López, EscarlataGuerrero, RosarioNúñez, Maria IMoral, Rosario delVillalobos, MercedesMartínez-Galán, JoaquinaValenzuela, Maria TMuñoz-Gámez, José AOliver, Francisco JMartín-Oliva, DavidRuiz de Almodóvar, José Mariano2012-11-212012-11-212005-07-01López E, Guerrero R, Núñez MI, Moral R , Villalobos M , Martínez-Galán J et al. Early and late skin reactions to radiotherapy for breast cancer and their correlation with radiation-induced DNA damage in lymphocytes. Breast Cancer Res. 2005;7(5):R690-8. Epub 2005 Jul 1.1465-5411http://hdl.handle.net/10668/636Journal Article; Research Support, Non-U.S. Gov't;INTRODUCTION Radiotherapy outcomes might be further improved by a greater understanding of the individual variations in normal tissue reactions that determine tolerance. Most published studies on radiation toxicity have been performed retrospectively. Our prospective study was launched in 1996 to measure the in vitro radiosensitivity of peripheral blood lymphocytes before treatment with radical radiotherapy in patients with breast cancer, and to assess the early and the late radiation skin side effects in the same group of patients. We prospectively recruited consecutive breast cancer patients receiving radiation therapy after breast surgery. To evaluate whether early and late side effects of radiotherapy can be predicted by the assay, a study was conducted of the association between the results of in vitro radiosensitivity tests and acute and late adverse radiation effects. METHODS Intrinsic molecular radiosensitivity was measured by using an initial radiation-induced DNA damage assay on lymphocytes obtained from breast cancer patients before radiotherapy. Acute reactions were assessed in 108 of these patients on the last treatment day. Late morbidity was assessed after 7 years of follow-up in some of these patients. The Radiation Therapy Oncology Group (RTOG) morbidity score system was used for both assessments. RESULTS Radiosensitivity values obtained using the in vitro test showed no relation with the acute or late adverse skin reactions observed. There was no evidence of a relation between acute and late normal tissue reactions assessed in the same patients. A positive relation was found between the treatment volume and both early and late side effects. CONCLUSION After radiation treatment, a number of cells containing major changes can have a long survival and disappear very slowly, becoming a chronic focus of immunological system stimulation. This stimulation can produce, in a stochastic manner, late radiation-related adverse effects of varying severity. Further research is warranted to identify the major determinants of normal tissue radiation response to make it possible to individualize treatments and improve the outcome of radiotherapy in cancer patients.enBraquiterapiaNeoplasias de la MamaRadioisótopos de CobaltoDaño del ADNDNA, NeoplasmFraccionamiento de la DosisFemeninoEstudios de SeguimientoRadioisótopos de IridioLinfocitosAceleradores de PartículasRadioisótopos de IridioFactores de TiempoMedical Subject Headings::Diseases::Neoplasms::Neoplasms by Site::Breast NeoplasmsMedical Subject Headings::Chemicals and Drugs::Inorganic Chemicals::Isotopes::Cobalt IsotopesMedical Subject Headings::Phenomena and Processes::Genetic Phenomena::Genetic Processes::DNA DamageMedical Subject Headings::Chemicals and Drugs::Nucleic Acids, Nucleotides, and Nucleosides::Nucleic Acids::DNA::DNA, NeoplasmMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Therapeutics::Radiotherapy::Radiotherapy Dosage::Dose FractionationMedical Subject Headings::Check Tags::FemaleMedical Subject Headings::Health Care::Health Care Quality, Access, and Evaluation::Quality of Health Care::Health Care Evaluation Mechanisms::Epidemiologic Study Characteristics as Topic::Epidemiologic Studies::Cohort Studies::Follow-Up StudiesMedical Subject Headings::Organisms::Eukaryota::Animals::Chordata::Vertebrates::Mammals::Primates::Haplorhini::Catarrhini::Hominidae::HumansMedical Subject Headings::Chemicals and Drugs::Inorganic Chemicals::Isotopes::Radioisotopes::Iridium RadioisotopesMedical Subject Headings::Anatomy::Cells::Blood Cells::Leukocytes::Leukocytes, Mononuclear::LymphocytesMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Equipment and Supplies::Radiation Equipment and Supplies::Particle AcceleratorsMedical Subject Headings::Phenomena and Processes::Physical Phenomena::Time::Time FactorsMedical Subject Headings::Analytical, Diagnostic and Therapeutic Techniques and Equipment::Therapeutics::Radiotherapy::Brachytherapyresearch article16168114open access10.1186/bcr1277PMC1242135