Effects of ongoing smoking on the development of radiation-induced pneumonitis in breast cancer and oesophagus cancer patients

Purpose: To investigate the influence of smoking on the development of radi ation-induced pneumonitis in patients treated for breast and oesophagus can cer. Materials and methods: This is a retrospective study on 405 females diagnos ed with primary unilateral breast cancer stages 1 and 2 and 201 oesophagus carcinoma patients. The possibilities in Sweden to obtain detailed informat ion from different medical records were used to collect data on smoking hab its, radiation treatment and spontaneously reported pneumonitis. Radiation- induced pneumonitis was defined as a combination of roentgenographic infilt rate in the lung field involving an irradiated area on the chest X-ray and clinical symptoms such as non-productive cough and dyspnoea. Results: Six breast cancer patients had spontaneously reported pneumonitis. Five of them were non-smokers (P = 0.182) and the other was a former smoke r. Eight of the oesophagus cancer patients had spontaneously reported radia tion-induced clinical pneumonitis and they were all non-smokers (P = 0.022) , except one, who was a pipe smoker. None of the patients who were cigarett e smokers were recorded as developing clinical pneumonitis after irradiatio n. Conclusion: These data could support the previous clinical observations and experimental studies that smoking depresses the frequency of radiation-ind uced pneumonitis. The present study as well as earlier observations could j ustify further studies concerning the possibility of an interaction of smok ing with cancer treatment, both from the view of therapeutic failures and r educed adverse effects. (C) 1998 Elsevier Science Ireland Ltd. All rights r eserved.