revealed five patterns of swallowing dysfunction: low persistent, intermediate persistent, severe persistent, transient and progressive. Patients with high dose to the upper pharyngeal, laryngeal and lower pharyngeal region had the highest risk of severe persistent swallowing dysfunction. Transient problems mainly occurred after high dose to the laryngeal and lower pharyngeal regions, combined with moderate dose to the upper pharyngeal region. The progressive pattern was mainly seen after moderate dose to the upper pharyngeal region.Conclusions: Various patterns of swallowing dysfunction after definitive RT or CHRT can be identified over time. This could reflect different underlying biological processes. (C) 2015 The Authors. Published by Elsevier Ireland Ltd.</p

On the practice of the clinical implementation of enhanced dynamic wedges

Practical aspects of the clinical implementation of enhanced dynamic wedges (EDW) replacing manual wedges are presented and discussed extensively. A comparison between measured and calculated data is also presented. Relative dose distributions and wedge factors were calculated with a commercially available treatment planning system and measured in a water-phantom and with an ionization chamber. Wedge factor calculations and measurements were also compared with an independent method of wedge factor calculations available from the literature. Aspects of the clinical implementation, such as safety and quality assurance, were evaluated. Measurements and calculations agreed very well and were slightly better than results of previous studies. Profiles and percentage depth doses (PDDs) agreed within 1% to 1.5% and within 0.5%, respectively. Measured and calculated wedge factors ratios agreed within 0.5% to 1%. Calculated and measured EDW dose distributions showed excellent agreement, both relative and absolute. However, for safe and practical use, specific aspects need to be taken into consideration. Once the treatment planning system is commissioned properly, the clinical implementation of EDW is rather straightforward

Total Body Irradiation and Total Skin Irradiation Techniques in Belgium and the Netherlands: Current Clinical Practice

Purpose: In 2014, a Belgian/Dutch Nederlandse Commissie voor Stralingsdosimetrie (NCS) task group was formed to develop guidelines on the clinical practice of total body irradiation (TBI) and total skin irradiation (TSI). Methods and Materials: As a basis for these guidelines, a survey conducted among 17 Belgian and Dutch radiation oncology institutions measured the clinical practice of TBI. Four of these institutions also performed TSI. An update was performed in 2019 and 2020 because several institutions innovated their TBI techniques. Results: As old and more recent studies have shown, clinical protocols for TBI and TSI still vary considerably between institutions. Conclusions: New radiation therapy technologies have been introduced relatively slowly for TBI purposes

Interoperabiliteit in de radiotherapie in Nederland

Interoperabiliteit is het vermogen van informatiesystemen om samen te werken binnen en buiten de grenzen van de organisatie. Binnen de gezondheidszorg betreft het dan ondersteuning van een effectieve zorg. Vanwege de snelle technologische ontwikkelingen en de toenemende complexiteit van de communicatie is de verwachting dat aan interoperabiliteit gerelateerde problemen steeds zichtbaarder en merkbaarder worden. Dit is ook bij radiotherapie het geval. Daarnaast is in Nederland een trend gaande van radiotherapie afdelingen die groeien naar multi-locatie afdelingen. De voorbereidingen door de afdeling radiotherapie van het VUmc voor haar satellietlocatie waren de aanleiding om in 2010 te starten met een onderzoek naar interoperabiliteitsproblemen binnen het vakgebied radiotherapie. Hiervoor is een enquête gehouden onder alle afdelingen radiotherapie in Nederland. Meer informatie is verkregen door interviews op vier radiotherapie afdelingen. Op de afdeling radiotherapie van het VUmc is een casus studie uitgevoerd, waarbij de bedrijfsprocessen en informatiestromen werden gemodelleerd. Geïdentificeerde interoperabiliteitsproblemen zijn geanalyseerd en aanbevelingen ter verbetering zijn gedaan. De bevindingen zijn dat de technische interoperabiliteitsproblemen zeldzaam zijn en dat ze meestal op strategisch en semantisch niveau optreden, dat wil zeggen de eenduidigheid van de berichten structuur en de juiste interpretatie van van de informatie. Voor de afdeling radiotherapie van het VUmc zijn geen grote nieuwe interoperabiliteitsproblemen te verwachten in de groei naar een multi-locatie afdeling. Verwacht wordt dat de meeste problemen zullen worden gedekt door bestaande of toekomstige integratieprofielen van 'Integrating the Healthcare Enterprise'

The use of a wearable cardioverter defibrillator during postmastectomy radiotherapy as an alternative for relocation of the pulse generator

Purpose: We describe a case in which a breast cancer patient with an implantable cardioverter-defibrillator (ICD) was treated with postmastectomy followed by axillary radiation therapy. The ICD was partly within the target volume and according to the treatment planning system would receive a maximum dose of about 36 Gy. Methods and Materials: Postoperatively, the patient had a wound infection needing surgical intervention and 3 months of antibiotics. Therefore, it was decided not to relocate the ICD but instead to switch off the shock function of the ICD for the entire radiation therapy course. Results: The ICD was successfully substituted with a wearable cardioverter defibrillator (WCD), which the patient wore during the 3-week radiation therapy period until 2 weeks after the end of treatment. The ICD function was monitored from the start of the treatment until 6 months after treatment. Conclusions: In situations in which an ICD needs to be switched off semipermanently, a WCD can be used as alternative. The patient in this report tolerated the WCD well. Despite the high dose received by the ICD, the device and its battery continued to function normally

Predictive modelling for swallowing dysfunction after primary (chemo)radiation: Results of a prospective observational study

BACKGROUND AND PURPOSE: The purpose of this large multicentre prospective cohort study was to identify which dose volume histogram parameters and pre-treatment factors are most important to predict physician-rated and patient-rated radiation-induced swallowing dysfunction (RISD) in order to develop predictive models for RISD after curative (chemo) radiotherapy ((CH) RT). MATERIAL AND METHODS: The study population consisted of 354 consecutive head and neck cancer patients treated with (CH) RT. The primary endpoint was grade 2 or more swallowing dysfunction according to the RTOG/EORTC late radiation morbidity scoring criteria at 6months after (CH) RT. The secondary endpoints were patient-rated swallowing complaints as assessed with the EORTC QLQ-H&N35 questionnaire. To select the most predictive variables a multivariate logistic regression analysis with bootstrapping was used. RESULTS: At 6months after (CH) RT the bootstrapping procedure revealed that a model based on the mean dose to the superior pharyngeal constrictor muscle (PCM) and mean dose to the supraglottic larynx was most predictive. For the secondary endpoints different predictive models were found: for problems with swallowing liquids the most predictive factors were the mean dose to the supraglottic larynx and radiation technique (3D-CRT versus IMRT). For problems with swallowing soft food the mean dose to the middle PCM, age (18-65 versus >65years), tumour site (naso/oropharynx versus other sites) and radiation technique (3D-CRT versus IMRT) were the most predictive factors. For problems with swallowing solid food the most predictive factors were the mean dose to the superior PCM, the mean dose to the supraglottic larynx and age (18-65 versus >65years). And for choking when swallowing the V60 of the oesophageal inlet muscle and the mean dose to the supraglottic larynx were the most predictive factors. CONCLUSIONS: Physician-rated and patient-rated RISD in head and neck cancer patients treated with (CH) RT cannot be predicted with univariate relationships between the dose distribution in a single organ at risk and an endpoint. Separate predictive models are needed for different endpoints and factors other than dose volume histogram parameters are important as well

Development of NTCP models for head and neck cancer patients treated with three-dimensional conformal radiotherapy for xerostomia and sticky saliva: The role of dosimetric and clinical factors

PURPOSE: The purpose of this multicentre prospective study was to investigate the significance of the radiation dose in the major and minor salivary glands, and other pre-treatment and treatment factors, with regard to the development of patient-rated xerostomia and sticky saliva among head and neck cancer (HNC) patients treated with primary (chemo-) radiotherapy ((CH)RT). METHODS AND MATERIALS: The study population was composed of 167 consecutive HNC patients treated with three-dimensional conformal (3D-CRT) (CH) RT. The primary endpoint was moderate to severe xerostomia (XER6m) as assessed by the EORTC QLQ-H&N35 at 6months after completing (CH)RT. The secondary endpoint was moderate to severe sticky saliva at 6months (STIC6m). All organs at risk (OARs) potentially involved in salivary function were delineated on planning-CT, including the parotid, submandibular and sublingual glands and the minor glands in the soft palate, cheeks and lips. Patients with moderate to severe xerostomia or sticky saliva at baseline were excluded. The optimum number of variables for a multivariate logistic regression model was determined using a bootstrapping method. RESULTS: The multivariate analysis showed the mean parotid dose, age and baseline xerostomia (none versus a bit) to be the most important predictors for XER6m. The risk of developing xerostomia increased with age and was higher when minor baseline xerostomia was present in comparison with patients without any xerostomia complaints at baseline. Model performance was good with an area under the curve (AUC) of 0.82. For STIC6m, the mean submandibular dose, age, the mean sublingual dose and baseline sticky saliva (none versus a bit) were most predictive for sticky saliva. The risk of developing STIC6m increased with age and was higher when minor baseline sticky saliva was present in comparison with patients without any sticky saliva complaints at baseline. Model performance was good with an AUC of 0.84. CONCLUSIONS: Dose distributions in the minor salivary glands in patients receiving 3D-CRT have limited significance with regard to patient-rated symptoms related to salivary dysfunction. Besides the parotid and submandibular glands, only the sublingual glands were significantly associated with sticky saliva. In addition, reliable risk estimation also requires information from other factors such as age and baseline subjective scores. When these selected factors are included in predictive models, instead of only dose volume histogram parameters, model performance can be improved significantly