Prognostic nomogram for overall survival in pediatric osteosarcoma with pulmonary metastases: a SEER database analysis

Abstract

Background: Pulmonary metastasis (PM) is the most common site of distant metastasis in osteosarcoma (OS), particularly in pediatric cases, which are associated with poor prognosis. However, limited research has focused on identifying prognostic factors (PFs) for pediatric osteosarcoma with pulmonary metastasis (POPM). This study aims to identify clinical features and PFs of POPM and develop a validated nomogram to predict overall survival in POPM patients.

Methods: A retrospective analysis was conducted using OS cases from the Surveillance, Epidemiology, and End Results (SEER) database (2010-2021). Clinical characteristics were compared between patients with and without PM. PFs were identified using Least Absolute Shrinkage and Selection Operator (LASSO) regression and evaluated through Kaplan-Meier analysis. Patients were divided into training (N = 148) and validation (N = 64) cohorts. Independent PFs were determined via Cox regression to construct a prognostic nomogram, which was assessed using the concordance index (C-index), the area under the receiver operating characteristic curve (AUC-ROC), and calibration plots. Decision curve analysis (DCA) was used to evaluate clinical applicability.

Results: LASSO regression identified key PFs: AJCC stage, T stage, median household income, systemic therapy, and time from diagnosis to treatment. Among these, all except T stage were validated as independent PFs via Cox regression. The nomogram demonstrated strong predictive accuracy with C-index values of 0.68 (training) and 0.71 (validation). AUC values for 1-, 3-, and 5-year survival were 0.786, 0.709, and 0.711 in the training cohort and 0.780, 0.760, and 0.776 in the validation cohort. Calibration plots showed excellent concordance between predicted and actual survival, and DCA confirmed the nomogram's clinical relevance.

Conclusion: AJCC stage, median household income, systemic therapy, and time from diagnosis to treatment are significant PFs for POPM survival. The validated nomogram provides a valuable tool for personalized prognostic assessment and treatment decision-making in clinical practice.

Keywords: nomogram; osteosarcoma; pediatric osteosarcoma; prognosis; pulmonary metastasis.

Figure 1

Optimal cutoff values for age, tumor size, and time from diagnosis to treatment identified using X-tile. (A,B) Determination of optimal age cutoff values. (C) Kaplan–Meier survival curves for age subgroups (0–17 years and 18–19 years). (D,E) Determination of optimal tumor size cutoff values. (F) Kaplan–Meier survival curves for tumor size subgroups (<8.8 cm and ≥8.8 cm). (G,H) Determination of optimal cutoff values for time from diagnosis to treatment (days). (I) Kaplan–Meier survival curves for time-to-treatment subgroups (<5 days and ≥5 days).

Figure 2

Flowchart illustrating patient selection based on inclusion and exclusion criteria.

Figure 3

Feature selection using LASSO regression analysis. (A) Coefficient profiles of clinical variables plotted against Log(λ), where each colored line represents a variable. (B) Ten-fold cross-validation for tuning parameter selection. The vertical dashed line indicates the value of λ corresponding to the minimum partial likelihood deviance, representing the optimal model fit.

Figure 4

Kaplan–Meier curves illustrating overall survival. (A) Lung metastasis. (B) AJCC stage. (C) T stage. (D) Median household income. (E) Systemic therapy. (F) time from diagnosis to treatment in days.

Figure 5

Nomogram for predicting 1-, 3-, and 5-year overall survival in pediatric osteosarcoma patients with pulmonary metastasis.

Figure 6

ROC curves of the nomogram predicting 1-, 3-, and 5-year overall survival in pediatric osteosarcoma patients with pulmonary metastasis. (A) ROC curves for the training group. (B) ROC curves for the validation group.

Figure 7

Calibration curves for the nomogram predicting 1- (A,D), 3- (B,E), and 5-year (C,F) overall survival in the training group and the validation group.

Figure 8

Decision curves for the nomogram predicting 1-, 3-, and 5-year overall survival in pediatric osteosarcoma patients with pulmonary metastasis. (A) Decision curves for the training group. (B) Decision curves for the validation group.