What is the recommended treatment approach for a patient diagnosed with thymoma?

Thymoma Treatment: Stage-Based Algorithmic Approach

Complete surgical resection via open median sternotomy is the cornerstone of thymoma treatment, with the specific treatment algorithm determined entirely by disease stage at presentation. 1, 2

Stage I Disease

Perform complete surgical resection of the entire thymus without any neoadjuvant or adjuvant therapy. 1

• Use open median sternotomy as the standard surgical approach 2
• Remove the entire thymus including perithymic fat from phrenic nerve to phrenic nerve laterally and from diaphragm to thyroid gland superiorly 2
• No radiation or chemotherapy is needed after complete resection 1

Stage II Disease

Perform complete surgical resection via open median sternotomy, then selectively add adjuvant radiation only for high-risk features. 1

• For Stage IIA with complete resection, do not routinely use adjuvant radiation 1, 2
• Add adjuvant radiation for high-risk features including: capsular invasion (Stage IIB), close surgical margins, WHO grade B histology, or tumor adherent to pericardium 1
• Do not use postoperative or neoadjuvant systemic chemotherapy for Stage II disease 1
• For medically inoperable patients, use chemoradiation or radiation alone 1

Critical pitfall: Radiation carries long-term risks of secondary malignancies and coronary artery disease, particularly problematic in younger patients who may survive decades—discuss these risks explicitly before proceeding. 1

Stage III Disease

Evaluate all patients for multimodality therapy combining neoadjuvant chemotherapy, surgical resection, and adjuvant chemoradiotherapy. 1, 2

Stage IIIA Approach:

• Perform surgery either initially or after neoadjuvant therapy, aiming for complete resection with wide margins 1
• If preoperative assessment suggests incomplete resection is likely, give neoadjuvant chemoradiation before surgery 1

Stage IIIB Approach:

• Assess for surgery only after neoadjuvant chemoradiotherapy 1
• For bulky tumors, use sequential chemotherapy followed by radiation rather than concurrent therapy 1
• For small treatment volumes, concurrent chemoradiotherapy is acceptable 1

Neoadjuvant Regimen Specifics:

• Use cisplatin-based combination chemotherapy, with cisplatin plus anthracycline combinations having the most clinical experience 1
• Establish tissue diagnosis via CT-guided core-needle biopsy or open surgical biopsy before starting neoadjuvant therapy 1

Surgical Technique for Advanced Disease:

• If complete resection is impossible at thoracotomy, perform maximal debulking with vascular reconstruction as needed 1
• Place surgical clips to mark residual tumor for targeted adjuvant radiation 1
• Never resect both phrenic nerves—this causes severe respiratory morbidity that devastates quality of life 1, 2

Adjuvant Therapy:

• Give adjuvant radiotherapy after resection (this is standard practice) 1
• Adjuvant chemotherapy may be considered but insufficient data exists to routinely recommend it after complete resection 1

Unresectable Stage III:

• When surgery is inappropriate, use chemotherapy concurrent with or sequential to radiation 1
• Unresectable disease is defined as extensive tumor involving trachea, great arteries, and/or heart that has not responded to cisplatin-based chemotherapy 1

Stage IVA Disease

Apply the same Stage III recommendations, but only perform surgery if pleural and pericardial metastases can be completely resected. 1

• Surgery should achieve complete resection of both primary tumor and all metastatic deposits 1
• Neoadjuvant chemoradiotherapy is an option 1
• Use cisplatin-based combination chemotherapy regimens 1
• Adjuvant chemoradiotherapy is an option after resection 1
• For unresectable disease with extensive pleural/pericardial metastases, use chemotherapy alone or combined with radiation 1
• Cisplatin plus anthracycline-containing regimens are most commonly used as first-line therapy 1

Stage IVB Disease

Treat on an individual case basis—no generic recommendations exist due to poor prognosis and limited evidence. 1

Recurrent Disease

Consider surgery, radiation, and/or chemoradiation based on location and extent of recurrence. 1

• Use chemoradiation for all medically inoperable and technically inoperable patients 1

Radiation Therapy Technical Standards

• Deliver 45-70 Gy to the primary tumor bed depending on margin status 2
• Limit total cardiac dose to ≤30 Gy given younger patient age and long survival expectations 2

Critical Perioperative Consideration

Screen all patients for myasthenia gravis before any surgical procedure, even if asymptomatic, to prevent perioperative respiratory failure. 2

• Myasthenia gravis occurs in approximately 40% of thymoma patients and requires specific perioperative management 3

Surveillance Protocol

Perform chest CT with contrast every 6 months for 2 years, then annually until 10 years. 2

• Thymomas have a tendency for late recurrence even after complete resection, necessitating prolonged surveillance 1