br Materials and methods This retrospective
Materials and methods This retrospective analysis was approved by the Institutional Review Board of Seoul National University Hospital, and the requirement of written informed consent was waived. Our study Tunicamycin (572/572) was reported previously . In the prior study, we compared the prognostic performances of clinical T categorization between the longest and average diameter measurements on CT scans. The current study analyzed the prognostic implication of SUVmax as a complementary T factor for clinical staging.
Discussion Our results revealed that SUVmax was an independent predictor of DFS in patients with surgically treated stage I lung adenocarcinomas. SUVmax could be utilized as an independent and complementary T factor (PETT category) in conjunction with the clinical T category of the eighth-edition staging system. The addition of a PETT factor significantly improved the model’s fit for survival prediction. In addition, we demonstrated that the PETT category could be used to upshift or downshift the clinical T category, which led to the improved prognostic discrimination of lung adenocarcinomas. A recent multivariable, pooled meta-analysis of individual data, which assessed 1563 patients in 11 studies, showed that the addition of SUV to a model built using conventional prognostic factors, including age, stage, tumor size, and surgical treatment, was statistically significant . The adjusted HR of the dichotomous SUV category (high vs. low; median cutoff) was 1.58 (95% CI: 1.27, 1.96; P < 0.001) . This meta-analysis, which included studies published in the early 2000s, was published before the implementation of the eighth-edition staging system, the T coding system of which is strikingly different from the previous editions. Furthermore, the usage of either the clinical or the pathological staging system is also unclear. Nevertheless, in this study, it was concluded that SUV was a potential independent prognostic marker in patients with stage I-III non-small cell lung cancers (NSCLCs). Several prior meta-analyses reached similar conclusions, suggesting the potential of SUV for the prognostication of NSCLCs [, , ]. In the seventh or earlier editions of the TNM staging system, the total tumor size was used, including ground-glass opacity, for determining the clinical T category. However, it was revised to the solid portion size based on study results showing that the solid portion size was more closely associated with patients’ prognosis than the total tumor size was [10,, , ]. At present, in the circumstances where the solid portion size has a direct association with SUVmax [, , ], there should be doubt regarding whether the SUVmax of the primary tumor could contribute to the preoperative evaluation of lung adenocarcinomas. However, the results of our study demonstrated that SUVmax, as either a continuous or a categorical variable, could act as an independent prognostic factor in the revised staging system. The addition of the proposed PETT category significantly improved prognostication, and it was a useful parameter for the reclassification of the tumors. Thus, we cautiously suggest that the proposed PETT category could be integrated in the current lung cancer staging system, and it could be used as a nonanatomical element in prognostication beyond the conventional TNM classification . A plausible explanation of the significance of SUVmax (or PETT category) along with the solid portion size-based T categorization is its association with subtypes of adenocarcinomas [29,30]. According to Nakamura et al. , SUVmax values were the highest in micropapillary predominant adenocarcinomas, followed by solid predominant, invasive mucinous, acinar predominant, papillary predominant, and lepidic predominant adenocarcinomas. Recent studies showed that patients with micropapillary or solid predominant adenocarcinomas had significantly poorer survival [, , ]. Therefore, the integration of SUVmax in the current staging system may enable subdividing adenocarcinomas in the same clinical T category according to their inherent biological characteristics.