Validation of 3D documentation of palatal soft tissue shape, color, and irregularity with intraoral scanning.

OBJECTIVES: The purpose of this study was to assess the feasibility of 3D intraoral scanning for documentation of palatal soft tissue by evaluating the accuracy of shape, color, and curvature. MATERIALS AND METHODS: Intraoral scans of ten participants' upper dentition and palate were acquired with the TRIOS® 3D intraoral scanner by two observers. Conventional impressions were taken and digitized as a gold standard. The resulting surface models were aligned using an Iterative Closest Point approach. The absolute distance measurements between the intraoral models and the digitized impression were used to quantify the trueness and precision of intraoral scanning. The mean color of the palatal soft tissue was extracted in HSV (hue, saturation, value) format to establish the color precision. Finally, the mean curvature of the surface models was calculated and used for surface irregularity. RESULTS: Mean average distance error between the conventional impression models and the intraoral models was 0.02 ± 0.07 mm (p = 0.30). Mean interobserver color difference was - 0.08 ± 1.49° (p = 0.864), 0.28 ± 0.78% (p = 0.286), and 0.30 ± 1.14% (p = 0.426) for respectively hue, saturation, and value. The interobserver differences for overall and maximum surface irregularity were 0.01 ± 0.03 and 0.00 ± 0.05 mm. CONCLUSIONS: This study supports the hypothesis that the intraoral scan can perform a 3D documentation of palatal soft tissue in terms of shape, color, and curvature. CLINICAL RELEVANCE: An intraoral scanner can be an objective tool, adjunctive to the clinical examination of the palatal tissue.

Oxygen-modifying treatment with ARCON reduces the prognostic significance of hemoglobin in squamous cell carcinoma of the head and neck.

PURPOSE: To evaluate the prognostic significance of hemoglobin (Hb) levels measured before and during treatment with accelerated radiotherapy with carbogen and nicotinamide (ARCON). METHODS AND MATERIALS: Two hundred fifteen patients with locally advanced tumors of the head and neck were included in a phase II trial of ARCON. This treatment regimen combines accelerated radiotherapy for reduction of repopulation with carbogen breathing and nicotinamide to reduce hypoxia. In these patients, Hb levels were measured before, during, and after radiotherapy. RESULTS: Preirradiation and postirradiation Hb levels were available for 206 and 195 patients respectively. Hb levels below normal were most frequently seen among patients with T4 (p < 0.001) and N2 (p < 0.01) disease. Patients with a larynx tumor had significantly higher Hb levels (p < 0.01) than other tumor sites. During radiotherapy, 69 patients experienced a decrease in Hb level. In a multivariate analysis there was no prognostic impact of Hb level on locoregional control, disease-free survival, and overall survival. Primary tumor site was independently prognostic for locoregional control (p = 0.018), and gender was the only prognostic factor for disease-free and overall survival (p < 0.05). High locoregional control rates were obtained for tumors of the larynx (77%) and oropharynx (72%). CONCLUSION: Hemoglobin level was not found to be of prognostic significance for outcome in patients with squamous cell carcinoma of the head and neck after oxygen-modifying treatment with ARCON.

ARCON: experience in 215 patients with advanced head-and-neck cancer.

PURPOSE: "ARCON" combines accelerated radiotherapy to counteract tumor repopulation with carbogen breathing and nicotinamide to reduce chronic and acute hypoxia. The aim of this Phase II study was to assess the feasibility, toxicity, and potential effectiveness of ARCON for advanced head-and-neck cancer. METHODS AND MATERIALS: The study included 215 patients with head-and-neck carcinoma distributed as follows: larynx, n = 100; hypopharynx, n = 50; oropharynx, n = 52; oral cavity, n = 13; Stage II, n = 8, Stage III, n = 71, and Stage IV, n = 136. Accelerated radiotherapy was given to a total dose of 64-68 Gy in 2-Gy fractions within 36-38 days. This was combined with carbogen breathing during irradiation and administration of nicotinamide (60-80 mg/kg) 1-1.5 h before irradiation. RESULTS: There was full compliance with carbogen breathing in 88% of the patients. A nicotinamide dose of 80 mg/kg produced severe nausea and vomiting, necessitating discontinuation of the drug, in 31% of the patients. Adjustment of the dose to 60 mg/kg and antiemesis prophylaxis reduced the discontinuation rate to 10%. Confluent mucositis was observed in 91% of the patients with a median duration of 6 weeks. Grade 4 late complications occurred in 5% of the patients. The actuarial 3-year local control rates were 80% for larynx, 69% for hypopharynx, 88% for oropharynx, and 37% for oral cavity tumors. For T3-4 tumors, the local control rates were 80% for larynx, 60% for hypopharynx, 87% for oropharynx, and 29% for oral cavity. Regional control rates were 100% for N0, 93% for N1, and 74% for N2 disease. CONCLUSION: ARCON yields high local and regional control rates in advanced head-and-neck carcinomas, and compliance is satisfactory and morbidity acceptable. The local control rate of 80% for T3 and T4 larynx carcinomas offers excellent possibilities for organ preservation.