ACUTE CHANGES IN PEAK EXPIRATORY FLOW-RATE FOLLOWING PALLIATIVE RADIOTHERAPY FOR BRONCHIAL-CARCINOMA

Purpose: Changes in respiratory function occurring in the months and y ears following radiotherapy have been well documented. The changes tha t occur in the hours after treatment are less clear, we report a study that recorded peak expiratory flow rate (PEFR) in the 72 h following radiotherapy to the mediastinum and large airways. Methods: Fifty-six patients with carcinoma affecting the major bronchii were recruited; 3 9 were male, with a median age of 66 years; 49 had histologically conf irmed lung cancer. The median baseline PEFR was 300 1/s (range: 120-60 0). Patients were asked to record home PEFR readings in the 72 h that followed the first fraction of radiotherapy. Doses ranges from an 8-Gy single fraction to 60 Gy in 30 fractions. Results: Forty-nine patient s recorded a fall in PEFR (3%-60% of the baseline value) in the 24 h a fter radiotherapy, the mean for all 56 patients was a fall of 20.3% (9 5% confidence interval -15.8% to -24.8%). These lowest values occurred a median time of 6 h after treatment (range: 2-24 h). By 72 h the mea n PEFR had returned to the baseline. Tumour site (central or lobar bro nchus) and fraction size (<3 GY or >3 Gy) had no significant effect on the fall in PEFR (Mann-Whitney U-test P = 0.15 and P = 0.06, respecti vely). Conclusion: We conclude that a fail in PEFR can occur after rad iotherapy treatment to the mediastinum. This is of concern in patients being treated for bronchial carcinoma whose respiratory function may already be compromised. (C) 1997 Elsevier Science B.V.