“Letting the Air In” Can Set the Stage for Tumor Recurrences

Surgery is the single most effective therapy for patients with solid tumors. However, up to half of the patients who receive surgical resection will relapse from their cancer. Despite the significant benefit from surgery, there is a growing body of evidence that suggests that surgery may also contribute to tumor recurrence. The evidence supporting this claim can be divided into immunologic and non-immunologic mechanisms. The non-immunologic mechanisms associated with surgery include direct seeding through tissue manipulation, pressure activation of malignant cells, the release of angiogenic factors, and an increase in circulating growth factors. Surgery also has dramatic implications for the immune system; these include the suppression of cell-mediated immunity, the activation of the neuroendocrine response, and anesthesia related immunosuppression. The factors associated with post-surgical tumor recurrence are complex; nevertheless, a better understanding of these mechanisms provides an opportunity to develop therapeutic interventions that can lower the recurrence rate in patients with solid tumors.