Establishment and validation of a nomogram with intratumoral heterogeneity derived from 18F-FDG PET/CT for predicting individual conditional risk of 5-year recurrence before initial treatment of nasopharyngeal carcinoma

BMC Cancer. 2020 Jan 15;20(1):37. doi: 10.1186/s12885-020-6520-5.

Abstract

Background: Intratumoral heterogeneity has an enormous effect on patient treatment and outcome. The purpose of the current study was to establish and validate a nomogram with intratumoral heterogeneity derived from 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for prognosis of 5-Year progression-free survival (PFS) of patients with nasopharyngeal carcinoma (NPC).

Methods: A total of 171 NPC patients who underwent pretreatment 18F-FDG PET/CT were retrospectively enrolled. Data was randomly divided into training cohort (n = 101) and validation cohort (n = 70). The clinicopathologic parameters and the following PET parameters were analyzed: maximum and mean standardized uptake value (SUVmax, SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and heterogeneity index (HI, SUVmax/SUVmean) for primary tumor and maximal neck lymph node. Cox analyses were performed on PFS in the training cohort. A prognostic nomogram based on this model was developed and validated.

Results: For the primary tumor, MTV-2.5, TLG-2.5, MTV-70%, and TLG-70% were significantly correlated with PFS. For the maximal neck lymph node, short diameter and HI were significantly correlated with PFS. Among the clinicopathologic parameters, M stage was a significant prognostic factor for recurrence. In multivariate analysis, M stage (P = 0.006), TLG-T-70% (P = 0.002), and HI-N (P = 0.018) were independent predictors. Based on this prognostic model, a nomogram was generated. The C-index of this model was 0.74 (95% CI: 0.63-0.85). For the cross validation, the C-index for the model was 0.73 (95% CI: 0.62-0.83) with the validation cohort. Patients with a risk score of ≥111 had poorer survival outcomes than those with a risk score of 0-76 and 77-110.

Conclusions: Intratumoral heterogeneity derived from 18F-FDG PET/CT could predict long-term outcome in patients with primary NPC. A combination of PET parameters and the TNM stage enables better stratification of patients into subgroups with different PFS rates.

Keywords: Nasopharyngeal carcinoma; Nomogram; Positron emission tomography computed tomography; Progression-free survival; Radiotherapy.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Fluorodeoxyglucose F18*
  • Follow-Up Studies
  • Humans
  • Kaplan-Meier Estimate
  • Middle Aged
  • Nasopharyngeal Carcinoma / diagnostic imaging*
  • Nasopharyngeal Carcinoma / mortality
  • Nasopharyngeal Carcinoma / pathology*
  • Nasopharyngeal Carcinoma / therapy
  • Neoplasm Staging
  • Nomograms
  • Positron Emission Tomography Computed Tomography* / methods
  • Positron Emission Tomography Computed Tomography* / standards
  • Prognosis
  • Proportional Hazards Models
  • Recurrence
  • Reproducibility of Results
  • Young Adult

Substances

  • Fluorodeoxyglucose F18