Abstract
Since cigarette smoking is an important cause of lung cancer and chronic bronchitis both conditions should occur together more often in cigarette smokers than would result from chance. If they do commonly occur together then severe airways obstruction, which is often associated with chronic bronchitis, should also be often associated with lung cancer. To discover whether this were so three groups of patients were studied at the London Chest Hospital. Two hundred men and 43 women who presented with lung cancer provided information on the prevalence of defined chronic bronchitis and airways obstruction in those suffering from lung cancer. The third group consisted of 233 men presenting with defined chronic bronchitis who were kept under observation to discover how many would die from lung cancer. The results suggested that simple bronchitis and lung cancer often occur together but that obstructive bronchitis and lung cancer do not often occur together. The lack of association between lung cancer and severe airways obstruction requires an explanation.