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-fl uorouracil (5-FU) postoperatively on the activity of the immune system is not known. To clarify the effect on natural killer (NK) cell activ ity of treatment with low-dose CDDP-5-FU, we compared NK cell activity after surgery for gastrointestinal cancer in patients treated with lo w-dose CDDP-5-FU, a bolus dose of mitomycin C (MMC) or no anticancer d rug. Methods: Sixty-two patients consisted of three groups: low-dose C DDP-5-FU (n = 15), MMC (n = 20) and no-drug (n = 27). Chemotherapy was initiated immediately after surgery. NK cell activity was measured on the day before surgery (pre-op) and on postoperative days 7 (POD7) an d 21 (POD21). Results: The NK cell activities of the CDDP-5-FU group w ere 37.7% at pre-op, 36.1% on POD7 and 33.6% on POD21. However, the NK cell activities in the no-drug and MMC groups were significantly decr eased on POD7 (from 36.6 to 24.8% and from 31.4 to 16.6%, respectively ). The NK cell activity in the MMC group remained depressed on POD21 ( 18.6%) whereas that in the no-drug group recovered (31.6%). Conclusion s: Consecutive administration of low-dose CDDP-5-FU appears to be usef ul as postoperative adjuvant chemotherapy because of its preventive ef fect on NK cell suppression after surgery.