AbstractDetailed records were maintained prospectively of all medications taken by 719 patients with advanced carcinoma of the lung or colon. Of this total, a cohort of 19 patients was identified who had ingested incidentally either nifedipine, diltiazem, verapamil, or trifluoperazine in standard therapeutic doses for a minimum of one month and a mean of 5.8 months and median of three months. Treatment with these calcium antagonists was well tolerated and, upon comparison with otherwise comparable patients who did not ingest a calcium antagonist, appeared to be associated with certain favorable outcomes, including delayed tumor progression and prolonged survival. These preliminary findings suggest that beneficial effects of such drugs observed with chronic treatment in experimental animal tumor models may occur in human disease and that definitive prospective, randomized, clinical trials of calcium antagonists administered continuously in ordinary therapeutic doses are both feasible and justified.