Evaluation of epidermal growth factor receptor serum levels and their association with clinicopathological characteristics in patients with colorectal cancer.

Colorectal cancer (CRC) is a major public health concern and one of the leading causes of cancer-related mortality worldwide. The aim of the present study was to determine the serum epidermal growth factor receptor (sEGFR) levels in healthy volunteers and patients with CRC, to determine the association between tumor marker levels and clinicopathological findings, and investigate its prognostic value. A total of 140 patients with CRC were enrolled in the present study. Pre-treatment sEGFR levels were determined using ELISA. A total of 40 age- and sex-matched healthy controls were included in the analysis. The median age of patients was 60 years (range, 24-84 years); the majority of the tumor localization was to the colon (n=81, 58%). The median follow-up time was 14 months, while 43 (31%) patients experienced disease progression and 31 (22%) succumbed to the disease. A total of 81 patients (58%) were in the early stages of disease (stage II and III), and 42% of the patients had stage IV disease. The estimated 2-year overall and 1-year progression-free survival rates for the whole patient group were 70% [95% confidence interval (CI): 58.8-81.2] and 26.2% (95% CI: 12.9-39.5), respectively. The number of patients who received neoadjuvant treatment was 37. Of the patients who were administered palliative treatment, 24 received oxaliplatin, whereas 22 received irinotecan and 9 received fluorouracil/capecitabine. A total of 36 and 15 of the patients who received targeted therapy were administered bevacizumab and cetuximab, respectively. Of the 55 patients with metastatic disease who received palliative chemotherapy (CTx), 31% were CTx-responsive. The baseline median sEGFR levels were significantly higher in patients with CRC compared with the healthy control group (P=0.002). In addition, established clinical variables, including no surgical resection, metastatic stage, higher pathological tumor stage, poorer regression score (3-4) and higher lactate dehydrogenase levels, were found to be associated with higher sEGFR levels (P=0.03, P=0.009, P=0.05, P=0.05 and P=0.05, respectively). The results of the present study did not reveal statistically significant associations between sEGFR concentrations and overall and progression-free survival rates. In conclusion, sEGFR concentrations may be diagnostic markers in patients with CRC; however, their predictive and prognostic values were not determined.