Purpose: In prior Cancer and Leukemia Group B (CALGB) studies, combined chemotherapy and thoracic irradiation was superior to chemotherapy alone in limited-disease (LD) small-cell lung cancer (SCLC). A combined modality pilot study was performed to test the feasibility of adding warfarin to aggressive chemoradiotherapy for LD SCLC.
Patients and methods: Combination chemotherapy with doxorubicin 45 mg/m2 intravenously (IV) on day 1, cyclophosphamide 800 mg/m2 IV on day 1, and etoposide (ACE) 80 mg/m2 on days 1 to 3 was given every 21 days for the first three courses. The fourth and fifth courses substituted cisplatin 33 mg/m2 IV on days 1 to 3 for the doxorubicin, with concurrent chest irradiation to a total of 4,000 cGy given in 20 fractions during a 4-week period followed by a boost of 1,000 cGy in five fractions during a 1-week period. Prophylactic cranial irradiation, 3,000 cGy was given concurrently in 10 fractions during a 2-week period. Courses 6 to 8 again used ACE chemotherapy, but courses 4 to 8 were given on a 28-day schedule with dose adjustment for hematologic or renal toxicity. Warfarin was given throughout the treatment period titrated to achieve a prothrombin time (PT) of 1.5 to 2 times the control. Patients with histologically proven limited-stage SCLC, good performance status, and normal renal, hematologic, and hepatic functions were eligible.
Results: Sixty-one of 66 patients entered onto the study were eligible and assessable. Fifty-four (89%) (95%) confidence interval [CI], 78% to 95%) experienced an objective response, 35 (57%) achieved a complete response (CR) (95% CI, 44% to 70%), and 17 (28%) achieved a partial response (95% CI, 16% to 39%). Median durations were CR, 26.3 months; failure-free survival, 11.8 months; and survival, 18 months. Forty-one percent of the patients were alive at 2 years, 33% were alive at 3 years, and 25% were alive at 4 or more years. Median follow-up for survivors is 5 years (range, 3.5 to 5.9 years). Severe or life-threatening myelosuppression occurred in 90%, infection occurred in 34%, fever without documented infection occurred in 26%, and pulmonary toxicity occurred in 6%. Another 6% of patients experienced severe or life-threatening hemorrhages. There were four treatment-related fatalities. The pulmonary toxicities have been associated with the resumption of ACE chemotherapy after chest irradiation.
Conclusions: These highly encouraging response and survival results compare favorably with any prior CALGB group study. Although they are somewhat more toxic, they are comparable to the best published results. A randomized study that examines the role of warfarin is underway.