Prediction of visceral pleural invasion of clinical stage IA lung adenocarcinoma based on computed tomography features

Abstract

Background: In lung cancer, preoperative prediction of visceral pleural invasion (VPI) is helpful for choosing the best treatment plan and improving the prognosis of patients. This study aimed to investigate the usefulness of computed tomography (CT) features in predicting VPI in clinical stage IA peripheral lung adenocarcinoma (LUAD) with pleural contact.

Methods: This study divided the type of contact between tumor and pleura into indirect and direct contacts. This study retrospectively analyzed patients with clinical stage IA peripheral LUAD in three hospitals and enrolled 485 patients. The CT features of lesions were analyzed to predict VPI, including relative pleural features, tumor signs, and characteristics between the tumor and pleura. Univariate and multivariate logistic regression analyses were used to select the best combination of variables to predict VPI, and the prediction models were developed.

Results: The multivariate logistic regression analysis identified solid component size, pleural tag type, and vascular convergence sign to be independent risk factors for VPI in indirect pleural contact type. The area under curve (AUC) values of the model for predicting VPI in the training, internal validation, and external validation sets were 0.887, 0.799, and 0.862, respectively. Solid component size and pleural indentation sign were identified as independent risk factors for predicting VPI in direct pleural contact type. The AUC values of the model for predicting VPI in the training, internal validation, and external validation sets were 0.903, 0.848, and 0.842, respectively.

Conclusions: CT predictors associated with VPI differ based on the type of contact with the pleura. The multivariate logistic regression models utilizing CT features demonstrates acceptable diagnostic accuracy in predicting VPI in clinical stage IA LUAD with pleural contact.

Keywords: Lung cancer; adenocarcinoma; computed tomography (CT); prediction; visceral pleural invasion (VPI).

Figure 1

The flowchart of inclusion and exclusion criteria of patients. CT, computed tomography; DLP, distance between the lesion and the pleura; LUAD, lung adenocarcinoma; pGGNs, pure ground glass nodules.

Figure 2

The density changes of the pleura in indirect pleural contact type. (A) A 76-year-old man presented with mGGNs in the left upper lobe and fat density in the mediastinal pleural indentation (Type C). (B) A 54-year-old female presented with mGGNs in the left lower lobe and water density in the costal pleural indentation (Type D). (C) A 57-year-old female presented with mGGNs in the right upper lobe and soft tissue density in the costal pleural indentation (Type E). SD in figures means standard deviation of CT value. CT, computed tomography; mGGNs, mixed ground glass nodules.

Figure 3

The density changes of the pleura in direct pleural contact type. (A) A 59-year-old female presented with solid nodule in the left upper lobe and fat density in the costal pleural indentation (Type C). (B) A 55-year-old female presented with mGGNs in the right lower lobe and water density in the costal pleural indentation (Type D). (C) A 64-year-old man presented with solid nodule in the right upper lobe and soft tissue density in the costal pleural indentation (Type E). SD in figures means standard deviation of CT value. CT, computed tomography; mGGNs, mixed ground glass nodules.

Figure 4

The characteristics of the tumor and the pleura in indirect pleural contact type. (A,B) A 53-year-old man presented with mGGNs in the right upper lobe and tumor size is 21.9 mm (green line), solid component size is 15.8 mm (red line), and minimum vertical DLP is 4.64 mm. (C) A 43-year-old man presented with mGGNs in the right upper lobe and the edge of the tumor was flat and deformed, showing an arch bridge, which was the bridge sign, the line drawing on the upper left in (C) is the interpretation the bridge sign. (D) The tumor was connected to the pleura by thin line, without pleural indentation sign, which was the Rat-tail sign (Type I). (E) The tumor was connected to the pleura by the thin line with pleural indentation sign, which was the Fish-tail sign (Type II). (F) The tumor was connected to the pleura by a thick strip with pleural indentation sign, which was the Peacock-tail sign (Type III). The line drawings on the upper left in (D-F) are the interpretation of the classification of pleural tags sign. DLP, distance between the lesion and the pleura; mGGNs, mixed ground glass nodules.

Figure 5

The characteristics of the tumor and the pleura in direct pleural contact type. (A) A 64-year-old man presented with mGGNs in the right lower lobe and direct contact with the interlobar fissure with pleural indentation, with solid components contacting the pleura, the whole tumor contact length is 14.2 mm (green line), solid component contact length is 8.51 mm (red line). (B) A 49-year-old female presented with solid nodule in the right lower lobe, which directly contacted the adjacent costal pleura with a narrow base without pleural indentation, and the overall proportion of tumor contacting pleura was 47.62% (Type I). (C) A 73-year-old female presented with mGGNs in the left upper lobe, which directly contacted the adjacent costal pleura with a wide base without pleural indentation, and the overall proportion of tumor contacting pleura was 92.03% (Type II). (D) A 57-year-old female presented with solid nodule in the right middle lobe, which directly contacted the adjacent interlobar pleura with a narrow base with pleural indentation (red arrows), and the overall proportion of tumor contacting pleura was 38.29% (Type III). The tumor was associated with pleural tags sign (yellow arrow). (E) A 59-year-old female presented with solid nodule in the left upper lobe, which directly contacted the adjacent costal pleura with a wide base with pleural indentation, and the overall proportion of tumor contacting pleura was 55.35% (Type VI). The line drawings on the upper left in (B-E) are the interpretation of the classification based on the proportion of tumors contacting the pleura and pleura morphology. mGGNs, mixed ground glass nodules.