Predictive values of lung cancer alarm symptoms in the general population: a nationwide cohort study
Lung cancer is one of the most common worldwide, however, many patients are diagnosed at advanced stages, resulting in poor survival rates. Studies have shown that patients with lung cancer often experience symptoms prior to diagnosis but do not perceive such symptoms as serious enough to warrant seeking health care. More so, literature examining the predictive values of specific and nonspecific symptoms of lung cancer is lacking. Thus, this study aimed to determine the 1-year predictive values of lung cancer alarm symptoms and to analyse the proportion of alarm symptoms reported prior to diagnosis. Secondary analyses explored how smoking status and contact with general practitioners (GP) regarding lung cancer alarm symptoms influence predictive values. The study found that less than half of patients reported an alarm symptom prior to lung cancer diagnosis. Furthermore, even among patients in contact with GPs regarding an alarm symptom, the positive predictive value of the symptoms were generally very low. The highest predictive values were found for dyspnoea (shortness of breath), hoarseness, loss of appetite and for current heavy smokers. In contrast, the negative predictive values were all close to 100%. These findings of low positive predictive values emphasize that diagnostic strategies should focus on clusters of symptoms, rather than single specific alarm symptoms.
Local work on implementing pathways for early cancer diagnosis complements this study. Developed by the Cancer Council Victoria, I-PACED (Implementing Pathways for Cancer Early Diagnosis) provides resources for GPs with information on prevention, early detection, initial investigation and referral pathways for cancer diagnosis. Specifically, the lung cancer resource provides a lung cancer assessment tool, which includes positive predictive values for both smokers and non-smokers.