Study links reflux with risk of lung cancer

A recent study has linked gastro-oesophageal reflux disease (GERD/GORD) with an increased risk of lung cancer.

Among all newly diagnosed cancer cases, lung cancer accounts for 11.4 percent, making it the second most common cancer globally. Additionally, it is responsible for 18.0 percent of all cancer-related deaths worldwide.

Multiple observational studies have suggested a connection between reflux and cancer. But they have been limited by small study size, as well as a lack of detailed information on confounders (factors that confuse the relationship between the study subject and the outcome), such as smoking, related disorders, duration of GERD and treatment history.

Researchers from the Zunyi Medical University in China have now examined the causal relationship between GERD and lung cancer in thousands of patients.

In order to investigate the potential causal relationship between gastroesophageal reflux disease (GERD) and cancer risk, researchers used a method called Mendelian randomisation (MR) analysis, which involved combining data from published genome-wide association studies.

MR analysis

MR analysis is a technique that uses genetic variants associated with the exposure of interest (in this case, GERD) as instrumental variables to assess the causal relationship between the exposure and outcome (cancer).

By using MR analysis, the researchers could account for potential confounding factors, such a smoking or related disorders, and more accurately determine whether the association between GERD and lung cancer risk was indeed causal.

The analysis suggested there is a genetic link between GERD susceptibility and lung cancer. Specifically, subgroup MR analyses also indicated that GERD was related with the increased risks of squamous cell lung carcinomas (LUSC) and lung adenocarcinomas (LUAD).

According to researchers, as the first large-scale MR investigation to examine the link between GERD and lung cancer, it is less susceptible to bias and inverse causation. They say this could help better understand the GERD patients’ possible risk factors for this cancer.

With early diagnosis and early treatment of lung cancer essential, the study also shows the importance of early diagnosis of GERD.

The new study features in the latest edition of the Cancer Medicine Journal.