Routine Chest Scans Advised for IPF Patients as Lung Cancer Risk Evident, Study Says

Lung cancer is more likely in people with idiopathic pulmonary fibrosis (IPF) than the public at large, and these patients should be given regular chest scans for its presence, a study reports.

Routine use of high-resolution computed tomography (HRCT) chest scans is particularly important because lung cancer lowers an IPF patient’s life expectancy, its researchers wrote.

The study, “A nationwide population-based study of incidence and mortality of lung cancer in idiopathic pulmonary fibrosis,” was published in the journal Nature Scientific Reports.

Lung tissue in IPF patients is progressively scarred, making it hard for these people to breathe. Previous epidemiological studies have considered IPF to an independent risk factor for the development of lung cancer, with previous studies reporting that risk to be eight times higher than the general population after adjusting for smoking habits.

Yet, current clinical guidelines do not recommend that these patients be routinely screened for the presence of lung cancer.

“In the absence of an official recommendation for LC [lung cancer] screening in IPF, a large number of IPF patients are diagnosed with advanced LC at the time of hospital visit due to symptom development over several years,” the investigators wrote.

To generate evidence that would support the such guidelines, researchers in South Korea assessed the incidence and survival rates of lung cancer among people diagnosed with IPF.

The team used the National Health Insurance Service (NHIS), an health insurance database that contains information from around 50 million people, ages 40 and older living in South Korea between 2011 and 2016, to identify IPF patients and the incidence of lung cancer among them.

A total of 7,277 newly diagnosed IPF patients were in the researchers’ analyses, with their study covering the five years from 2012 through 2016. Most were men (72.8%) with a mean age of 71.5, living in rural areas of the country (55.2%).

Of this IPF group, 464 (6.4%) patients were diagnosed with lung cancer over these years. More than half (54.7%) of them were diagnosed with IPF before lung cancer was found.

IPF incidence increased throughout the study, rising from 2.5 cases per 100,000 people in 2012 to 3.8 cases per 100,000 people in 2016. The number of IPF patients diagnosed with lung cancer also increased over this period, from 32 cases in 2012 to 118 in 2016.

Likewise, lung cancer’s incidence among IPF patients initially without cancer rose from 1.7% at one year following their IPF diagnosis to 7.0% at year five. The time interval between these patients’ IPF and cancer diagnosis ranged from 8.2 to 28.8 months (a median of 16.3 months).

Statistical analyses confirmed that the survival rates of IPF patients with lung cancer were lower that those of IPF patients without cancer after one year — 65.5% vs. 78.5%, respectively. The same was true at two years — 44.2% in those with cancer and  67.8% for those without cancer.

“The 5-year survival rate was 15.6% in the IPF with LC group, which was significantly lower than that in the IPF without LC group,” the researchers wrote.

Additional analyses also identified the presence of lung cancer and patients’ age at the time of IPF diagnosis as two independent risk factors for mortality.

Based on the findings, investigators “concluded that IPF increases LC risk, and LC weakens survival outcomes in IPF.”

These data, they added, “suggest the need for close HRCT surveillance for LC in all IPF patients.”