Objectives To evaluate diagnostic delays in lung cancer among patients with interstitial lung disease (ILD), assess tumor characteristics and outcomes, and identify radiologic factors contributing to missed or delayed detection. Materials and methods In this retrospective study, 54 ILD patients with concurrent lung cancer from two tertiary ILD referral centers were reviewed. A panel of four thoracic radiologists determined the earliest callable date—when the majority would have raised concern about a nodule—compared to the date of first clinical suspicion. Tumor size, morphology, staging, growth rate (volume doubling time), treatment regimens, and survival were analyzed. For delayed cases, radiologic causes of missed detection were categorized by consensus. Results Diagnostic delays occurred in 50% of cases (27/54), with a mean delay of 3.18 years (IQR: 0.94–4.51). Delayed cases showed significantly slower tumor growth (mean volume doubling time: 1.42 vs. 0.22 years, p < 0.0001). The most common radiologic factors contributing to missed detection were obscuration by fibrosis, ground-glass opacity, or bronchovascular bundles (63%), misinterpretation as infection or exacerbation (15%), minimal interval growth (11%), and invisibility on CT (15%). Tumor size, morphology, stage, and histologic subtype—most commonly adenocarcinoma (56%)—were similar between groups. No significant difference in survival was observed between delayed and non-delayed cases (χ² = 0.4, p = 0.5). Conclusion Half of the lung cancer cases in ILD patients were diagnosed with significant delay, primarily due to parenchymal masking and subtle imaging findings, rather than biologically aggressive disease. Despite delays, survival outcomes and tumor characteristics did not differ significantly, suggesting a less aggressive tumor phenotype in delayed cases. Key Points <Emphasis Type="BoldItalic">Question</Emphasis> To evaluate diagnostic delays in lung cancer among patients with interstitial lung disease (ILD), assess tumor characteristics and outcomes, and identify radiologic factors contributing to missed or delayed detection. <Emphasis Type="BoldItalic">Findings</Emphasis> Half of lung cancer cases in ILD patients had diagnostic delays, mainly due to parenchymal masking. Delayed cases showed slower growth but no survival difference; tumor size and histology were indifferent. <Emphasis Type="BoldItalic">Clinical relevance</Emphasis> This study shows that lung cancer diagnosis is often delayed in ILD patients (avg. > 3 years). Clinicians should stay alert for malignancy in peripheral fibrotic regions with slow-growing nodules. Despite no clear survival impact, future work should assess the risks and benefits of earlier detection. Graphical Abstract

Assessment of delays in diagnosis of lung cancer in interstitial lung disease

期刊论文
发表日期：

2025年9月24日

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Tician Schnitzler,
Ali Nowroozi,
Maya Vella,
Jonathan Liu,
Shravan Sridhar,
Erica Farrand,
Jae Ho Sohn

摘要

Objectives

To evaluate diagnostic delays in lung cancer among patients with interstitial lung disease (ILD), assess tumor characteristics and outcomes, and identify radiologic factors contributing to missed or delayed detection.

Materials and methods

In this retrospective study, 54 ILD patients with concurrent lung cancer from two tertiary ILD referral centers were reviewed. A panel of four thoracic radiologists determined the earliest callable date—when the majority would have raised concern about a nodule—compared to the date of first clinical suspicion. Tumor size, morphology, staging, growth rate (volume doubling time), treatment regimens, and survival were analyzed. For delayed cases, radiologic causes of missed detection were categorized by consensus.

Results

Diagnostic delays occurred in 50% of cases (27/54), with a mean delay of 3.18 years (IQR: 0.94–4.51). Delayed cases showed significantly slower tumor growth (mean volume doubling time: 1.42 vs. 0.22 years, p < 0.0001). The most common radiologic factors contributing to missed detection were obscuration by fibrosis, ground-glass opacity, or bronchovascular bundles (63%), misinterpretation as infection or exacerbation (15%), minimal interval growth (11%), and invisibility on CT (15%). Tumor size, morphology, stage, and histologic subtype—most commonly adenocarcinoma (56%)—were similar between groups. No significant difference in survival was observed between delayed and non-delayed cases (χ² = 0.4, p = 0.5).

Conclusion

Half of the lung cancer cases in ILD patients were diagnosed with significant delay, primarily due to parenchymal masking and subtle imaging findings, rather than biologically aggressive disease. Despite delays, survival outcomes and tumor characteristics did not differ significantly, suggesting a less aggressive tumor phenotype in delayed cases.

Key Points

Question To evaluate diagnostic delays in lung cancer among patients with interstitial lung disease (ILD), assess tumor characteristics and outcomes, and identify radiologic factors contributing to missed or delayed detection.

Findings Half of lung cancer cases in ILD patients had diagnostic delays, mainly due to parenchymal masking. Delayed cases showed slower growth but no survival difference; tumor size and histology were indifferent.

Clinical relevance This study shows that lung cancer diagnosis is often delayed in ILD patients (avg. > 3 years). Clinicians should stay alert for malignancy in peripheral fibrotic regions with slow-growing nodules. Despite no clear survival impact, future work should assess the risks and benefits of earlier detection.

Graphical Abstract