Decedents with idiopathic pulmonary fibrosis (IPF) demonstrated a 53% lower probability of comorbid lung cancer contributing to their underlying cause of death compared to those without IPF, according to results of a new study published in the European Respiratory Journal of Open Research.

In the US, 35,615,442 deaths occurred between 2004 and 2018 as listed in the Centers for Disease Control and Prevention Multiple Cause of Death database. Of these deaths, 3.38% of decedents had comorbid lung cancer and IPF, while 6.90% of decedents had lung cancer without IPF.

“Since both [lung cancer] and IPF have a short survival time, the lower prevalence reported in these studies and ours is likely to be because those with [lung cancer] or IPF die before the other condition can develop,” the authors said.


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Lung cancer was significantly less prevalent in those with IPF irrespective of age, race, and sex; however, between 2010 and 2018, the odds of comorbid lung cancer with IPF trended upward from 0.43 in 2010 to 0.58 in 2018.

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The underlying cause of death was lung cancer in 94.2% of individuals who had lung cancer without IPF. The underlying cause of death was 20.8% in IPF and lung cancer and in 75.9% of individuals with comorbid lung cancer and IPF.

In the comorbid patient population, the authors attributed the increase in IPF as the underlying cause of death due to many patients with IPF experiencing pneumonia and/or an acute exacerbation prior to death. Therefore, medical personnel documented IPF instead of lung cancer as the primary cause of death.

Researchers calculated the mortality rate due to lung cancer as 132 in every 100,000 deaths. The lung cancer mortality rate decreased in all individuals without IPF, as well as in those with IPF aged between 65 and 74 years. In contrast, the mortality rate increased in people of Hispanic ethnicity and people 75 and older with comorbid IPF and lung cancer.

The authors acknowledged the possibility of under-reporting and misdiagnosis for IPF as well as under-reporting of early-stage lung cancer. Lack of data regarding IPF disease duration made it difficult to determine whether longer durations increased lung cancer prevalence compared with shorter durations.

Reference

Jeganathan N, Cleland D, Sathananthan M. The association of lung cancer with pulmonary fibrosis. ERJ Open Research. 2022;8(1). doi:10.1183/23120541.00505-2021