Real‐world study of treatment and outcome of type B2 + B3 thymoma: The neglected part of thymoma

BACKGROUND: This study aimed to examine the treatment and prognosis of patients with type B2 + B3 thymoma and compare it with those patients with type B2 and B3 thymoma. METHODS: We conducted a retrospective analysis of the results of 39 patients with type B2 + B3 thymoma, 133 patients with type B2 thymoma, and 64 patients with type B3 thymoma. The Kaplan–Meier technique was used to generate survival curves. For multivariate analysis, the Cox proportional hazard model was applied. RESULTS: With a median follow‐up of 60 months (range: 1–128 months), the percentage of patients with tumor, node, metastasis (TNM) stage III and IV disease gradually increased from 19.5% to 25.6% to 35.9% among those with histological subtypes B2, B2 + B3, and B3, respectively, p = 0.045. Twenty‐three patients experienced recurrence or metastasis. The total 10‐year progression‐free survival (PFS) rates were 86.0% overall (85.0% in type B2, 87.2% in type B2 + B3, and 87.5% in type B3). Age, R0 resection, and Masaoka–Koga stage were found to have a significant on PFS in all patients. There was no statistically significant difference in PFS between different histotypes of thymoma, p = 0.650. PFS was predicted by R0 resection in all histotypes and by the Masaoka–Koga stage in the type B2 subgroup. CONCLUSION: Combining the two staging methods to guide the diagnosis and treatment of patients with B2 + B3 thymoma is recommended. R0 resection is recommended to reduce recurrence. Patients with B2 + B3 thymoma have a prognosis similar to those with a B2 thymoma or a B3 thymoma alone.