Visceral plural invasion (VPI) is a significant predictor of survival in patients with small solid lung tumours but not in patients with part-solid tumours, Japanese study findings indicate.
Kenji Suzuki and colleagues, from Juntendo University School of Medicine in Tokyo, explain that although VPI “has long been recognized as an adverse prognostic factor” in non-small-cell lung cancer (NSCLC), its impact in tumours with ground-glass opacity (GGO) lesions, including those with a part-solid appearance, is controversial because of their minimally invasive nature.
To better understand the significance of VPI in these types of tumours, Suzuki and team retrospectively reviewed thin-section computed tomography (CT) scans from 446 patients (mean age 66 years, 50.4% men) with surgically resected, node-negative part-solid or pure-solid NSCLC less than 30 mm.
A part-solid nodule (n=237) was defined as a tumour with focal nodular opacity that contained both solid and GGO components (consolidation/tumour ratio of 0 to <1.0), whereas a pure-solid nodule (n=209) showed consolidation without GGO.
The researchers report in TheAnnals of Thoracic Surgery that VPI was present in 24 (10%) part-solid nodules and 79 (38%) pure-solid nodules.
On multivariate analysis, VPI, along with vessel invasion, maximum tumour diameter and carcinoembryonic antigen level, significantly and independently predicted overall survival in patients with pure-solid nodules. Indeed, the 5-year survival rate in patients with pure solid-nodules with VPI (70.1%) was significantly worse than that in patients without VPI (81.3%).
By contrast, VPI was not a significant predictor of overall survival in patients with part-solid nodules, but consolidation/tumour ratio and carcinoembryonic antigen level were.
In this group, the 5-year survival rates in patients with and without VPI were 85.6% and 94.9%, respectively.
These findings suggest that “VPI plays a completely different role in each subtype of early-stage NSCLC based on the findings of thin-section CT scan”, Suzuki et al remark.
They say that this is important because the presence of VPI “increases the T staging factor from T1 to T2 and upstages a tumour from stage IA to stage IB pathologically,” which in turn may affect a clinician’s decision to administer adjuvant chemotherapy.
“Thus, upgrading of TNM staging and the administration of postoperative chemotherapy on the basis of pleural factors should not be considered in lung cancer patients with GGO predominance”, the team concludes.
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