Revisiting prognosis of oligodendroglioma patients in the 2021 WHO classification: incremental value of imaging features.

OBJECTIVES

To investigate whether imaging factors can improve the prediction of progression-free survival (PFS) in patients with oligodendroglioma over clinicopathological features.

MATERIALS AND METHODS

A total of 180 patients diagnosed and treated for oligodendroglioma (IDH-mutant and 1p/19q codeleted) between 2005 and 2021 were included. Clinical data and preoperative MRI images were analyzed for qualitative and quantitative characteristics. Qualitative features included tumor location, calcification, gliomatosis cerebri pattern, cystic change, necrosis, and infiltrative pattern, while quantitative features included total, contrast-enhancing (CE), non-enhancing, and necrotic tumor volumes via automatic segmentation. Significant predictors of PFS were identified using univariable and multivariable Cox analyses. Two prognostic models were developed: model 1 (clinicopathological features) and model 2 (addition of imaging features). The prognostic value of the two models was compared.

RESULTS

On univariable analysis, male sex, gliomatosis cerebri pattern, larger total tumor, CE tumor, and non-enhancing tumor volumes, and partial resection or biopsy were unfavorable predictors of PFS. On multivariable analysis, male sex (hazard ratio (HR) = 3.76, p = 0.012), larger CE tumor volume (HR = 1.06, p = 0.003) and partial resection or biopsy (HR = 6.83, p = 0.001) remained as unfavorable predictors for PFS. Compared with the clinicopathological model, the model adding imaging feature demonstrated a higher C-index (0.784 vs. 0.776) and iAUC (0.745 vs. 0.725), with a significantly high time-dependent AUC for PFS at 1 year (0.989 vs. 0.943, p = 0.001).

CONCLUSION

The CE tumor volume on preoperative MRI is an independent prognostic factor in oligodendroglioma patients, potentially guiding follow-up and adjuvant treatment decisions.

KEY POINTS

Question This study examines whether imaging factors can improve the prediction of progression-free survival (PFS) in patients with oligodendroglioma over clinicopathological features. Findings Larger contrast-enhancing (CE) tumor volume, male sex, and lesser resection independently predicted shorter PFS. Incorporating CE tumor volume improved model performance over clinicopathological features alone. Clinical relevance The clinicopathological and imaging features were comprehensively investigated in patients with oligodendroglioma to predict PFS. Incorporating CE tumor volume improved the model's predictive performance, providing valuable information for clinical decision-making in identifying high-risk patients.