Role of adjuvant radiotherapy for stage II thymoma after complete tumor resection

Int J Radiat Oncol Biol Phys. 2010 Dec 1;78(5):1400-6. doi: 10.1016/j.ijrobp.2009.09.066. Epub 2010 Apr 6.


Purpose: To determine whether patients with Masaoka stage II thymoma benefit from adjuvant radiation therapy after complete tumor resection.

Methods and materials: A total of 107 patients with stage II thymoma who underwent complete resection of their tumors between September 1964 and October 2006 were retrospectively analyzed. Sixty-six patients were treated with adjuvant radiotherapy, and 41 patients received surgery alone.

Results: Eight patients (7.5%) had a relapse of their disease, including two patients (4.5%) who had surgery alone, and 6 patients (9.5%) who had adjuvant radiation therapy. Disease-free survival rates at 5 and 10 years were 92.3% and 82.6%, respectively, for the surgery-plus-radiation group, and 97.6% and 93.1%, respectively, for the group that underwent surgery alone (p = 0.265). Disease-specific survival rates at 5 and 10 years were 96.4% and 89.3%, respectively, for the surgery-plus-radiation group and 97.5% and 97.5% for the surgery group (p = 0.973). On univariate analysis, patients with type B3 thymomas had the lowest disease-free survival rates among all subtypes (p = 0.001), and patients with large thymomas (>7 cm) had lower disease-specific survival rates than those with small tumors (<7 cm) (p = 0.017). On multivariate analysis, histological type (type B3) thymoma was a significant independent prognostic factor.

Conclusions: Adjuvant radiotherapy after complete tumor resection for patients with stage II thymoma did not significantly reduce recurrence rates or improve survival rates. Histological type (type B3) thymoma was a significant independent prognostic factor. Further investigation should be carried out using a multicenter randomized or controlled study.

MeSH terms

  • Adult
  • Analysis of Variance
  • Disease-Free Survival
  • Female
  • Humans
  • Male
  • Middle Aged
  • Neoplasm Recurrence, Local / mortality
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Staging
  • Radiotherapy, Adjuvant / adverse effects
  • Radiotherapy, Adjuvant / methods
  • Retrospective Studies
  • Thymoma / mortality
  • Thymoma / pathology
  • Thymoma / radiotherapy*
  • Thymoma / surgery*
  • Thymus Neoplasms / mortality
  • Thymus Neoplasms / pathology
  • Thymus Neoplasms / radiotherapy*
  • Thymus Neoplasms / surgery*