Cavity Wall Thickness in Solitary Cavitary Lung Adenocarcinomas Is a Prognostic Indicator

Although cavitary lung cancers typically show thick-walled cavities on radiology, thin-walled cancers have recently been reported. However, the prognostic and pathologic differences between thin-walled and thick-walled variants are unclear. We reviewed detailed histologic features and survival outcomes of cavitary pulmonary adenocarcinomas to assess pathologic attributes, focusing particularly on cavity wall thickness.

We studied 132 patients diagnosed with lung adenocarcinoma involving cavitary formation, as determined with high-resolution computed tomography or histology, between 1998 and 2007. Using receiver-operating characteristics curve analysis, we established a cutoff value for cavity wall thickness based on disease-specific survival. Cavitary adenocarcinomas were grouped into thick-walled or thin-walled types according to this cutoff, as measured by computed tomography.

The thick-walled group comprised lung adenocarcinoma patients with a cavity wall thickness of greater than 4 mm (n = 65); the thin-walled group comprised patients with a cavity wall thickness of 4 mm or less (n = 67). The thick-walled group had a higher frequency of solid predominant tumors (p < 0.01), vascular invasion (p < 0.001), lymphatic invasion (p < 0.01), necrosis (p < 0.001), obstructive pneumonia (p < 0.01), intracavity abscess (p < 0.01), and bronchiolar obstruction (p = 0.02). Lepidic predominant (p = 0.09) and papillary predominant patterns (p = 0.08) were more common in the thin-walled group. Multivariate analysis revealed cavity wall thickness to be an independent prognostic factor (p = 0.022).

The pathologic and prognostic implications of thick-walled cavities versus thin-walled cavities in lung carcinoma patients, defined according to our cutoff, were found to be distinct.