Low-dose cisplatin-5-fluorouracil prevents postoperative suppression of natural killer cell activity in patients with gastrointestinal cancer

BACKGROUND: The effect of administering low-dose cisplatin(CDDP)-5-fluorouracil (5-FU) postoperatively on the activity of the immunesystem is not known. To clarify the effect on natural killer (NK) cellactivity of treatment with low-dose CDDP-5-FU, we compared NK cell activityafter surgery for gastrointestinal cancer in patients treated with low-doseCDDP-5-FU, a bolus dose of mitomycin C (MMC) or no anticancer drug.METHODS: Sixty-two patients consisted of three groups: low-dose CDDP-5-FU(n = 15), MMC (n = 20) and no-drug (n = 27). Chemotherapy was initiatedimmediately after surgery. NK cell activity was measured on the day beforesurgery (pre-op) and on postoperative days 7 (POD7) and 21 (POD21).RESULTS: The NK cell activities of the CDDP-5-FU group were 37.7% atpre-op, 36.1% on POD7 and 33.6% on POD21. However, the NK cell activitiesin the no-drug and MMC groups were significantly decreased on POD7 (from36.6 to 24.8% and from 31.4 to 16.6%, respectively). The NK cell activityin the MMC group remained depressed on POD21 (18.6%) whereas that in theno-drug group recovered (31.6%). CONCLUSIONS: Consecutive administration oflow-dose CDDP-5-FU appears to be useful as postoperative adjuvantchemotherapy because of its preventive effect on NK cell suppression aftersurgery.