Comparison of hyper- and hypofractionated radiation schemes with IMRT technique in small cell lung cancer: Clinical outcomes and the introduction of extended LQ and TCP models.
Radiother Oncol
; 136: 98-105, 2019 07.
Article
em En
| MEDLINE
| ID: mdl-31015136
ABSTRACT
PURPOSE:
To evaluate the outcomes of 45â¯Gy/15â¯fractions/once-daily and 45â¯Gy/30â¯fractions/twice-daily radiation schemes utilizing intensity-modulated radiation therapy (IMRT) in extensive stage small cell lung cancer (SCLC), and to build up a new radiobiological model for tumor control probability (TCP) considering multiple biological effects.METHODS:
Fifty-eight consecutive patients diagnosed with extensive stage SCLC, treated with chemotherapy and chest irradiation, were retrospectively reviewed. Thirty-seven received hyperfractionated IMRT (Hyper-IMRT, 45â¯Gy/30â¯fractions/twice-daily) and 21 received hypofractionated IMRT (Hypo-IMRT, 45â¯Gy/15â¯fractions/once-daily). Local progression-free survival (LPFS) and overall survival (OS) were calculated and compared. An extended linear-quadratic (LQ) model, LQRG, incorporating cell repair, redistribution, reoxygenation, regrowth and Gompertzian tumor growth was created based on the clinical data. The TCP model was reformulated to predict LPFS. The classical LQ and TCP models were compared with the new models. Akaike information criterion (AIC) was used to assess the quality of the models.RESULTS:
The 2-year LPFS (34.1% vs 27.9%, pâ¯=â¯0.44) and OS (76.9% vs 76.9%, pâ¯=â¯0.26) were similar between Hyper- and Hypo-IMRT patients. According to the LQRG model, the α/ß calculated was 9.2 (95% confidence interval 8.7-9.9) Gy after optimization. The average absolute and relative fitting errors for LPFS were 9.1% and 18.7% for Hyper-IMRT, and 8.8% and 16.2% for Hypo-IMRT of the new TCP model, compared with 29.1% and 62.3% for Hyper-IMRT, and 30.7% and 65.3% for Hypo-IMRT of the classical model.CONCLUSIONS:
Hypo- and Hyper-IMRT resulted in comparable local control in the chest irradiation of extensive stage SCLC. The LQRG model has better performance in predicting the TCP (or LPFS) of the two schemes.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fracionamento da Dose de Radiação
/
Radioterapia de Intensidade Modulada
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Carcinoma de Pequenas Células do Pulmão
/
Neoplasias Pulmonares
Tipo de estudo:
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article