Predictive values of lung cancer alarm symptoms in the general population: a nationwide cohort study

Lisa M. S. Sætre,Dorte E. Jarbøl,Peter F. Haastrup,Kirubakaran Balasubramaniam,Jens Søndergaard,Sanne Rasmussen

doi:10.1038/s41533-020-0173-3

Lisa M. S. Sætre, Dorte E. Jarbøl + Show 4 more

Open Access

https://doi.org/10.1038/s41533-020-0173-3

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Abstract

We aimed to firstly determine the 1-year predictive values of lung cancer alarm symptoms in the general population and to analyse the proportion of alarm symptoms reported prior to diagnosis, and secondly analyse how smoking status and reported contact with general practitioners (GPs) regarding lung cancer alarm symptoms influence the predictive values. The study was a nationwide prospective cohort study of 69,060 individuals aged ≥40 years, randomly selected from the Danish population. Using information gathered in a survey regarding symptoms, lifestyle and healthcare-seeking together with registry information on lung cancer diagnoses in the subsequent year, we calculated the predictive values and likelihood ratios of symptoms that might be indicative of lung cancer. Furthermore, we analysed how smoking status and reported contact with GPs regarding the alarm symptoms affected the predictive values. We found that less than half of the patients had reported an alarm symptom six months prior to lung cancer diagnosis. The positive predictive values of the symptoms were generally very low, even for patients reporting GP contact regarding an alarm symptom. The highest predictive values were found for dyspnoea, hoarseness, loss of appetite and for current heavy smokers. The negative predictive values were high, all close to 100%. Given the low positive predictive values, our findings emphasise that diagnostic strategies should not focus on single, specific alarm symptoms, but should perhaps focus on different clusters of symptoms. For patients not experiencing alarm symptoms, the risk of overlooking lung cancer is very low.

Highlights

Many countries have implemented referral guidelines for patients with respiratory alarm symptoms in order to expedite diagnosis of lung cancer and reduce the diagnostic interval, increasing survival rates[1]
We analysed the predictive values and likelihood ratios of specific and nonspecific alarm symptoms of lung cancer reported by a large sample of the Danish general population ≥40 years
Respondents experiencing loss of appetite or dyspnoea or hoarseness for more than 4 weeks had the highest risk of subsequent lung cancer diagnosis

Summary

Introduction

Many countries have implemented referral guidelines for patients with respiratory alarm symptoms in order to expedite diagnosis of lung cancer and reduce the diagnostic interval, increasing survival rates[1]. Qualitative studies have demonstrated that patients with lung cancer often experience symptoms months before diagnosis, but do not interpret such symptoms as serious enough to warrant seeking health care[2]. Many health campaigns have been conducted with the aim of increasing public awareness of these alarm symptoms as indicative of cancer in hopes of reducing the interval before lung cancer diagnosis[4,5]. Despite awareness that smoking is an important risk factor for lung cancer, smokers are less likely to seek medical attention when experiencing respiratory alarm symptoms[6]

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