A thymoma diagnosis raises specific questions that few non-specialist teams encounter often. The histological subtype matters. The Masaoka-Koga stage matters. The decision between immediate surgery, neoadjuvant chemotherapy, and multimodality treatment depends on a careful reading of imaging and pathology against the published recommendations of the International Thymic Malignancies Interest Group (ITMIG). Many patients are referred for a second opinion before committing to treatment — at this practice, that is a routine part of the work, not an exception. Dr Okiror offers private thymoma surgery and second-opinion consultations at London Bridge Hospital and The Lister Hospital Chelsea.
Last reviewed: April 2026 · Dr Lawrence Okiror FRCS(CTh) FRCSEd(CTh) · GMC 6150382
The thymus is a small gland in the front of the chest, behind the breastbone, that plays a central role in the development of the immune system in early life. In adulthood it becomes largely inactive — but in some adults it gives rise to tumours. These are called thymic epithelial tumours, and they are rare: approximately two cases per million people per year.
Thymomas are not all the same. The World Health Organization classifies them into six types — A, AB, B1, B2, B3, and thymic carcinoma (sometimes called Type C) — reflecting increasing biological aggressiveness. Type A and AB tend to behave indolently. Type B2 and B3 are higher-grade. Thymic carcinoma behaves more like other aggressive cancers and has a fundamentally different treatment pathway.
Histological subtype, together with the Masaoka-Koga stage, determines the treatment plan. Both must be confirmed by an experienced thoracic pathologist before any treatment is recommended. If either has not been clearly established at diagnosis, that is the first thing a specialist consultation should resolve.
A thymoma diagnosis is not a single clinical entity with a single treatment. The right operation — or whether surgery comes first at all — depends on histological subtype, the precise Masaoka-Koga stage, and the assessment of whether complete (R0) resection is achievable. Four broad clinical scenarios cover the majority of patients, and each has a different evidence base and pathway.
Masaoka-Koga Stage I & II
Curative-intent surgery · ITMIG & NCCN recommended pathway
For encapsulated and minimally invasive thymomas, surgery is the primary treatment and offers an excellent chance of cure. Five-year survival is 89–100% for Stage I and 71–97% for Stage II after complete resection. Robotic extended thymectomy — removing the thymus en-bloc with the surrounding mediastinal fat between both phrenic nerves and the innominate vein, per ITMIG technical recommendations — is well-established for these stages.
For Stage II disease with capsular invasion, post-operative radiotherapy may be considered depending on margins, histological subtype, and individual MDT recommendation.
Masaoka-Koga Stage III
Neoadjuvant chemotherapy · surgery · post-operative radiotherapy
For tumours invading the pericardium, lung, or great vessels, immediate surgery may not achieve complete resection. The standard pathway is neoadjuvant cisplatin-based chemotherapy — most commonly CAP (cyclophosphamide, doxorubicin, cisplatin) or PE (cisplatin, etoposide) — followed by surgery if R0 resection becomes feasible, then post-operative radiotherapy.
Some Stage III tumours are directly resectable without neoadjuvant treatment. The decision is made at MDT after detailed review of imaging, considering the tumour's relationship to critical structures and the likelihood of achieving complete resection at first operation.
Masaoka-Koga Stage IVA
Pleural/pericardial spread · specialist surgical capability required
Stage IVA disease — with pleural or pericardial dissemination — was traditionally considered unresectable. International experience now shows that, in selected cases, extended resection within a multimodality regimen can achieve excellent long-term survival. This may include pericardial resection, partial lung resection, vascular reconstruction, or pleurectomy/decortication for diffuse pleural disease.
These cases require a centre with both thoracic surgical experience in advanced thymoma and immediate access to cardiac surgical support for cases where reconstruction of major vascular structures is required.
High-Grade B3 & Thymic Carcinoma
Chemotherapy · radiotherapy · surgery · emerging immunotherapy role
Type B3 thymoma and thymic carcinoma behave more aggressively than lower-grade thymomas. Treatment is almost always multimodality — integrating platinum-based chemotherapy, radiotherapy, and surgery — sequenced according to stage and resectability. Five-year survival for thymic carcinoma is around 30%, considerably lower than for thymoma overall.
The role of checkpoint inhibitor immunotherapy is emerging in this group specifically — covered separately below, with important caveats about autoimmune side effects unique to thymic tumours.
A note on the evidence base
Thymoma is rare. There are no large randomised controlled trials in thymoma surgery comparable to those that exist in lung cancer. International recommendations — from ITMIG, NCCN, and ESMO — are based on registry analyses, prospective cohort studies, and consensus expert opinion. This is acknowledged honestly in those guidelines, and it is one reason why every thymoma patient benefits from review at a centre that sees the full spectrum of disease.
Complete (R0) resection is the strongest predictor of long-term survival in thymoma. The clinical question at every consultation is whether complete resection is achievable now, achievable after neoadjuvant treatment, or unlikely to be achievable at all.
Stage I and II thymomas. Encapsulated or minimally invasive disease. Complete resection achievable robotically with a single operation. The vast majority of these patients will not require chemotherapy. Some Stage II tumours benefit from post-operative radiotherapy depending on margins and histology.
Stage III tumours with major vascular or pericardial invasion where R0 resection is doubtful at first operation. Stage IVA with limited pleural disease. Neoadjuvant chemotherapy — typically three cycles of CAP or PE — can shrink the tumour and increase the likelihood of complete resection at the subsequent operation.
Stage IVB disease with distant metastases or extensive lymph node involvement — treated with systemic therapy. Diffuse pleural disease where pleurectomy/decortication cannot achieve meaningful clearance. Patients whose comorbidities make extended thoracic surgery unsafe. In these cases, an honest conversation about realistic goals matters more than offering an operation.
At consultation, Dr Okiror reviews CT and PET-CT imaging personally, examines the histopathology report against ITMIG diagnostic criteria, and where relevant requests review by a dedicated thoracic pathologist. Every thymoma patient is discussed at a chest multidisciplinary team meeting before any operation is recommended — including, where useful, virtual consultation with the international ITMIG tumour board.
Every thymoma patient under Dr Okiror's care is discussed at a multidisciplinary team meeting before any treatment is recommended. The team includes thoracic surgery, medical oncology, radiation oncology, thoracic radiology, and histopathology. Where relevant, a respiratory physician and a specialist neurologist for myasthenia gravis are also part of the discussion.
For complex cases — particularly Stage IVA disease, recurrent thymoma, or unusual histology — the MDT may also involve consultation with the ITMIG virtual tumour board, an international forum specifically created so that centres without dedicated thymoma expertise can access specialist opinion. ITMIG explicitly recommends this for complex cases. Dr Okiror's practice routinely uses this resource where it adds value.
Every patient with a thymoma diagnosis is also assessed for myasthenia gravis. Approximately 30–50% of thymoma patients have or develop MG, and current NCCN guidance (2024) explicitly requires this clinical assessment in every thymic tumour case. Where MG is identified, the perioperative pathway changes substantially. See MG thymectomy page →
In selected Stage III and IVA cases where the tumour involves the superior vena cava or other major vascular structures, surgery is performed in collaboration with cardiac surgical colleagues. These cases are uncommon, but they are precisely the operations that distinguish a specialist thymoma centre from a general thoracic practice.
Immunotherapy has transformed the treatment of many cancers over the past decade. Patients diagnosed with thymoma understandably want to know whether this applies to them. The answer is genuinely nuanced — and it differs significantly between thymoma and thymic carcinoma.
Thymic tumours frequently express PD-L1 — a target for checkpoint inhibitor drugs such as pembrolizumab and nivolumab. PD-L1 positivity is reported in 23–92% of thymomas and 36–100% of thymic carcinomas. On paper, this should make them excellent candidates for immunotherapy. In practice, the picture is more complicated, because the thymus itself is central to immune tolerance — the mechanism that prevents the immune system from attacking the body's own tissues. Thymoma involves defective immune tolerance. When checkpoint inhibitors release the brakes on the immune system, thymoma patients have significantly higher rates of severe immune-related side effects than any other solid tumour. Myositis, myocarditis, and multisystem autoimmune inflammation are disproportionately common.
For thymoma (Types A through B2), this means checkpoint inhibitors are not routine treatment. They are not part of standard first-line or adjuvant care. They may be considered in carefully selected recurrent or refractory cases at specialist centres, with intensive monitoring for autoimmune side effects.
For Type B3 thymoma and thymic carcinoma, the evidence is more developed. Pembrolizumab in pre-treated thymic carcinoma has shown overall response rates of approximately 25% and durable benefit in a subset of patients, with high tumour PD-L1 expression associated with better response. The PECATI trial presented at ESMO 2024 reported that pembrolizumab combined with lenvatinib achieved a median progression-free survival of 14.9 months in pre-treated B3 thymoma and thymic carcinoma — a meaningful result in this difficult disease group, though immune-related toxicity required close monitoring.
Decisions about immunotherapy in any thymic tumour are made jointly with a medical oncologist with thymic-specific experience, after careful review of histology, prior treatment, and the individual risk profile. They are never made unilaterally, and they should never be made without specialist input.
Thymoma is a rare tumour. Many hospitals across the UK see only one or two cases a year. This makes individual surgeon and unit experience an unusually important consideration when choosing where to be treated.
The 2024 SCTS national audit reports that the thoracic surgical unit at Dr Okiror's NHS base performs over 10% of all thymectomies across the United Kingdom and Ireland — the highest single-centre volume of thymic surgery in the country. This is published institutional data from the Society for Cardiothoracic Surgery, not an internal claim. The same operative approach, the same MDT framework, and the same standard of perioperative care apply to private patients seen at London Bridge Hospital and The Lister Hospital Chelsea.
Dr Okiror's personal experience covers the full thymoma spectrum — from robotic thymectomy for early-stage tumours through to multimodality management of Stage III and IVA disease, including cases requiring vascular reconstruction. Patients have included international referrals for second opinion and for surgery. As Clinical Audit Lead for Thoracic Surgery, Dr Okiror is responsible for the submission and verification of the unit data referenced above.
Dr Okiror consults and operates at both London Bridge Hospital and The Lister Hospital Chelsea. Both hold the da Vinci Xi robotic platform and are appropriate settings for robotic thymectomy in Stage I and II disease.
For Stage III and IVA cases — particularly those requiring multimodality treatment, extended resection, or vascular reconstruction — surgery takes place at London Bridge Hospital, where the level of perioperative support and access to cardiac surgical colleagues match the complexity of the operation.
Outpatient consultations are also available at HCA clinics in Canary Wharf and the City of London. International patients who travel specifically for thymoma assessment can be accommodated, and remote review of imaging and histology can be arranged before travel.
Insurance and self-pay: Dr Okiror is recognised by all major UK private medical insurers including AXA, BUPA, WPA, Vitality, Cigna, and Aviva. Self-pay and international patients are equally welcome. Multimodality treatment may involve several components and prolonged care — transparent estimates are provided by Jo Mitchelson before any commitment is made — 020 7952 2882 or pa@lungsurgeon.co.uk.
For a tumour as rare as thymoma, the variation in treatment recommendations between centres can be substantial. Three questions are reasonable before committing to any plan, and any thoughtful surgical team should welcome them.
Both must be clearly established before a treatment plan is finalised. If your team has not given you a specific WHO type (A, AB, B1, B2, B3, or thymic carcinoma) and a specific Masaoka-Koga stage, ask why. Treatment for Type A Stage I differs fundamentally from treatment for B3 Stage III, and neither should be planned without clarity on both.
A general thoracic MDT may see one or two thymomas a year. ITMIG — the international thymic tumours interest group — recommends virtual tumour board consultation for centres without dedicated thymic expertise. Asking whether your case has been reviewed by specialists who see thymoma at volume is a clinically appropriate question.
For Stage III and IVA disease, the sequence — whether neoadjuvant chemotherapy comes first, whether immediate surgery is appropriate, whether radiotherapy is part of the plan — matters greatly for outcomes. Each component should be justified against the imaging findings and the specific WHO subtype, not chosen by default.
A second opinion appointment with Dr Okiror is typically available within 2–3 days. Bring your CT, PET-CT, biopsy report, and any treatment recommendation already received.
If your thymoma comes with myasthenia gravis
Thymomatous MG requires a more complex pathwayAround 30–50% of thymoma patients have myasthenia gravis. The oncological indication for thymectomy is independent of the MG — but the perioperative pathway, the choice of anaesthesia, and the post-operative monitoring all change substantially when MG is present. The dedicated MG thymectomy page covers this in detail.
Common questions from patients and families newly diagnosed with thymoma or thymic carcinoma, and from those seeking a specialist second opinion before committing to a treatment plan.
Book a Consultation →Or call Jo Mitchelson:
020 7952 2882
Appointments within 2–3 days. Self-referrals and international referrals welcome. Surgery at London Bridge Hospital and The Lister Hospital Chelsea.
Jo Mitchelson, Private PA · 020 7952 2882 · pa@lungsurgeon.co.uk
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Robotic thymectomy for myasthenia gravis — the MGTX evidence, perioperative pathway, and antibody-based patient selection
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Robotic Thoracic SurgeryThe full robotic thoracic surgery service — thymectomy, lobectomy, segmentectomy, and complex resection