RESUMO
PURPOSE: To identify clinical risk factors and dose-volume thresholds for treatment-related pneumonitis (TRP) in patients with non-small cell lung cancer (NSCLC). METHODS AND MATERIALS: Data were retrospectively collected from patients with inoperable NSCLC treated with radiotherapy with or without chemotherapy. TRP was graded according to Common Terminology Criteria for Adverse Events, version 3.0, with time to grade > or = 3 TRP calculated from start of radiotherapy. Clinical factors and dose-volume parameters were analyzed for their association with risk of TRP. RESULTS: Data from 576 patients (75% with stage III NSCLC) were included in this study. The Kaplan-Meier estimate of the incidence of grade > or = 3 TRP at 12 months was 22%. An analysis of dose-volume parameters identified a threshold dose-volume histogram (DVH) curve defined by V(20) < or = 25%, V(25) < or = 20%, V(35) < or = 15%, and V(50) < or = 10%. Patients with lung DVHs satisfying these constraints had only 2% incidence of grade > or = 3 TRP. Smoking status was the only clinical factor that affected the risk of TRP independent of dosimetric factors. CONCLUSIONS: The risk of TRP varied significantly, depending on radiation dose-volume parameters and patient smoking status. Further studies are needed to identify biological basis of smoking effect and methods to reduce the incidence of TRP.
Assuntos
Carcinoma Pulmonar de Células não Pequenas/radioterapia , Neoplasias Pulmonares/radioterapia , Pneumonite por Radiação/etiologia , Fumar/efeitos adversos , Antineoplásicos/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/patologia , Comorbidade , Relação Dose-Resposta à Radiação , Feminino , Humanos , Incidência , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Pneumonite por Radiação/epidemiologia , Dosagem Radioterapêutica , Estudos Retrospectivos , Fatores de Risco , Resultado do TratamentoRESUMO
This study uses numerical solutions of a bio-heat transfer equation to investigate the relationship between skin surface temperature distributions and internal heat sources under various physiological and environmental conditions. It is found that although a surface temperature distribution depends on all heat source parameters, the properly normalized distribution is primarily affected only by the depth of the heat source. This study provides a physical basis for determining the depth and type of an internal heat source from a thermogram acquired in various environmental conditions and an understanding of the basic relationship between skin surface temperature distributions and internal heat sources.