[Incidence of pulmonary scintigraphic changes in women irradiated for breast cancer]

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.

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.

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.

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.