RESUMO
PURPOSE: Radiotherapy is essential for the treatment of breast cancer (BC). However, adverse effects may occur in healthy tissue, during treatment and even after several months. Although it is known that this clinical radiosensitivity is multifactorial, the factors involved are unknown yet. In this study, we evaluated the effect of these factors on the development of radiodermatitis in patients undergoing radiotherapy. MATERIALS AND METHODS: Demographic and lifestyle data collected during face-to-face interviews of 122 BC patients and data from clinical records were investigated. Most patients underwent conventional three-dimensional radiotherapy treatment. A total dose of 50 Gy was administered (2 Gy/day), followed by a boost in a tumor bed with a total dose of 18 Gy (2 Gy/day). Radiotoxicity was evaluated weekly using the Radiation Therapy Oncology Group classification system (range, 0 to 4, according to the severity). RESULTS: In the present study, 75.4% of patients presented acute skin toxic effects with different degrees of severity. In 25% of cases, these effects manifested at the end of the fourth week at a cumulative dose of 40 Gy. The association of grade ≥2 acute skin reactions with body mass index (BMI) and breast size and between grade 3-4 and age was positive compared with controls. However, the role of the other factors could not be confirmed. CONCLUSION: Analysis of the factors related to individual radiosensitivity suggests that age, BMI and breast size play an important role in the development of acute skin toxicity during treatment. Particular attention to patients who present these characteristics would help to control treatment effectiveness and therefore optimize their quality of life.
RESUMO
PURPOSE: Reactive oxygen species (ROS) are generated as an indirect product of radiation therapy (RT). Genetic variation in genes related to ROS metabolism may influence the level of RT-induced adverse effects. We evaluated the potential association of single nucleotide polymorphism (SNP)-related response to radiotherapy injury in breast cancer patients undergoing RT. MATERIALS AND METHODS: Eighty patients receiving conventional RT were included. Acute effects were evaluated according to the Radiation Therapy Oncology Group (RTOG) scores. DNA was extracted from blood and buccal swab samples. SNPs were genotyped for GSTP1, GSTA1, SOD2, and NOS3 genes by polymerase chain reaction-based restriction fragment length polymorphism. Univariate analysis (odds ratios [ORs] and 95% confidence interval [CI]) and principal component analysis were used for correlation of SNPs and factors related to risk of developing ≥ grade 2 acute effects. RESULTS: Sixty-five patients (81.2%) showed side effects, 32 (40%) presented moderate to severe acute skin toxicity, and 33 (41.2%) manifested minimal acute skin reactions by the end of treatment. In both univariate and multivariate analyses, nominally significant associations were found among body mass index (OR, 3.14; 95% CI, 8.5338 to 1.1274; p=0.022), breast size (OR, 5.11; 95% CI, 17.04 to 1.54; p=0.004), and grade ≥ 2 acute radiation skin toxicity. A significant association was also observed between NOS3 G894T polymorphism (OR, 9.8; 95% CI, 211.6 to 0.45; p=0.041) and grade ≥ 2 acute radiation skin toxicity in patients with neo-adjuvant chemotherapy treatment. CONCLUSION: The analysis of the factors involved in individual radiosensitivity contributed to the understanding of the mechanisms underlying this trait.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/radioterapia , Estresse Oxidativo/genética , Lesões por Radiação/genética , Tolerância a Radiação/genética , Espécies Reativas de Oxigênio/metabolismo , Adulto , Fatores Etários , Idoso , Análise do Polimorfismo de Comprimento de Fragmentos Amplificados , Neoplasias da Mama/sangue , Feminino , Genótipo , Técnicas de Genotipagem/métodos , Glutationa S-Transferase pi/genética , Glutationa Transferase/genética , Humanos , Pessoa de Meia-Idade , Terapia Neoadjuvante/efeitos adversos , Terapia Neoadjuvante/métodos , Óxido Nítrico Sintase Tipo III/genética , Razão de Chances , Polimorfismo de Fragmento de Restrição/genética , Polimorfismo de Nucleotídeo Único/genética , Estudos Prospectivos , Espécies Reativas de Oxigênio/efeitos da radiação , Fatores de Risco , Análise de Sequência de DNA , Pele/efeitos da radiação , Superóxido Dismutase/genéticaRESUMO
Antecedentes: numerosos estudios han analizado la capacidad antioxidante de los arándanos. Considerando la citotoxicidad de las radiaciones ionizantes, mediada por radicales libres, es imperativo el análisis de fitocompuestos con efecto mitigante potencial. Objetivo: evaluar las propiedades radio-protectoras de de los arándanos, en relación con el daño genético inducido por rayos X. Materiales y métodos: el diseño experimental tuvo dos etapas: primero se ejecutó ensayo in vitro con diez muestras de sangre periférica de mujeres jóvenes no fumadoras. Cada muestra fue analizada mediante Ensayo Cometa en el siguiente grupo de tratamientos: control negativo, tratamiento con arándanos (0,232 mG/mL), irradiación con 4 Gy y tratamiento simultáneo arándanos/irradiación. Se contabilizaron 800 células/individuo, 200 por tratamiento, considerando su repetición. Posteriormente, se realizó ensayo in vivo con sangre periférica de dos mujeres, de condiciones similares a las anteriores, sometidas al consumo de extracto seco de arándanos durante 15 días consecutivos. El muestreo se realizó antes y después del tratamiento y se implementó el Cometa analizando 800 células/individuo, correspondientes al control negativo e irradiación con 4 Gy. Resultados: en ambas etapas, el tratamiento con arándanos demostró una reducción significativa (p<0,01) del daño genómico referido a las muestras irradiadas. Conclusiones: la suplementación dietaria con arándanos podría disminuir los efectos secundarios de la radioterapia, optimizando la calidad de vida del paciente oncológico.
Introduction: Numerous studies have analyzed the antioxidant capacity of blueberries. Considering the ionizing radiation cytotoxicity mediated by free radicals is imperative phytocompounds analysis with potential mitigating effect. Objective: To evaluate radio-protective properties of this fruit in relation to genetic damage induced by x-rays. Materials and methods: Experimental design had two stages. First an in vitro assay using 10 samples of peripheral blood of young and nonsmokers female. Each sample was analyzed by comet assay in the next set of treatments: negative control, treatment with blueberries (0,232 mG / mL), irradiation 4Gy and simultaneous blueberry/ irradiation treatment. Were counted 800 cells/individual, 200 per treatment, considering its repetition. Subsequently, an in vivo assay with peripheral blood of two women, of similar conditions and subject to the consumption of dried extract of blueberries for 15 consecutive days was performed. Sampling was performed before and after treatment and Comet was implemented by analyzing 800 cells / individual, corresponding to the negative control and irradiation with 4 Gy. Results: In both stages, treatment with blueberries showed a significant reduction (p <0.01) of genomic damage relative to irradiated samples. Conclusions: Dietary supplementation with blueberries may decrease the side effects of radiation therapy, optimizing the quality of life of cancer patients.