Minimally Invasive Surgery May Result in Lower Peak Levels of Circulating Vascular Endothelial Growth Factor

BACKGROUND: Angiogenesis is felt to be a factor in the establishment and progression of cancer and cancer metastasis. Vascular endothelial growth factor (VEGF) is one of the most powerful stimulants of tumor angiogenesis identified. VEGF levels can be affected by physiologic stimuli and measured systemically. METHODS: Circulating VEGF levels were measured immediately before and after laparoscopic colon surgery in 10 unselected sequential patients with a diagnosis requiring surgical intervention for colon pathology. RESULTS: Preoperative VEGF ranged from 31.3 pcg/cc to 187 pcg/cc. Postoperative VEGF ranged from 45 pcg/cc to 2228 pcg/cc. Factors of age, weight, diagnosis, length of cumulative skin incisions, and the receipt of preoperative blood products were considered. Data were compared by t test and regression analysis. Although several patients showed variability, some pronounced, in their pre- and postoperative levels, no 1 factor reached statistical significance as the cause of this variability. Utilizing regression analysis, however, considering only those patients in whom a diagnosis of cancer existed and who received blood products, the length of the incision alone accounted for an R(2) change of 0.471. That is, in this subset of patients, incision size alone accounted for almost half of the variability in VEGF. CONCLUSIONS: The data suggest a possible link between incision size in colon surgery and levels of VEGF. The sample size was insufficient for statistical significance. The study also does not answer whether a systemic release of VEGF at the time of surgery adversely affects the clinical outcome in cases of colon cancer. The data do warrant further investigation with a larger sample size and clinical follow-up.