Introduction: It has been demonstrated that colorectal resection, both open and laparoscopic, for both benign and malignant indications is associated with significantly increased plasma VEGF levels early after surgery. This increase is likely related to the surgical wounds. Soluble VEGF Receptor 1 (sVEGFR1) is an endogenous VEGF inhibitor that binds VEGF in the bloodstream and prevents it from binding to endothelial cell bound VEGFR1 or VEGFR2. The impact of surgery on plasma levels of sVEGFR1 is unknown. The purpose of this study was to assess sVEGFR1 and VEGF levels before and after minimally invasive colorectal resection (MIR) for benign indications.
Methods: Plasma samples from patients with benign colorectal conditions undergoing MIS were obtained preoperatively (PO) and on postoperative days (POD) 1 and 3. Clinical, operative and postoperative data was also collected prospectively for all patients. Both VEGF and sVEGFR1 levels in the plasma were determined via commercially available ELISA kits in duplicate. The data was analyzed with Wilcox's Paired Test (significance, p < 0.05).
Results: A total of 33 patients were studied (mean age 57 yrs; male:female ratio, 18/15). The surgical method used was laparoscopic in 67% (mean incision 5.0 cm) and hand-assisted in 33% (mean incision 9.0 cm). The mean operative time was 222 minutes. The breakdown of resections was: sigmoid, 60%; right, 33%, other 7%. The indications were: diverticulitis, 58%; benign neoplasm, 30%; and other, 12%. The mean plasma sVEGFR1 levels were significantly increased on POD1 (165 +/-249 pg/ml) and on POD3 (168 +/-115 pg/ml) when compared to the preop result (82.8 +/-66 pg/ml, p<0.004 for both comparisons). Although the mean plasma VEGF level was increased on POD3 (143 +/-88 pg/ml) when compared to the preop result (116 +/-110 pg/ml) the difference was not statistically significant (p=0.079); the POD1 mean level was 95 +/-89 pg/ml.
Conclusion: MIS colorectal resection is associated with significantly increased plasma sVEGFR1 levels early after surgery for benign conditions. This elevation may serve to diminish the systemic impact of the increased plasma levels of VEGF noted previously in the early post-surgery time frame. The mechanism by which sVEGFR1 levels are increased after surgery is unknown. sVEGFR1 levels after cancer resection merit study since increased VEGF levels after surgery in that setting might stimulate the growth of residual tumor cells.