In a study using animal models, natural killer cell activity was suppressed by physical stress or surgery, resulting in a significant increase in tumor development. These findings suggest that protective measures should be considered to prevent metastasis for patients undergoing surgery to remove a cancerous tumor, according to Gayle Page, DNSc, RN, associate professor and Independence Foundation Chair at the Johns Hopkins School of Nursing. Human studies have already found a connection between the level of NK activity and susceptibility to several different types of cancer, says Page, an author of the study. We sought to determine the importance of stress-induced suppression of NK activity and thus learn the effects of stress and surgery on tumor development.
Many patients undergo surgery to remove cancerous tumors that have the potential to spread.
If our findings in rats can be generalized to such clinical settings, then these circumstances could increase tumor growth during or shortly after surgery. The research was conducted at Ohio State University College of Nursing and the Department of Psychology at UCLA, where Page held previous positions, and at Tel Aviv University. Results of the study are published in the March issue of the International Journal of Cancer. In laboratory studies, Page and her colleagues subjected rats either to abdominal surgery or physical stress, and then inoculated them with cancer cells. In the rats which had undergone surgery, the researchers observed a 200 to 500 percent increase in the incidence of lung tumor cells, an early indicator of metastasis, compared with those which had not received surgery.