AB 59. Re-irradiation with 3D-conformal radiotherapy in patients with lung cancer. Report in two cases
Background: There are cases of patients with Lung cancer, which have received radiation therapy in mediastinum and the tumor mass (45- 50 Gy) and after uncertain period in their life, they need re-irradiation due to recurrent tumor mass which is close to previous radiation field. 3D Conformal Radiotherapy, the last years, is used always and more, because of the minimal dangerous of radiation myelitis. Re-irradiation of patients with lung cancer and the role of 3D Conformal radiotherapy in the overall-survival and the quality of life in these patients.
Patients and methods: 68 years-old patient with lung cancer of the right upper lob, was irradiated 3 years ago, and he was refered in our department with recurrent tumor mass, close to previous radiation field. Patient has received 45 Gy, total dose, in mediastinum and the tumor mass, with anterior-posterior fields (in different department of radiation oncology). We have take mention of the fields and doses which have received the spinal cord, heart and unilateral lung. After CT simulation, determination of the clinical target volume(CTV) of the tumor mass, determination of the organ at risk (OAR), 2D-3D treatment planning, the patient was irradiated with 2.500 cGy (10 fractions with 250 cGy/ fraction) conformal RT, with linear accelerator with MLC-multilief collimator (in the recurrent tumor mass). The medical physics were used 3 radiation fields for avoidance the irradiation of spinal cord and the other organ at risk. The second patient, woman, 58 years old, with lung cancer was irradiated 2 years ago, in the mediastinum due to dyspneia from tumor mass in the mediastinum and the left middle lob. She was received 30 Gy in 10 fractions with 3 Gy/Fr. The patient was re-irradiated due to reccurence, after CT simulation and 3D Conformal treatment planning, with linear accelerator with MLC. She was received 20 Gy in the tumor mass with 20 Gy/Fr in 10 fractions. It was also done the Dose Volume histogram (DVH) from the medical physics. They have take care for the dose limitations in the organs at risk. There was also used 3 fields for radiation treatment.
Results: In the two patients which re-irradiated in the follow-up after 1, 2, 3, 4, 5, 6, 7 months there was not appearance toxicity from the organs at risk such as spinal cord, heart, unilateral lung. The respiratory function was better. There was not appearance of radiation myelitis (or Chermitte’s syndrome) sudden electric-like shocks extending down the spine with head flexion usually resolves spontaneously). Patients did not showed to have complications such as acute pericarditis, pulmonary fibrosis, radiation pneumonitis. The CT-of thorax showed decrease of the recurrent mass.
Conclusions: With 3D Conformal RT succeed in maximum therapeytical radiation dose for the re-irradiation, in the patients with recurrent mass and lung cancer, without overcame the dose limitations of the organ at risk. So, increase the overall- survival in the re-irradiated patients and improves their quality of life.
