RESUMO
PURPOSE: To evaluate feasibility, disease control, survival, and toxicity after adaptive 18F-fluorodeoxyglucose (FDG) positron emisson tomography (PET) guided radiotherapy in patients with recurrent and second primary head and neck squamous cell carcinoma. METHODS: A prospective trial investigated the feasibility of adaptive intensity modulated radiotherapy (IMRT)⯱ concomitant cetuximab in 10 patients. The primary endpoint was achieving a 2-year survival free of grade >3 toxicity in ≥30% of patients. Three treatment plans based on 3 PET/CT scans were consecutively delivered in 6 weeks. The range of dose painting was 66.0-85.0â¯Gy in the dose-painted tumoral volumes in 30 fractions. RESULTS: Two-year locoregional and distant control rates were 38 and 76%, respectively. Overall and disease-free survival at 2 years was 20%. No grade 4 or 5 acute toxicity was observed in any of the patients, except for arterial mucosal hemorrhage in 1 patient. Three months after radiotherapy, grade 4 dysphagia and mucosal wound healing problems were observed in 1/7 and 1/6 of patients, respectively. Grade 5 toxicity (fatal bleeding) was seen in 2 patients, at 3.8 and 4.1 months of follow-up. Data on 2year toxicity could only be assessed in 1 of the 2 surviving patients, in whom grade 4 mucosal wound healing problems were observed; no other grade >3 toxicity was observed. In this respect, a 30% 2year survival free of grade >3 toxicity will not be achieved. CONCLUSIONS: Adaptive PET-guided reirradiation is feasible. However, due to slow accrual and treatment results that seemed inconsistent with achieving the primary endpoint, the trial was stopped early.
Assuntos
Carcinoma de Células Escamosas/radioterapia , Recidiva Local de Neoplasia/radioterapia , Neoplasias Induzidas por Radiação/radioterapia , Segunda Neoplasia Primária/radioterapia , Neoplasias Otorrinolaringológicas/radioterapia , Radioterapia Guiada por Imagem/métodos , Radioterapia de Intensidade Modulada/métodos , Adulto , Idoso , Carcinoma de Células Escamosas/mortalidade , Cetuximab/uso terapêutico , Feminino , Fluordesoxiglucose F18 , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/mortalidade , Neoplasias Induzidas por Radiação/mortalidade , Segunda Neoplasia Primária/mortalidade , Neoplasias Otorrinolaringológicas/mortalidade , Tomografia por Emissão de Pósitrons , Estudos Prospectivos , Lesões por Radiação/etiologia , Lesões por Radiação/mortalidade , Planejamento da Radioterapia Assistida por ComputadorRESUMO
PURPOSE: To formulate uncertainty-based stopping criteria for Monte Carlo (MC) calculations of intensity-modulated radiotherapy and intensity-modulated arc therapy patient dose distributions and evaluate their influence on MC simulation times and dose characteristics. METHODS AND MATERIALS: For each structure of interest, stopping criteria were formulated as follows: sigma(rel)