Toxicity associated to radiotherapy treatment in lung cancer patients.

Radiation therapy in combination with other treatments, such as chemotherapy, increases loco-regional control and survival in patients with lung cancer. Nevertheless, the subsequent toxicity of this treatment occurs in up to 37% of the irradiated patients. Some factors related to the patient, including performance status, pulmonary function tests (FEV1, DCLO), tumour site, as well as treatment-related factors such as radiation dose, fractionation and addition of chemotherapy, can be related to the risk of pulmonary toxicity. With the advent of tridimensional conformal radiotherapy (3DCRT), dose-volume histograms can be generated to assess the dose received by the organs at risk. Volume dose (Vdose), mean lung dose (MLD) and normal tissue complication probability (NTCP) are the dosimetric parameters most frequently used. The possible relationship between these parameters and clinical and anatomical factors has to be considered. Steroid treatment should be started soon in case of pneumonitis to avoid the development of late pulmonary fibrosis. Finally, some pharmacological agents to prevent radiation-related pneumonitis are under investigation.