RESUMO
This study aimed to examine the cellular and molecular long-term responses of glioblastomas to radiotherapy and hadrontherapy in order to better understand the biological effects of carbon beams in cancer treatment. Eleven human glioblastoma cell lines, displaying gradual radiosensitivity, were irradiated with photons or carbon ions. Independently of p53 or O(6)-methylguanine-DNA methyltransferase(1) status, all cell lines responded to irradiation by a G2/M phase arrest followed by the appearance of mitotic catastrophe, which was concluded by a ceramide-dependent-apoptotic cell death. Statistical analysis demonstrated that: (i) the SF2(2) and the D10(3) values for photon are correlated with that obtained in response to carbon ions; (ii) regardless of the p53, MGMT status, and radiosensitivity, the release of ceramide is associated with the induction of late apoptosis; and (iii) the appearance of polyploid cells after photon irradiation could predict the Relative Biological Efficiency(4) to carbon ions. This large collection of data should increase our knowledge in glioblastoma radiobiology in order to better understand, and to later individualize, appropriate radiotherapy treatment for patients who are good candidates.
Assuntos
Neoplasias Encefálicas/radioterapia , Glioblastoma/radioterapia , Radioterapia com Íons Pesados , Fótons , Apoptose/efeitos da radiação , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Ceramidas/metabolismo , Metilases de Modificação do DNA/genética , Metilases de Modificação do DNA/metabolismo , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos da radiação , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/patologia , Humanos , Cinética , Mitose/efeitos da radiação , Tolerância a Radiação , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
Radiation therapy has a major role in the management of infiltrative breast cancers. However, there is no consensus for the prophylactic treatment of the internal mammary chain (IMC), with strategies that show strong differences according to centers and physicians. Indications for internal mammary chain radiotherapy are debated, since this treatment significantly increases the dose delivered to the heart and leads to potential technical difficulties. Important prospective data recently suggested that internal mammary chain radiotherapy would not be necessary, even in cases of internal or central tumor locations, or in patients with positive axillary lymph nodes. Although these data warrant confirmation by two other prospective trials, there is evidence that the indications for internal mammary chain radiotherapy should be careful and that high quality techniques should be used for decreasing the dose delivered to the heart. This review of literature presents the state of art on the radiotherapy of internal mammary chain, with special focus on the indications, techniques, and potential toxicity.
