A study was conducted to evaluate the impact of cisplatin, doxorubicin, cyclophosphamide and etoposide (PACE) with granulocyte colony-stimulating factor (G-CSF) on advanced thymoma or thymic cancer. Between August 1989 and December 1994, 14 patients with invasive, metastatic or recurrent thymoma or thymic cancer were treated with cisplatin (80 mg/m2, on day 1), doxorubicin (45 mg/m2, on day 1), cyclophosphamide (800 mg/m2, on day 1) and etoposide (80 mg/m2, on day 1-3) with G-CSF (90 micrograms/m2, on day 5-18) at the National Cancer Center Hospital, Tokyo. Courses were repeated every 3 or 4 weeks for a maximum of 4 cycles. Twelve patients were treated with 2 or more courses of PACE. Two patients were treated with only one course, one refused and another required emergency thoracic radiotherapy after one course of PACE. Six patients had partial responses (3 thymomas and 3 thymic cancers) but there were no complete remissions (response rates, 42.9%; 95% confidence interval, 17.7% to 71.1%). Moderate hematological toxicities were observed: grade 3 or 4 leukopenia, neutropenia, anemia and thrombocytopenia in 10, 13, 8 and 6 patients, respectively. Six patients developed infections that required antibiotics. Surgical resection or thoracic radiotherapy after PACE treatment was performed in 2 and 7 patients, respectively. The overall median survival time was 14.7 months (range, 5.9 to 59.7 months). For 9 patients who had received no prior treatment before chemotherapy, the median survival time was 8.9 months, and one patient survived for 4 years and is still alive. In conclusion, PACE with G-CSF frequently produces objective remissions in patients with advanced thymoma or thymic cancer. A large-scale intergroup study is necessary to determine the impact of this regimen on advanced thymoma and thymic cancer.