J.A. Langendijk

A predictive model for swallowing dysfunction after curative radiotherapy in head and neck cancer

INTRODUCTION Recently, we found that swallowing dysfunction after curative (chemo) radiation (CH) RT has a strong negative impact on health-related quality of life (HRQoL), even more than xerostomia. The purpose of this study was to design a predictive model for swallowing dysfunction after curative radiotherapy or chemoradiation. MATERIALS AND METHODS A prospective study was performed including 529 patients with head and neck squamous cell carcinoma (HNSCC) treated with curative (CH) RT. In all patients, acute and late radiation-induced morbidity (RTOG Acute and Late Morbidity Scoring System) was scored prospectively. To design the model univariate and multivariate logistic regression analyses were carried out with grade 2 or higher RTOG swallowing dysfunction at 6 months as the primary (SWALL(6months)) endpoint. The model was validated by comparing the predicted and observed complication rates and by testing if the model also predicted acute dysphagia and late dysphagia at later time points (12, 18 and 24 months). RESULTS After univariate and multivariate logistic regression analyses, the following factors turned out to be independent prognostic factors for SWALL(6months): T3-T4, bilateral neck irradiation, weight loss prior to radiation, oropharyngeal and nasopharyngeal tumours, accelerated radiotherapy and concomitant chemoradiation. By summation of the regression coefficients derived from the multivariate model, the Total Dysphagia Risk Score (TDRS) could be calculated. In the logistic regression model, the TDRS was significantly associated with SWALL(6months) ((p<0.001). Subsequently, we defined three risk groups based on the TDRS. The rate of SWALL(6months) was 5%, 24% and 46% in case of low-, intermediate- and high-risk patients, respectively. These observed percentages were within the 95% confidence intervals of the predicted values. The TDRS risk group classification was also significantly associated with acute dysphagia (P<0.001 at all time points) and with late swallowing dysfunction at 12, 18 and 24 months (p<0.001 at all time points). CONCLUSION The TDRS is a simple and validated measure to predict swallowing dysfunction after curative (CH) RT for HNC. This classification system enables identification of patients who may benefit from strategies aiming at prevention of swallowing dysfunction after curative (CH) RT such as preventive swallowing exercises during treatment and/or emerging IMRT techniques aiming at sparing anatomical structures that are involved in swallowing.

Cordectomy by CO2 laser or radiotherapy for small T1a glottic carcinomas: Costs, local control, survival, quality of life, and voice quality

The clinical results of radiotherapy and endoscopic cordectomy for T1a glottic carcinoma are reported to be similar, but costs of both treatments may differ. Therefore, we retrospectively evaluated the costs, voice quality, quality of life, and clinical results of both treatments.

Swallowing after major surgery of the oral cavity or oropharynx: a prospective and longitudinal assessment of patients treated by microvascular soft tissue reconstruction.

The aim of this study was to analyze swallowing outcome in advanced oral/oropharyngeal cancer patients treated with microvascular reconstructive surgery and adjuvant radiotherapy.

Postoperative radiotherapy in squamous cell carcinoma of the oral cavity: The importance of the overall treatment time

PURPOSE To test the hypothesis that (1) the distinction between intermediate- and high-risk patients by clustering different prognostic factors results in a significant difference in treatment outcome and (2) a shorter interval between surgery and radiotherapy and shorter overall treatment times of radiation (OTTRT) result in higher rates of locoregional control (LRC). METHODS AND MATERIALS Included were patients (n = 217) with previously untreated squamous cell carcinoma of the oral cavity treated with radical surgery and postoperative radiotherapy. Patients with extranodal spread or microscopic residual disease and patients with two or more other risk factors (i.e., N2b-N3, >1 nodal level involved, perineural growth, or stage T3-T4) were classified as high-risk patients. Patients with only one other risk factor were classified as intermediate risk. RESULTS In the intermediate-risk group, the 3-year LRC was 87% as compared with 66% in the high-risk group (p = 0.0005). No association was found between interval and LRC. However, the OTTRT was significantly associated with LRC. The 3-year LRC was 87%, 75%, 69%, and 51% when the OTT was <6 weeks, 6-7 weeks, 7-8 weeks, and >8 weeks, respectively (p = 0.0004). The 3-year overall survival (OS) in the intermediate risk patients was 74% compared with 50% in the high-risk group (p = 0.0014). A significant association was also found between the OS and OTTRT. The OS increased from 50% when the OTTRT was >8 weeks to 74% when the OTT was <6 weeks (p = 0.006). Similar results were found with regard to the disease-free survival (DFS). In the multivariate analysis, both risk group and OTT were significantly associated with LRC, DFS, and OS. No significant interaction term was present between these two factors, which means that the OTT was of importance both for the high-risk and the intermediate-risk patients. CONCLUSION In the subset of patients with carcinoma of the oral cavity, the classification of high- and intermediate-risk patients by clustering a number of prognostic factors provides important prognostic information regarding LRC, DFS, and OS. The OTT was the most important prognostic factor both in the high-risk and intermediate-risk patients. Reducing the OTT to 6 weeks or less is a rather simple measure to achieve a considerable improvement of the outcome of treatment in this category of patients.

Speech outcome after surgical treatment for oral and oropharyngeal cancer: a longitudinal assessment of patients reconstructed by a microvascular flap

The aim of the study was to analyze speech outcome for patients with advanced oral/oropharyngeal cancer treated with reconstructive surgery and adjuvant radiotherapy.

Permanent unilateral hearing loss after radiotherapy for parotid gland tumors

The purpose of this retrospective study was to determine the long‐term effects of radiotherapy on hearing function in patients who underwent parotidectomy and postoperative radiotherapy for unilateral tumors of the parotid gland.

Impact of 18-fluorodeoxyglucose positron emission tomography on computed tomography defined target volumes in radiation treatment planning of esophageal cancer: reduction in geographic misses with equal inter-observer variability

Target volume definition in modern radiotherapy is based on planning computed tomography (CT). So far, 18-fluorodeoxyglucose positron emission tomography (FDG-PET) has not been included in planning modality in volume definition of esophageal cancer. This study evaluates fusion of FDG-PET and CT in patients with esophageal cancer in terms of geographic misses and inter-observer variability in volume definition. In 28 esophageal cancer patients, gross, clinical and planning tumor volumes (GTV; CTV; PTV) were defined on planning CT by three radiation oncologists. After software-based emission tomography and computed tomography (PET/CT) fusion, tumor delineations were redefined by the same radiation-oncologists. Concordance indexes (CCIs) for CT and PET/CT based GTV, CTV and PTV were calculated for each pair of observers. Incorporation of PET/CT modified tumor delineation in 17/28 subjects (61%) in cranial and/or caudal direction. Mean concordance indexes for CT-based CTV and PTV were 72 (55-86)% and 77 (61-88)%, respectively, vs. 72 (47-99)% and 76 (54-87)% for PET/CT-based CTV and PTV. Paired analyses showed no significant difference in CCI between CT and PET/CT. Combining FDG-PET and CT may improve target volume definition with less geographic misses, but without significant effects on inter-observer variability in esophageal cancer.

Improved detection of recurrent laryngeal tumor after radiotherapy using 18FDG-PET as initial method

BACKGROUND AND PURPOSE Timely detection of recurrent laryngeal tumor after radiation is an important predictive factor for curation as well as preservation of laryngeal function. Direct laryngoscopy under general anesthesia with taking of biopsies is the standard diagnostic procedure to detect recurrence when suspicion is raised. This, however, is an invasive and potentially damaging technique. Hence, a non-invasive diagnostic procedure, such as (18)FDG-PET to stratify patients for direct laryngoscopy could be useful. (18)FDG-PET is interpreted visually so that observer variation may affect clinical practice. In the present study, we therefore investigated this aspect of reproducibility. PATIENTS AND METHODS Thirty consecutive patients suspected of recurrent laryngeal carcinoma after radiotherapy underwent (18)FDG-PET and direct laryngoscopy under general anesthesia with taking of biopsies. (18)FDG-PET scans were reported by nine nuclear medicine physicians and residents, using a three-point scaling system. The reference was the absence or appearance of a local recurrence in the 12 months following (18)FDG-PET. RESULTS Eight patients had biopsy proven recurrent laryngeal carcinoma. Sensitivity of (18)FDG-PET was 88% (95% CI 53-98%) and specificity was 82% (95% CI 62-93%). The observers had a moderate to reasonable agreement (weighted kappa 0.45 (95% CI 0.20-0.69)) vs. the clinical gold standard and interobserver kappa was 0.54 (95% CI 0.40-0.69). CONCLUSION (18)FDG-PET seems to be a promising technique to detect recurrent laryngeal carcinoma after radiotherapy, and selecting patients for direct laryngoscopy. This will avoid futile invasive procedures. Interobserver agreement and variability is reasonable using this technique, but training is necessary. Studies comparing different strategies to select patients for direct laryngoscopy in case of suspected recurrence are warranted.

OC-0261: CT Image biomarkers improve the prediction of xerostomia and sticky saliva

Purpose or Objective: Current models for the prediction of xerostomia and sticky saliva after radiotherapy (RT) are based on clinical and dosimetric information. Our hypothesis is that such models can be improved by the addition of patient-specific characteristics, quantified in CT image biomarkers (IBMs). The aim of this study is to improve the performance of prediction models for patient-rated moderate-to-severe xerostomia (Xer12m) and sticky saliva (STIC12m) 12 months after radiotherapy with the addition of these IBMs obtained from CT images before the start of RT.

EP-1812: Adaptive VMAT for cT1-2aN0M0 laryngeal cancer: potential risk of target volume over dosage

ESTRO 35 2016 _____________________________________________________________________________________________________ Results: Figure 1 displays the mean differences of the dose metrics between repeated CT and CBCT, for Varian and Elekta CBCT scans. For Varian, a good agreement between the dose distributions recalculated on CBCT and repeated CT was observed when a thorax-specific HU-ED table was used. For Elekta, the dose metrics showed larger deviations with the thorax-specific HU-ED table, however, using a patientspecific HU-ED table resulted in similar accuracy as for Varian CBCT dose calculations. Differences between repeated CT and CBCT dose metrics were below 3% for both vendors.