[Incidence of pulmonary scintigraphic changes in women irradiated for breast cancer].
OBJECTIVE: To determine the incidence of respiratory function changes on quantified ventilation-perfusion scintigraphy produced by breast cancer radiation therapy and its correlation with irradiated lung volume. MATERIAL AND METHODS: Prospective study on 43 patients with breast cancer who received adjuvant radiotherapy. Quantified ventilation-perfusion scintigraphy was carried out before and after radiotherapy (3 and 9 months). The differences of ventilation and perfusion were calculated subtracting the irradiated lung values from the contralateral lung values, and their correlations with the irradiated lung volume were analyzed. RESULTS: The scintigraphic parameter means of the irradiated lung were significantly lower than those of the contralateral lung, after radiotherapy. The incidence of patients with a total perfusion and ventilation decrease over 10 % was 21 %, except for the three-month ventilation, which was 23 %. The total ventilation difference was significantly correlated with the lung volume, presenting decreases over 10 % for volumes of 100 cm3 or more. All patients remained asymptomatic. CONCLUSIONS: The pulmonary scintigraphy changes derived from the breast cancer radiotherapy produced no clinical symptomatology. Regarding scintigraphy, ventilation decreases when the irradiated lung volume increases, so a follow-up of these patients' pulmonary function should be performed when the lung volume irradiation cannot be lower than 100 cm3.