Thymoma: treatment and prognosis

Thirty-six patients with pathologically confirmed thymoma were treated at M.D. Anderson Cancer Center from 1962 to 1987. The tumors were staged based on invasion and intrathoracic dissemination. Twenty-one patients had total resection, five had subtotal resection, and 10 had biopsy alone. Twenty-two patients had definitive megavoltage radiation therapy with a median dose of 50 Gy. The 5-year, disease-free survival by stage was 74% for Stage I (n = 11), 71% for Stage II (n = 8), 50% for Stage III (n = 10), and 29% for Stage IVA (n = 7) (p less than 0.03). The 5-year, disease-free survival by extent of surgery was 74% for total resection, 60% for subtotal resection and 20% for biopsy only (p = 0.001). There were 15 patients with recurrences: two in Stage I, two in Stage II, five in Stage III, and six in Stage IVA. The median months to relapse, for those who failed treatment, were 46, 36, 2, and 13 for Stages I, II, III, and IVA respectively. Of the patients with recurrences four had a total resection, two subtotal resection, and nine biopsy only. Only one patient had distant metastases as the first site of relapse without intrathoracic relapse. For the eight patients who relapsed following radiation therapy, four were in the radiotherapy field. All four of the in-field failures were in patients who had a partial response. There were insufficient numbers of patients to determine a dose response to radiotherapy. For patients with invasive, incompletely resected disease, a multimodality approach may be necessary for long term, disease-free survival.