Alveolar Soft Tissue Sarcoma: Correlation of MRI Features With Histological Grading and Patient Prognosis.

Background: Alveolar Soft Part Sarcoma (ASPS) is a rare, aggressive cancer whose diagnosis and treatment depend on histological grading. However, tumor variability can lead to underestimation, affecting treatment, and patient survival.

Objective: To evaluate MRI features associated with Grade III ASPS and to determine the relationship between MRI features and patient prognosis.

Study type: Retrospective analysis.

Subjects: Sixty-seven patients with ASPS were included with 37 males and 30 females (M/F = 1.23) follow-up and survival analysis on 50 patients.

Field strength/sequence: A 3.0 T, T1WI-FSE, T2WI-FSE, DWI-EPI, DCE-MRI (gradient echo).

Assessment: MRI features (margin, peritumoral oedema, peritumoral enhancement, necrosis, vascular flow void signal, heterogeneous signal intensity [SI] at T1WI and T2WI, ADCmean, time-intensity curve [TIC] type, distant metastasis, and bone invasion) and histological grading were independently evaluated by three radiologists and two pathologists, with Grade III considered high-grade.

Statistical tests: The chi-square or Fisher's exact test was used to assess the correlation between MRI features and histological grading. Multivariable binary logistic regression identified independent factors associated with high-grade tumors. The Kaplan-Meier method and Cox proportional hazards model were used to calculate hazard ratios for MRI features.

Results: Tumor necrosis, heterogeneous SI at T2WI ≥50%, and ADCmean were associated with high-grade ASPS. Tumor necrosis was an independent factors associated with local relapse-free survival (odds ratio [OR], 3.88). TIC type was associated with 5-year survival rate (OR, 2.80) and local relapse-free survival (OR, 2.69). Heterogeneous SI at T2WI ≥50% was associated with 5-year survival (OR, 4.00), local relapse-free survival (OR, 5.58), and local relapse-free survival (OR, 4.84).

Data conclusion: MRI features including tumor necrosis, heterogeneity of SI at T2WI, ADCmean, and TIC type aid in assessing ASPS grading and prognosis.

Evidence level: 4 TECHNICAL EFFICACY: Stage 5.