Incidence
Thymic tumours are very uncommon in comparison with other thoracic tumours. Thymomas account for 17% - 30% of anterior mediastinal tumours. The incidence is 0.18 per 100,000 for men and 0.10 per 100,000 for women.

Age and Gender
Thymomas affect both sexes equally and are most often seen in the 5^th and 6^th decades of life.

Survival 
The long-term survival rate for completely resected non-invasive thymomas is over 95%. Completely excised capsular-invaded or minimally invasive tumours treated with postoperative radiotherapy should have a 5-year survival rate of approximately 80%. More extensive but non-metastatic tumours may have a 40-50% control rate. Metastatic and recurrent thymomas have variable virulence and may respond to systemic therapy. Median survival is 2-4 years and 5-year survival is 25-30%.