New research shows the lollipop sign, spiculation and volume doubling time (VDT) are independent predictors on computed tomography (CT) scans for angiolymphatic invasion in patients with solid non-small cell lung cancer (NSCLC).
For the prospective study, recently published in Radiology, researchers reviewed chest CT data from 778 patients (median age of 69) who had resected NSCLCs < 30 mm. Solid tumors comprised 92 percent (715) of the reviewed NSCLCs with the remaining eight percent (63) being subsolid tumors, according to the study.
The study authors found that angiolymphatic invasion occurred in 37.9 percent of the cases involving solid NSCLCs but none of the cases of subsolid NSCLCs.
The researchers also determined that the lollipop sign was associated with a greater than a fourfold likelihood of angiolymphatic invasion in patients with solid NSCLCs < 30 mm.
“The lollipop sign was readily identifiable on preoperative CT images, offering a straightforward diagnostic indicator that does not require measurements. This sign intuitively reflects the status of the cancer nodule and adjacent blood vessels, making it a potentially valuable CT predictor of (angiolymphatic invasion) for solid NSCLCs 30 mm or smaller,” wrote Qi Sun, M.D., Ph.D., who is affiliated with the Department of Radiology at the Harbin Medical University Cancer Hospital in Hsrbin, China, and colleagues.
Multivariable analysis also revealed that spiculation on chest CT was associated with more than double the likelihood for angiolymphatic invasion in this patient population, according to the study authors.
“Spiculation, an irregular and spiculated appearance of tumor margin, is a radiologic feature associated with invasive components at pathologic examination. It likely serves as the most direct CT feature of the tumor itself that is indicative of direct invasion into normal tissues,” added Sun and colleagues.
While VDT data was only available for 474 cohort participants, the researchers noted that adding VDT to the predictive model for angiolymphatic invasion resulted in an 82 percent area under the receiver operating characteristic curve (AUC) in comparison to a 77 percent AUC for the lollipop sign and spiculation.
Three Key Takeaways
1. Lollipop sign as a predictor. The lollipop sign on CT scans is associated with a more than fourfold likelihood of angiolymphatic invasion (ALI) in solid non-small cell lung cancer (NSCLC) < 30 mm, offering a straightforward and intuitive diagnostic indicator.
2. Spiculation Indicates Invasiveness. Spiculation, characterized by irregular tumor margins, doubles the likelihood of ALI, serving as a strong radiologic feature of invasive tumor behavior.
3. Volume doubling time (VDT) as a predictor. Shorter VDT is associated with higher aggressiveness and likelihood of ALI in early-stage NSCLCs.
The study authors pointed out that patients with a combination of NSCLC and angiolymphatic invasion had shorter VDT in comparison to those without angiolymphatic invasion (203 days vs. 336.7 days).
“Our findings indicate that VDT was a predictor of ALI for early-stage NSCLCs. As tumor aggressiveness increases, so does the likelihood of ALI in the surrounding lung parenchyma,” noted Sun and colleagues.
(Editor’s note: For related content, see “CT Study Links Five-Year Prognosis with Minor Ground Glass Opacity Component in NSCLC Lung Nodules,” “Dual-Energy CT Improves Diagnosis of Metastatic Lymph Nodes with Non-Small Cell Lung Cancer” and “Can Radiomics Bolster Low-Dose CT Prognostic Assessment for High-Risk Lung Adenocarcinoma?”)
In regard to study limitations, the authors acknowledged the lack of VDT information for 241 of the cohort patients and conceded the model’s overall sensitivity rate remained suboptimal (64 percent) even after the incorporation of VDT. The researchers added that dividing the relatively small cohort into training, test sets and validation likely underpowered the analysis.
