Thymoma
ICD-10 D15.0 · ICD-11 4B40.Y

Locally Advanced Thymoma (Masaoka-Koga Stage III/IVA) When Induction Chemotherapy Does Not Achieve Resectability

Clinical Scenario

This protocol applies to Masaoka-Koga stage III/IVA thymoma (TNM IIIA–IVA) in which complete resection was not deemed achievable upfront. After biopsy and primary induction chemotherapy, imaging is used to reassess whether the tumour has become operable. When that reassessment does not confirm resectability, a defined consolidation strategy guides the next step.

Staging & Resectability Context

In Masaoka-Koga stage III/IVA (classified as TNM IIIA/T3, IIIB/T4, or IVA in the IASLC/ITMIG system), complete resection is frequently not achievable upfront based on imaging. A biopsy is performed first, followed by induction chemotherapy as part of a curative-intent sequential strategy integrating subsequent surgery or radiotherapy.

Prior Treatment Line — Goal Not Reached

The preceding treatment used a cisplatin-based combination regimen — with anthracycline-based regimens preferred — administered for two to four cycles. The intended goal was for the tumour to become resectable on reassessment imaging. This protocol is for patients where that reassessment did not confirm adequate downstaging — the tumour remains unresectable or complete resection is still not feasible.

Consolidation Approach (Partial Overview)

Consolidation is guided by the response to induction. Both surgical and radiation-based interventions are relevant to this setting, and combined modality approaches may be considered in certain patients. The full selection criteria, sequencing, and regimen specifics are available in the complete protocol.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1093/annonc/mdv277

If complete resection is deemed not to be achievable upfront on the basis of imaging studies, as it is frequently the case in Masaoka-Koga stage III/IVA tumours (classified as stage IIIA/T3, IIIB/T4, /IVA in the IASLC/ITMIG TNM proposed system), a biopsy should be carried out, followed by primary/induction chemotherapy as part of a curative-intent sequential strategy that integrates subsequent surgery or radiotherapy.

Surgery should be offered to patients for whom complete resection is deemed achievable, according to principles discussed above [III, A]; extended resection may be required.

If the patient is not deemed a surgical candidate — either because R0 resection is not thought to be achievable, or because of poor performance status or co-existing medical conditions — definitive radiotherapy is recommended as part of a sequential chemoradiotherapy strategy [III, A].

Combination with chemotherapy (including cisplatin, etoposide chemotherapy and a total dose of radiation of 60–66 Gy in 30–33 fractions) may be considered [V, C].

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