The observational clinical registry (cohort design) of the European Reference Network on Rare Adult Solid Cancers: The protocol for the rare head and neck cancers.

INTRODUCTION: Care for head and neck cancers is complex in particular for the rare ones. Knowledge is limited and histological heterogeneity adds complexity to the rarity. There is a wide consensus that to support clinical research on rare cancer, clinical registries should be developed within networks specializing in rare cancers. In the EU, a unique opportunity is provided by the European Reference Networks (ERN). The ERN EURACAN is dedicated to rare adults solid cancers, here we present the protocol of the EURACAN registry on rare head and neck cancers (ClinicalTrials.gov Identifier: NCT05483374). STUDY DESIGN: Registry-based cohort study including only people with rare head and neck cancers. OBJECTIVES: to help describe the natural history of rare head and neck cancers;to evaluate factors that influence prognosis;to assess treatment effectiveness;to measure indicators of quality of care. METHODS: Settings and participants It is an hospital based registry established in hospitals with expertise in head and neck cancers. Only adult patients with epithelial tumours of nasopharynx; nasal cavity and paranasal sinuses; salivary gland cancer in large and small salivary glands; and middle ear will be included in the registry. This registry won't select a sample of patients. Each patient in the facility who meets the above mentioned inclusion criteria will be followed prospectively and longitudinally with follow-up at cancer progression and / or cancer relapse or patient death. It is a secondary use of data which will be collected from the clinical records. The data collected for the registry will not entail further examinations or admissions to the facility and/or additional appointments to those normally provided for the patient follow-up. Variables Data will be collected on patient characteristics (eg. patient demographics, lifestyle, medical history, health status); exposure data (eg. disease, procedures, treatments of interest) and outcomes (e.g. survival, progression, progression-free survival, etc.). In addition, data on potential confounders (e.g. comorbidity; functional status etc.) will be also collected. Statistical methods The data analyses will include descriptive statistics showing patterns of patients' and cancers' variables and indicators describing the quality of care. Multivariable Cox's proportional hazards model and Hazard ratios (HR) for all-cause or cause specific mortality will be used to determine independent predictors of overall survival, recurrence etc. Variables to include in the multivariable regression model will be selected based on the results of univariable analysis. The role of confounding or effect modifiers will be evaluated using stratified analysis or sensitivity analysis. To assess treatment effectiveness, multivariable models with propensity score adjustment and progression-free survival will be performed. Adequate statistical (eg. marginal structural model) methods will be used if time-varying treatments/confounders and confounding by indication (selective prescribing) will be present. RESULTS: The registry initiated recruiting in May 2022. The estimated completion date is December 2030 upon agreement on the achievement of all the registry objectives. As of October 2022, the registry is recruiting. There will be a risk of limited representativeness due to the hospital-based nature of the registry and to the fact that hospital contributing to the registry are expert centres for these rare cancers. Clinical Follow-up could also be an issue but active search of the life status of the patients will be guaranteed.

Application and accuracy of ultrasound-guided resections of tongue cancer.

OBJECTIVES: Surgical removal of squamous cell carcinoma of the tongue (SCCT) with tumour-free margin status (≥5 mm) is essential for loco-regional control. Inadequate margins (<5 mm) often indicate adjuvant treatment, which results in increased morbidity. Ultrasound (US)-guided SCCT resection may be a useful technique to achieve more adequate resection margins compared to conventional surgery. This study evaluates the application and accuracy of this technique. METHODS: Forty patients with SCCT were included in a consecutive US cohort. During surgery, the surgeon aimed for a 10-mm echographic resection margin, while the tumour border and resection plane were captured in one image. Ex-vivo US measurements of the resection specimen determined whether there was a need for an immediate re-resection. The margin status and the administration of adjuvant treatment were compared those of with a consecutive cohort of 96 tongue cancer patients who had undergone conventional surgery. A receiver operating characteristic analysis was done to assess the optimal margin of ex-vivo US measurements to detect histopathologically inadequate margins. RESULTS: In the US cohort, the frequency of free margin status was higher than in the conventional cohort (55% vs. 16%, p < 0.001), and the frequency of positive margins status (<1 mm) was lower (5% vs. 15%, respectively, p < 0.001). Adjuvant radiotherapy was halved (10% vs. 21%), and the need for re-resection was comparable (10% vs. 9%). A cut-off value of 8 mm for ex-vivo measurements prevented histopathologically inadequate margins in 76%. CONCLUSION: US-guided SCCT resections improve margin status and reduce the frequency of adjuvant radiotherapy.

Hyperbaric oxygen treatment of mandibular osteoradionecrosis: Combined data from the two randomized clinical trials DAHANCA-21 and NWHHT2009-1.

PURPOSE: Osteoradionecrosis (ORN) of the mandible is a serious complication of head and neck radiotherapy. This study aims to investigate the effect of hyperbaric oxygen (HBO) treatment on ORN in two randomized, controlled multicentre trials. METHODS AND MATERIALS: Patients with ORN with indication for surgical treatment were randomised to either group 1: surgical removal of necrotic mandibular bone supplemented by 30 pre- and 10 postoperative HBO exposures at 243 kPa for 90 min each, or group 2: surgical removal of necrotic bone only. Primary outcome was healing of ORN one year after surgery evaluated by a clinically adjusted version of the Common Toxicity Criteria of Adverse Events (CTCAE) v 3.0. Secondary outcomes included xerostomia, unstimulated and stimulated whole salivation rates, trismus, dysphagia, pain, Activities of Daily Living (ADL) and quality of life according to EORTC. Data were combined from two separate trials. Ninety-seven were enrolled and 65 were eligible for the intent-to-treat analysis. The 33% drop-out was equally distributed between groups. RESULTS: In group 1, 70% (21/30) healed compared to 51% (18/35) in group 2. HBO was associated with an increased chance of healing independent of baseline ORN grade or smoking status as well as improved xerostomia, unstimulated whole salivary flow rate, and dysphagia. Due to insufficient recruitment, none of the endpoints reached a statistically significant difference between groups. ADL data could only be obtained from 50 patients. CONCLUSION: Hyperbaric oxygen did not significantly improve the healing outcome of osteoradionecrosis after surgical removal of necrotic bone as compared to standard care (70% vs. 51%). This effect is not statistically significant due to the fact that the study was underpowered and is therefore prone to type II error.

Removal of an oral squamous cell carcinoma including parts of osseointegrated implants in the marginal mandibulectomy. A case report.

PURPOSE: The incidence of oral squamous cell carcinomas (OSCC) arising around dental implants will increase because of the rising popularity of dental implants. In this case, a novel surgical treatment of an OSCC in the vicinity of endosseous implants is reported. MATERIALS AND METHODS: In a 69-year-old woman, a recurrent OSCC (cT2N0M0) developed in the floor of the mouth extending to the attached keratinized peri-implant mucosa of both interforaminal-placed dental implants. Radiographically, no bone invasion could be observed. RESULTS: To radically remove the tumor, a marginal mandibulectomy was performed including the cranial parts of both dental implants by cutting them into two parts. Three years after tumor resection and one year after reimplantation, the patient is disease free and has a good oral function. CONCLUSIONS: In case of an OSCC, traditional bone and soft margins for oncologic safety are 1.0 cm. If a dental implant is present within this safety zone, on condition, there is no massive bone invasion, and the original mandible has sufficient vertical height; a marginal mandibulectomy including part of the implants can be considered.