Significance of the Lesion-Pleura Relationship in Differentiating Peripheral Inflammatory Lesions and Lung Cancers.

Purpose: To determine the significance of lesion-pleura relationship in differentiating peripheral inflammatory lesions (PILs) and peripheral lung cancers (PLCs).

Patients and methods: From January 2017 to April 2022, a total of 743 patients with 501 PLCs and 292 PILs (≥1.5 cm) were retrospectively enrolled. The patients' clinical characteristics and CT features of lesions in these two groups were analyzed and compared, and the impact of the lesion-pleura relationship (broad or narrow basement and distance between lesion and pleura) on differentiation was specifically assessed.

Results: Lesions attached to pleura were more frequent in PILs (188, 64.4%) than in PLCs (244, 48.7%) (P < 0.001), and those with broad basement-to-pleura were also more common in PILs (133, 70.7%) than in PLCs (47, 19.3%) (P < 0.001). Among the 296 lesions with a lesion-pleura distance ≤16 mm, the optimal cutoff value of distance was ≤8.9 mm (area under curve [AUC], 0.733; sensitivity: 0.770; specificity: 0.623; P < 0.001) for predicting PLCs. Regarding the 728 lesions attached to pleura or with a lesion-pleura distance ≤16 mm, the AUC of the model based on the clinical and CT features for predicting PLCs significantly increased from 0.812 to 0.879 after including lesion-pleura relationship (narrow basement or lesion-pleura distance ≤ 8.9 mm) (P < 0.001). Additionally, the lesion-pleura relationship was one of independent indicators for differentiation (odds ratio, 9.433; P < 0.001).

Conclusion: When differentiating peripheral lesions (≥1.5 cm), it is crucial to consider the basement-to-pleura and lesion-pleura distance besides patients' clinical characteristics, laboratory parameters and morphological features.