Carcinoembryonic antigen(CEA) is a routine marker employed for follow-up of colorectal tumors. We aimed to determine whether a CEA increase within the normal range can be linked to a risk of recurrence. From the period of 2006–2013 we selected 78 consecutive patients with colorectal cancer, who underwent curative surgery with or without neo-/adjuvant chemo- or radiotherapy and had proper follow-up procedures. For analyzing CEA fluctuation, we used the smallest value of the CEA during follow-up as the reference. With the aid of a Chi-squared test, we have chosen the value of 1.1 ng/mL for significant CEA fluctuation. A total of 43.6% of patients had fluctuations in CEA of at least 1.1 ng/mL, with or without increases above 5 ng/mL. From these, in 79.4% of patients, the increases in CEA were explained either by recurrence (44.1%), adjuvant chemotherapy (20.6%) or benign pathology (14.7%). In 23% of the recurrences, a CEA increase of at least 1.1 ng/mL, but below 5 ng/mL, preceded the clinical relapse by a median of 8 months. Our conclusion is that an increase in CEA levels by at least 1.1 ng/mL within the normal range after curative treatment for colorectal cancer may serve as an early indicator of relapse or could be associated with other pathological conditions.

Carcinoembriogenic antigen (CEA) is a routine marker for follow-up of colo-rectal cancers. We aimed to determine whether a CEA increase within the normal range can be linked to a recurrence risk. We included 78 consecutive patients with colo-rectal cancer, who underwent curative surgical treatment with or without chemo- or radiotherapy. As reference, we used the smallest value of the CEA during follow-up. A total of 34/78 patients (43.6%) had fluctuations of CEA of at least 1.1 ng/ml, with or without increases above 5 ng/ml. In 27/34 patients (79.4%) increases of CEA were explained either by recurrence (15/34 patients, 44.1%), adjuvant chemotherapy (7/34 patients, 20.6%) or benign pathology (5/34 patients, 14.7%). In 5 of 22 recurrences (23%) a CEA increase of at least 1.1 ng/ml, but below 5 ng/ml preceded the clinical relapse by a median of 8 months (range 3-22 months). The 4-year disease-free survival was 89% in patients with postoperative CEA 2.5 ng/ml. CEA increase by at least 1.1 ng/ml within the normal range, after curative treatment of colorectal cancer can be either an early sign of relapse or can be usually explained by other pathological processes.