Predictors of survival in patients with locally advanced thymoma and thymic carcinoma (Masaoka stages III and IVa)

Abstract

Objective: We sought to evaluate factors influencing long-term survival of patients with locally advanced thymoma/thymic carcinoma (Masaoka stages III and IVa) treated by immediate surgery or induction therapy plus surgery.

Methods: From January 1991 to April 2007, we surgically treated 61 patients with locally advanced thymoma/thymic carcinoma (Masaoka stages III and IVa). Staging included total body computed tomography (CT) scan in all patients, and chest magnetic resonance imaging (MRI) in 27 selected patients. All patients had histological confirmation before surgery. Thirty-one patients (group A) underwent induction chemotherapy followed by surgery. Thirty patients (group B) underwent immediate surgery. Thirty-four patients (group A: 13; group B: 17) received postoperative radiation therapy.

Results: No intra-operative mortality was reported. World Health Organization (WHO) histological classification included 19 AB, four B1, seven B2 and 13 B3 thymomas and 18 thymic carcinomas. Thirty-four patients were Masaoka stage III (group A: 18; group B: 16) and 27 patients were stage IVa (group A: 13; group B: 14). After a median follow-up of 77 months, six patients of group A and seven patients of group B died of disease. The overall 10-year survival rate was 50.6%. The 10-year survival rate was 57.9% in group A and 38.1% in group B (p=0.03). Multivariate analysis showed complete resection (p=0.02), Masaoka stage (III vs IVa) (p=0.02), induction chemotherapy (group A vs group B) (p=0.003) and histological WHO subtype (AB vs B1, B2 and B3) (p=0.01) to be statistically significant independent predictors of survival. Sex, age and adjuvant radiation therapy showed no statistically significant difference.

Conclusions: Complete resection, Masaoka stage, induction chemotherapy and histological WHO classification showed to be independent predictors of survival in locally advanced thymoma/thymic carcinoma.