ILD Associated With Increased Risk for Lung Cancer

TOPLINE:

Individuals with interstitial lung disease (ILD) had more than a 13-fold higher incidence rate of lung cancer than those without ILD. The association persisted after adjustment for confounders, was consistent across all histological subtypes, and remained elevated even 10 years after ILD diagnosis.

METHODOLOGY:

• ILD is a progressive chronic lung disease previously linked to a suspected incidence of lung cancer. However, no study has comprehensively analyzed the risk for lung cancer in patients with ILD after controlling for genetic factors.
• This cohort study included 5,425,976 individuals (51.2% men) from the Swedish Total Population Register; of these, 14,624 had ILD (58.1% men; 65.9% aged > 40 years).
• The researchers conducted a sibling‐controlled analysis to account for genetic and early environmental factors. This involved 9157 individuals with ILD and at least one full sibling and 21,725 unaffected full siblings.
• The primary outcome was lung cancer diagnosis. The follow-up spanned from 1987 to 2016.

TAKEAWAY:

• The incidence rate of lung cancer was significantly higher among patients with vs without ILD (355.4 vs 26.2 per 100,000 person-years).
• After adjusting for confounders, the risk for lung cancer remained higher among individuals with ILD (hazard ratio [HR], 2.16). The sibling-controlled analysis also revealed a higher risk for lung cancer (HR, 2.91).
• When stratified by histological subtypes, an elevated risk for lung cancer was observed for adenocarcinoma (HR, 1.60), squamous cell carcinoma (HR, 2.56), and small cell carcinoma (HR, 3.29).
• Including the first 3 years of follow-up, ILD was associated with a higher risk for lung cancer, and this increased risk persisted even 10 years post-diagnosis (HR, 2.08).

IN PRACTICE:

“Our findings indicate that ILD is associated with an elevated risk of lung cancer, even after adjusting for familial factors” and “an increased risk of various histological subtypes of lung cancer,” the authors wrote. “These findings suggest that the presence of ILD should be incorporated into lung cancer risk assessment models,” they added.

SOURCE:

This study, led by Hui Xu, MD, Karolinska Institutet, Stockholm, Sweden, was published online in JAMA Network Open.

LIMITATIONS:

The study lacked detailed smoking history and relied on diagnoses of smoking-related diseases as proxies, which may have led to residual confounding. The number of lung cancer cases in some ILD subtypes was too small for detailed subtype-specific analyses. Additionally, the study could not assess tumor location, limiting anatomical correlation between ILD and lung cancer.

DISCLOSURES:

This study was supported by a grant from the Swedish Cancer Society. The authors reported having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.