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Teaching pack: Thymoma and thymic carcinoma

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9 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.

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  1. Teaching pack · Cancer · thoracic

    Thymoma and thymic carcinoma

    Thymoma and thymic carcinoma are rare tumours of the thymus gland in the chest. Thymomas grow slowly, often cause autoimmune diseases such as myasthenia gravis, and are usually cured by surgery; thymic carcinomas behave like other aggressive cancers and have few effective drugs.

    Teaching pack: Thymoma and thymic carcinoma · OnCo, CC BY 4.0 · not medical advice1 / 9
  2. What it is

    In two paragraphs

    Thymic epithelial tumours range from indolent thymomas (WHO types A, AB, B1-B3) to thymic carcinoma (type C, mostly squamous) and thymic neuroendocrine tumours. Thymomas have the lowest tumour mutational burden of any adult cancer (GTF2I L424H in ~40% of type A/AB) and are uniquely associated with paraneoplastic autoimmunity (myasthenia gravis in ~30%, pure red cell aplasia, hypogammaglobulinaemia/Good syndrome). Staging uses Masaoka-Koga and the TNM 8th edition (ITMIG/IASLC).

    Complete resection is the treatment for resectable disease, with post-operative radiotherapy for stage II-III thymoma with high-risk features and for thymic carcinoma. Unresectable disease is treated with induction chemotherapy (cisplatin-doxorubicin-cyclophosphamide, CAP, or carboplatin-paclitaxel for thymic carcinoma) followed by surgery or radiotherapy. Recurrent disease is treated with re-resection where possible, chemotherapy, octreotide plus prednisone for octreoscan-positive thymoma, and in thymic carcinoma with sunitinib or lenvatinib (REMORA). PD-1 inhibitors show activity in thymic carcinoma (pembrolizumab ~20% response) but cause severe immune-related adverse events, especially myocarditis and myositis, and are avoided in thymoma. Everolimus and KIT inhibitors (for the ~10% of thymic carcinomas with KIT mutations) are options.

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  3. Standard of care

    What is given today, by setting

    SettingApproachGuideline
    Resectable (stage I-III)Complete thymectomy (minimally invasive for small tumours) after myasthenia control; post-operative radiotherapy for stage III, R1/R2, or thymic carcinoma.NCCN Category 2A
    Locally advanced unresectableInduction chemotherapy (CAP or carboplatin-paclitaxel) then surgery if resectable, otherwise definitive radiotherapy ± chemotherapy.NCCN Category 2A
    Recurrent thymomaRe-resection of pleural or local recurrence; chemotherapy; octreotide + prednisone if octreoscan-positive; everolimus.NCCN Category 2A
    Recurrent thymic carcinomaSunitinib or lenvatinib (REMORA); pembrolizumab (with strict cardiac monitoring, not in thymoma); everolimus; KIT inhibitors for KIT-mutant disease.NCCN Category 2A
    Teaching pack: Thymoma and thymic carcinoma · OnCo, CC BY 4.0 · not medical advice3 / 9
  4. State of the art

    Where the field stands

    • Surgery cures most thymomas; the ITMIG global database and TNM staging (2017) standardised a field once defined by single-centre series.
    • Multikinase inhibitors are the only agents with prospective phase 2 evidence in thymic carcinoma.
    • Immunotherapy is a double-edged sword: responses in thymic carcinoma, but life-threatening myocarditis and myositis, and contraindication in thymoma.
    • Thymoma's near-absence of mutations and its autoimmune phenotype make it a model for understanding tolerance.
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  5. History

    How we got here

    1. 1939Blalock: thymectomy improves myasthenia gravis
    2. 1981Masaoka staging system
    3. 1999WHO histologic classification of thymic epithelial tumours
    4. 2010ITMIG founded; global retrospective database
    5. 2014GTF2I mutation discovered in thymoma (Petrini, Nat Genet)
    6. 2015Sunitinib active in thymic carcinoma (Thomas, Lancet Oncol)
    7. 2017TNM 8th edition staging (IASLC/ITMIG)
    8. 2018Pembrolizumab in thymic carcinoma: activity with severe irAEs (Giaccone, Lancet Oncol)
    9. 2020REMORA: lenvatinib in thymic carcinoma
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  6. Pipeline

    What is coming

    • Lenvatinib (product)
    • Sunitinib (product)
    • Pembrolizumab (product)
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  7. Open problems

    What nobody has solved

    • No randomised trials have ever been completed in thymic epithelial tumours.
    • Immunotherapy safety in a tumour that disturbs central tolerance.
    • Thymic carcinoma metastatic disease: median survival ~2-3 years.
    • Management of paraneoplastic syndromes alongside cancer therapy.
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  8. Quiz

    Check understanding

    1. What is the standard treatment for stage II-III triple-negative breast cancer today?
      Answer
      Neoadjuvant pembrolizumab with carboplatin/paclitaxel then anthracycline chemotherapy, surgery, and adjuvant pembrolizumab (KEYNOTE-522); adjuvant olaparib for germline BRCA carriers with residual disease (OlympiA); capecitabine for residual disease without BRCA.
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  9. Sources

    Read the primary sources

    • NCCN Guidelines: Thymomas and Thymic Carcinomas: https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1469
    • ITMIG: https://itmig.org/
    • NCI PDQ: thymoma and thymic carcinoma: https://www.cancer.gov/types/thymoma/patient/thymoma-treatment-pdq
    • Wikipedia: https://en.wikipedia.org/wiki/Thymoma
    • Guideline: https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1469
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