People who suffer from asthma, particularly women, may have an increased risk of developing lung cancer. Over a period of 30 years, researchers studied almost 100,000 patients who had been hospitalised and diagnosed with asthma. None of the patients showed any signs of cancer at their initial assessment. Their health was monitored from the second year after asthma diagnosis until the last day of the three-decade study.
At the study's conclusion, the researchers found that lung cancer affected asthmatics more frequently than the general population. They also found that the risk of developing lung cancer was higher for asthmatic women than for men. The reasons for the link between asthma and lung cancer, however, remain unclear.
Dr Paolo Boffetta, from the Unit of Environmental Cancer Epidemiology at the IARC in Lyon, France, said, "We do not really know if asthma as such causes the increased risk. "There could be one mechanism causing both asthma and cancer, for example chronic inflammation leading to an excess of free radicals."
Dr Paola also said there could be external environmental factors that play a role in the activation and progression of both asthma and lung cancer, particularly tobacco smoking. In conclusion, the researchers say their study confirms a link between asthma and lung cancer, and contradicts previous research by demonstrating that asthmatic women may have a higher, rather than lower, risk of developing lung cancer.