New Study Examines How Comorbid Conditions Hinder Timely Lung Cancer Diagnosis

Comorbid conditions can postpone the diagnosis of lung cancer by occupying the time of general practitioners, thereby diminishing the likelihood of immediate cancer investigations. Additionally, they can provide a credible non-cancer rationale for specific signs and symptoms.

A group of researchers from the Brighton and Sussex Medical School in the U.K. looked to discover the effect of comorbidities on diagnostic interval for lung cancer by using electronic health record data for patients in England.

The results of the cohort study were published on Aug. 23 in the British Journal of Cancer and concluded that clinical guidelines should incorporate the impact of alternative and competing causes upon delayed lung cancer diagnosis.

The study distinguished between “competing demand” and “alternative explanation” conditions.

Imogen Rogers

“We consulted with clinicians — GPs and clinically trained cancer epidemiologists — to classify the conditions into the two groups,” explained Imogen Rogers, research fellow in health data science at the Brighton and Sussex Medical School in the UK, who led the study. “The significance is to elucidate the mechanism by which comorbidities result in diagnostic delay.”

The research team utilized data from 11,879 lung cancer patients and found that the adjusted analyses diagnostic interval was longer for patients with alternative explanation conditions, by 31 and 74 days in patients with one and 2 or less conditions compared to those with zero.

The researchers used a multivariable linear regression models for their analysis.

“As the target audience was clinicians, we wanted to choose a method that would give easily interpretable results, and this method gave the difference in days associated with the presence of comorbidities and the other factors in the model,” Rogers said. “We ran a number of different regression models —including a Cox’s regression model — and they all generated very similar conclusions about the effect of the different factors on time to diagnosis.”

Given that the presence of “alternative explanation” conditions delayed diagnosis significantly, Rogers suggests that clinical guidelines should highlight the potential for conditions such as chronic obstructive pulmonary disease o mask early symptoms of lung cancer.

“Raising awareness of this issue among primary care physicians could help to reduce diagnostic delays,” she said. “This is a retrospective analysis with no control group, so we would stop short of making specific recommendations for clinical guidelines based on this work.”

One possible area of future research, Rogers noted, would be to conduct a retrospective cohort study or a case-control study of patients with COPD/asthma who do and don’t go on to develop lung cancer.

“This could help to define particular symptoms/combinations of symptoms associated with a particularly high risk of developing lung cancer, which could be used to identify patients who might benefit most from regular screening,” she said. “In addition, this could help to avoid over-investigation of patients, which also has its associated harms.”