AbstractThirty patients with a diagnosis of metastatic adenocarcinoma of the lung were entered on a trial to evaluate the antitumor efficacy of 5-fluorouracil 370 mg/m2daily for 5 days every four weeks in combination with folinic acid 200 mg/m2, 60 mm prior to 5FU. All patients had a good performance status, bidimensionally measurable disease, and weight loss≤5% of preillness weight. Of the 29 evaluable patients, only two (7%) had partial responses (95% confidence limits 1–24%). Eleven (38%) had stable disease and 16 (55%) progressed. The two responding patients survived 12 and 60+ weeks. The median survival of all evaluable patients was 25 weeks (range 7–60+) and that of the stable patients was 26 weeks. The principal toxicities observed were diarrhea and stomatitis. Myelosuppression was rarely dose limiting. In contrast to the results of treatment with 5FU and folinic acid in metastatic colorectal cancer and breast cancer, the results of treatment with this combination of agents have been much less encouraging in adenocarcinoma of the lung.