RESUMO
PURPOSE: To assess the benefits of magnetic resonance imaging (MRI) in the dosimetric treatment planning for prostate radiotherapy. PATIENTS AND METHODS: Ten consecutive patients have been enrolled. They were treated for a low risk prostate adenocarcinoma. A rigid superimposition was performed between MRI and scan slides obtained at time of virtual simulation, then prostate volume was delineated by four to five physicians, on TDM slides and on MRI/TDM superimposition. For each treatment plan, we assessed the impact of MRI in terms of planned treatment volume (PTV) position, individual variability of prostate delineation and doses delivered to the critical organs. The prescribed dose was 74 Gy in 37 fractions to the PTV. RESULTS: PTV delineated on TDM (V(TDM)) were 1.15 (SD 3.71) larger than volumes delineated on MRI. Prostate apex was 4.6 mm (SD 2.87) lower on TDM than on MRI. Posterior limit of the prostate was in mean 4 mm more posterior on TDM. The variability between physicians in terms of prostate delineation was lower using MRI. For apex, these variations were 6.8 mm using TDM, versus 3.3 mm using MRI. Mean rectal dose was 8 % lower with MRI, compared to delineation using TDM. CONCLUSION: Superimposition TDM/MRI improves accuracy, decreases delineation variability, and allows to spare anterior part of the rectum from irradiation. It remains unknown whether this strategy translates into clinical benefit.
Assuntos
Adenocarcinoma/patologia , Adenocarcinoma/radioterapia , Imageamento por Ressonância Magnética , Neoplasias da Próstata/patologia , Neoplasias da Próstata/radioterapia , Humanos , Masculino , Planejamento da Radioterapia Assistida por ComputadorRESUMO
Radiation therapy plays an essential role in the treatment of invasive breast cancer. However, prophylactic treatment of supra- and infraclavicular lymph nodes is not consensual, with different treatment depending on the centres and practitioners. Clinical indications for radiotherapy of the supra- and infraclavicular lymph nodes are often the subject of a consensus. Nevertheless, radiotherapy induces some toxicity. Various techniques have been developed. To date, conformal radiotherapy allows an accurate assessment of doses to target volumes and organs at risk, but at the cost of a sometime complex delineation. This article reviews the literature on radiation of supra- and infraclavicular lymph nodes, with a special focus on technical aspects in delineation and its potential toxicity.
Assuntos
Neoplasias da Mama/radioterapia , Irradiação Linfática/métodos , Clavícula , Feminino , Humanos , Irradiação Linfática/efeitos adversos , Metástase LinfáticaRESUMO
The radiotherapy of thoracic cancers exposes the heart to late radiation-induced complications. The physiopathological and clinical consequences of heart irradiation have been mostly studied in patients with Hodgkin lymphoma and breast cancer. The main cause of cardiac morbidity is radiation-induced coronaropathy with a relative risk estimated between 2 and 3 in earlier studies. Preexisting factors of cardiovascular risk, including chemotherapy, potentalize the cardiotoxicity of radiotherapy. Conformational radiotherapy, adapting the ballistics and the energy to the delineated volumes while carefully evaluating the dose-volume distribution in the organs at risk, allowed a drastic reduction in cardiac mortality. This toxicity no longer seems to be significant if the cardiac volume has received less than 30 Gy. Nevertheless, the prolonged life expectancy of cancer patients and the expanding use of new cardiotoxic anticancer drugs underline the persistent need to further reduce the dose delivered to the heart. Indeed, 1 Gy added to the mean heart dose would increase the cardiotoxic risk by 4% (IC 95%: 2-6%, P=0.0002). A strengthened collaboration between the radiation oncologist and the cardiologist aims at detecting and treating long-term complications after thoracic radiotherapy.
Assuntos
Vasos Coronários/efeitos da radiação , Coração/efeitos da radiação , Lesões por Radiação/etiologia , Radioterapia/efeitos adversos , Adolescente , Adulto , Neoplasias da Mama/radioterapia , Criança , Relação Dose-Resposta à Radiação , Feminino , Doença de Hodgkin/radioterapia , Humanos , Neoplasias Pulmonares/radioterapia , Estudos Multicêntricos como Assunto , Órgãos em Risco , Pericárdio/efeitos da radiação , Lesões por Radiação/patologia , Lesões por Radiação/fisiopatologia , Lesões por Radiação/prevenção & controle , Tolerância a Radiação , Dosagem Radioterapêutica , Estudos Retrospectivos , Risco , Fatores de TempoRESUMO
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.