Exercise therapy effect on natural killer cell cytotoxic activity in stomach cancer patients after curative surgery

Objective: To evaluate the effect of early exercise therapy on the natural killer cell cytotoxic activity (NKCA) of patients who had undergone curative resection of stomach cancer. Design: Prospective study. Patients: Thirty-five stomach cancer patients who had undergone curative surgery were randomly divided into an exercise group (n = 17) and a control group (n = 18). Intervention: From postoperative day 2, moderated exercise using arm and bicycle ergometers performed twice a day, 5 times a week, for 14 days. The intensity of exercise was 60% of maximal heart rate. Venous blood samples were obtained on postoperative days 1, 7, and 14. Main Outcome Measure: Mean sequential change of NKCA. Results: The mean sequential change of NKCA decreased until postoperative day 7 and then increased. Mean NKCA of day 7 decreased in both groups, compared with that at postoperative day 1. At day 14, the mean NKCA of the exercise group demonstrated a significant increase compared with that of the control group (p < .05). Conclusion: This study suggests that early moderate exercise has a beneficial effect on the function of in vitro NK cells in stomach cancer patients after curative surgery.