Background: Epidermal growth factor (EGF) stimulates tumor growth directly via tumor cell EGF receptors or indirectly via its proangiogenic effects. This study's purpose was to determine the impact of minimally invasive colorectal resection (MICR) on postoperative (postop) plasma EGF levels in the colorectal cancer (CRC) and benign disease settings and to see if preoperative (PreOp) EGF levels are altered in cancer patients.
Methods: MICR patients with benign pathology (n = 40) and CRC (n = 48) had blood samples taken PreOp and on postoperative days (POD) 1 and 3. In some patients, late samples were taken between POD7 and POD60; these were bundled into 7-day blocks and considered as single time points. EGF levels were determined by enzyme-linked immunosorbent assay (ELISA) and results were reported as mean ± SD after logarithmic transformation. The Student t test was used (p < 0.008 after Bonferroni correction).
Results: The cancer and benign groups were comparable except for age. The mean PreOp CRC plasma EGF level (122.9 ± 75.9 pg/ml) was significantly higher than that of the benign group (85.3 ± 38.5 pg/ml) (p = 0.015). The cancer group's EGF levels were significantly decreased on POD1 and POD3 and for the POD31-55 time point (mean EGF level = 63.1 ± 42.2 (n = 10). The benign group's POD3 and POD7-14 EGF levels were significantly lower than the PreOp level; later levels returned toward baseline. Small late sample size limited analysis.
Conclusion: Plasma EGF levels are significantly higher in cancer patients. MICR is associated with a significant decrease in EGF levels early postop in both cancer and benign settings. Unlike the benign group, EGF blood levels in cancer patients remain low during the second postop month. A larger study with more late samples is needed to verify these results. EGF may have value as a tumor marker.