Search

Introduction: Angiogenesis is central to wound healing and tumor growth. Postoperative (postop) plasma from weeks 2 and 3 after minimally invasive colorectal resection (MICR) stimulates endothelial cell (EC) migration (MIG), invasion (INV), and proliferation (all vital to angiogenesis) compared with preoperative (preop) plasma results and may promote postop tumor growth. The purpose of this study was to determine whether plasma from open colorectal resection (OCR) patients has similar proangiogenic EC effects in vitro., Methods: OCR cancer patient plasma from institutional review board-approved banks was used; patients with preop and one postop sample from postoperative days (POD) 7-33 were eligible. Samples were bundled into 7- to 13-day periods and considered as single time points. In vitro cultures of human umbilical venous ECs were used for the EC proliferation (BPF, Branch Point Formation), INV, and MIG assays performed with preop, POD 7-13, POD 14-20, and POD 21-33 plasma. Data were analyzed by paired t test and were reported as mean ± standard deviation (significance, P < 0.05)., Results: Plasma from 53 cancer patients (25 rectal and 28 colon) was used. Because of limited postop samples, the number for each time point varies: POD 7-13, n = 30; POD 14-20, n = 26; and POD 21-33, n = 17. In vitro EC BPF was significantly greater at the POD 7-13 (P < 0.0001) and POD 14-20 (P < 0.0001) time points versus preop results. Significantly greater EC INV and MIG were noted on POD 7-13 and POD 14-20 versus the preop plasma results (P < 0.0001). In regards to POD 21-33, a significantly greater result was noted only for the INV assay versus preop., Conclusions: Plasma from weeks 2 and 3 after OCR stimulates in vitro EC BPF, INV, and MIG. A significant difference from preop baseline was noted only for the INV assay in week 4. The OCR and previous MICR results were largely similar. Tumor angiogenesis may be stimulated after OCR and MICR for 3 weeks. Further studies are warranted.

Introduction: Angiostatin and endostatin are endogenous inhibitors of angiogenesis with anticancer effects. After minimally invasive colorectal resection (MICR), blood levels of the proangiogenic factors vascular endothelial growth factor (VEGF) and angiopoetin 2 (Ang-2) are elevated for 2-4 weeks. Also, postoperative human plasma from weeks 2 and 3 after MICR has been shown to stimulate endothelial cell proliferation and migration, which are critical to angiogenesis. This proangiogenic state may stimulate tumor growth early after MICR. Surgery's impact on angiostatin and endostatin is unknown. This study's purpose is to determine perioperative plasma levels of these two proteins in colorectal cancer (CRC) patients undergoing MICR., Methods: Endostatin levels were assessed in 34 CRC patients and angiostatin levels in 30 CRC patients. Blood samples were taken preoperatively and on postoperative day (POD) 1 and 3 in all patients; in a subset, samples were taken between POD 7 and 20. The late samples were bundled into 7-day blocks (POD 7-13, POD 14-20) and considered as single time points. Angiostatin and endostatin plasma levels were determined via enzyme-linked immunosorbent assay (ELISA) in duplicate. Wilcoxon signed-rank test and Student's t test were used to analyze endostatin and angiostatin data, respectively. Significance was set at P<0.0125 (after Bonferroni correction)., Results: There was a significant decrease in median plasma endostatin levels on POD 1, which returned to the preoperative level by POD 3. There was no significant difference between pre- and postoperative plasma angiostatin levels., Conclusions: MICR has a very transient impact on plasma levels of endostatin and no impact on angiostatin during the first 21 days following surgery. Thus, angiostatin and endostatin do not likely contribute to or inhibit the persistent proangiogenic changes noted after MICR.

Background: Angiopoetin- (Ang-) 1 inhibits and Ang-2 promotes VEGF-mediated angiogenesis via binding to endothelial cell-bound Tie-2 receptor (Tie-2). After minimally invasive colorectal resection (MICR), Ang-1 levels decrease and Ang-2 levels increase, which may stimulate angiogenesis in wounds and residual tumor foci. Soluble Tie-2 (sTie-2) modulates the effects of free Ang-1 and Ang-2 by binding to them. This study assessed perioperative MICR plasma sTie-2 levels., Methods: Blood samples were taken preoperatively (PreOp) and on postoperative days (POD) 1 and 3 from 50 cancer and 53 benign disease MICR patients. In a subgroup, a fourth sample was taken between POD7 and POD13 and bundled as a single time point. sTie-2 levels (ng/ml) were determined via ELISA. The mean and SD were determined at each time point. The t test used for analysis., Results: PreOp plasma sTie-2 levels were significantly higher in the benign group (27.6 ± 10.2) than in the cancer group (22.9 ± 7.9). A significant drop from PreOp occurred in sTie-2 levels in the cancer group on POD1 (20.0 ± 7.4) and POD3 (21.0 ± 6.6) and in the benign group on POD1 (24.8 ± 9.1). The benign group's POD3 and the cancer group's POD7-13 sTie-2 levels were statistically similar to the PreOp levels while the benign group's POD7-13 level was significantly higher., Conclusion: PreOp sTie-2 levels were significantly lower in cancer patients. MICR is associated with a significant short-lived decrease in plasma sTie-2 levels in cancer patients on POD1 and 3, which may briefly inhibit VEGF-mediated angiogenesis. The benign group's early results were similar.

Background: This study aimed to determine the diagnostic yield of colonoscopy 1 year after colorectal cancer (CRC) resection based on whether the index colonoscopy was performed by the operating surgeon., Methods: All patients undergoing surgery for colorectal cancer by two colon and rectal surgeons at a university hospital from 1991 to 2005 were identified from the tumor registry. Those patients with a complete preoperative colonoscopy by any physician and a 1-year follow-up examination by the operating surgeon were selected for the study population. Family history of colorectal cancer, tumor location, endoscopist, presence of synchronous neoplasms, and findings of 1-year colonoscopy were recorded. Fisher's exact test was used to compare the probability of finding any adenoma, advanced adenoma, or invasive cancer based on the index endoscopist., Results: Of the 719 patients who underwent resection during the study period, 432 met the inclusion criteria. The index colonoscopy for 117 of these patients (27.1%) was performed by one of the two surgeons. Overall, 10 patients (2.3%) had a "new" cancer diagnosed at 1 year, and 1 patient (0.2%) had a local recurrence. Patients whose index colonoscopy was performed by their operating surgeon appeared less likely to have an advanced lesion found at 1 year (5.1% vs 11.4%; p = 0.06). The index colonoscopy for 9 of the 10 of cancers found at 1 year was not performed by the operating surgeon., Conclusions: Colonoscopy 1 year after CRC resection is clearly justified. An index colonoscopy by the operating surgeon eliminates a "handoff" and may diminish the incidence of high-risk lesions at 1 year.