Dosimetric predictors of acute hematologic toxicity during concurrent intensity-modulated radiotherapy and chemotherapy for anal cancer.
Clin Transl Oncol
; 19(1): 67-75, 2017 Jan.
Article
em En
| MEDLINE
| ID: mdl-27037814
PURPOSE: This study aimed at investigating whether the irradiated volume of pelvic bone marrow (PBM) and specific subsites may predict the occurrence of acute hematologic toxicity (HT) in anal cancer patients undergoing concurrent chemo-radiation. METHODS: 50 patients, submitted to IMRT and concurrent chemotherapy, were analyzed. Several bony structures were defined on planning-CT: PBM and lumbar-sacral (LSBM), lower pelvis (LPBM) and iliac (IBM) bone marrow. On dose-volume histograms, dosimetric parameters were taken. Endpoints included white blood-cell-count (WBC), absolute-neutrophil-count (ANC), hemoglobin (Hb) and platelet nadirs and acute hematologic toxicity (HT) according to RTOG scoring scale. Generalized linear modeling was used to find correlations between dosimetric variables and blood cell nadirs, while logistic regression analysis was used to test correlation with ≥G3 HT. Receiver Operating Characteristic (ROC) curve analysis was used to evaluate the optimal cut-off points for predictive dosimetric variables with the Youden method. RESULTS: Maximum detected acute HT comprised 38 % of ≥G3 leukopenia and 32 % of ≥G3 neutropenia. Grade 2 anemia was observed in 4 % of patients and ≥G3 thrombocytopenia in 10 %. On multivariate analysis a higher PBM-V 20 was associated with lower WBC nadir. Increased LSBM-V 40 was correlated with a higher likelihood to develop ≥G3 HT. A cut-off point at 41 % for LSBM-V 40 was found. Patients with LSBM-V 40 ≥41 % were more likely to develop ≥G3 HT (55.3 vs. 32.4 %; p < 0.01). CONCLUSIONS: Increased low-dose to pelvic bony structures significantly predicted for WBC decrease. Medium-high dose to specific osseous subsites was associated with a higher probability of HT. LSBM-V 40 was a strong predictor of ≥G3 HT. A threshold at 41 % for LSBM-V 40 could be used to limit HT.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias do Ânus
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Carcinoma de Células Escamosas
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Protocolos de Quimioterapia Combinada Antineoplásica
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Radioterapia de Intensidade Modulada
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Quimiorradioterapia
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Doenças Hematológicas
Tipo de estudo:
Etiology_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Adult
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Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Clin Transl Oncol
Ano de publicação:
2017
Tipo de documento:
Article
País de afiliação:
Itália
País de publicação:
Itália