Prognostic impact of tumor size on patients with neuroblastoma in a SEER-based study

Objective The prognostic value of tumor size in neuroblastoma (NB) patients has not been fully evaluated. Our purpose is to elucidate the prognostic significance of tumor size in surgery performed on neuroblastoma patients. Methods Neuroblastoma patients diagnosed from 2004 to 2015 were selected from the Surveillance, Epidemiology, and End Results Program (SEER) for the study. Univariate and multivariate Cox proportional hazard regression models were used to identify risk factors and the independent prognostic influences of tumor size on NB patients. Overall survival (OS) was analyzed through univariate Cox regression analysis. To determine the optimal cutoff value of tumor size, we first divided the cohort into three groups (<= 5 cm, 5-10 cm, >10 cm). Subsequently, the patients were divided into two groups repeatedly, with tumor size at 1 cm intervals. The cutoff value that maximized prognostic outcome difference was selected. Furthermore, we performed the Kaplan-Meier methods to visually present differences in prognosis between the optimal tumor size cutoff value in different subgroups. Results A total of 591 NB patients who met the inclusion criteria were selected from the SEER database in this study. Cox analysis showed that age >1 year (HR = 2.42, p < 0.0001), originate from adrenal site (HR = 1.7, p = 0.014), distant stage (HR = 6.4, p < 0.0001), undifferentiated grade (HR = 1.94, p = 0.002), and large tumor size (HR = 1.5, p < 0.0001) independently predicted poor prognosis. For tumor size, there were significant differences in tumor size distribution in different ages, tumor grade, disease stage, and primary site subgroup but not in sex, race, and histology subgroup. Furthermore, both univariate (HR = 4.96, 95% CI 2.31-10.63, p < 0.0001) and multivariable analysis (HR = 2.8, 95% CI 1.29-6.08, p < 0.0001) indicated the optimal cutoff value of tumor size was 4 cm for overall survival of NB patients. Using a 4 cm of tumor size cutoff in subgroups, we found that it can identify poor prognosis patients whatever their age or primary site. Interestingly, tumor size of 4 cm cutoff can only identify unfavorable NB patients with diagnosis at distant-stage disease, or differentiated grade tumor, but not with regional and local or undifferentiated tumor. Conclusions Tumor size is first to be recognized as a key prognostic factor of neuroblastoma patients and a cutoff value >4 cm might predict poor prognosis, which should be included in the evaluation of prognostic factors for NB.