Prognostic Significance of the Standardized Uptake Value on Positron Emission Tomography in Patients with Multiple Clinical-N0 Lung Cancers.

Abstract

While there have been many attempts to differentiate multiple lung cancers (MLCs) using the clinicopathological presentation and molecular profile, there are still some controversies regarding the prognostic factors for MLCs with clinical-N0 status. Between 1996 and 2012, 131 patients were diagnosed as MLCs pathologically. The main lesion of MLCs was defined as follows: (1) among synchronous lesions, the radiologically denser or larger tumor on thin-section computed tomography (CT) or (2) the second tumor among metachronous lesions. (18)F-fluorodeoxyglucose uptake on positron emission tomography (PET) scan was examined to evaluate maximum standardized uptake value (SUVmax) of the main tumor. Among 131 patients with clinical-N0 status, 66 were men and 65 were women and they had an average age of 67 years. One-hundred nine patients were diagnosed as MPLCs, and 22 were intrapulmonary metastases (PMs). Based on multivariate analyses, SUVmax was a significant prognostic factor in both synchronous and metachronous clinical-N0 MLCs (p = 0.0060, 0.0451, respectively). Among the overall patients, while pathological diagnosis, maximum tumor dimension, consolidation status, and SUVmax were all significant prognostic factors by a univariate analysis, SUVmax (p = 0.0016) was superior to pathological diagnosis based on the Martini and Melamed classification (p = 0.2258) based on a multivariate analysis. The 5-year survival rate of MPLCs (78.7%) was significantly greater than that of PMs (30.5%) (p = 0.0036). Furthermore, the 5-year survival rate in patients with low SUVmax (91.1%) was far better than that in patients with high SUVmax (17.9%) (p = 0.0001). SUVmax on PET was a significant clinical factor that more precisely reflected the prognosis of MLCs with clinical-N0 status, and could be superior to a pathological diagnosis based on the Martini and Melamed classification.