The prognostic value of postoperative tumor marker conversion for gastric cancer

Preoperative positivity of serum tumor markers has been associated with poor long-term survival among patients with gastric cancer. However, there have been a considerable number of patients who have experienced a normalization of tumor markers (negative conversion) after curative treatment. This study aimed to evaluate the correlation between postoperative tumor marker conversion and survival after gastrectomy among gastric carcinoma patients.

We analyzed the clinical data of 129 patients who underwent curative gastrectomy with elevated preoperative carcinoembryonic antigen or carbohydrate antigen 19-9 between January 2009 and December 2013.

Positive tumor markers converted to negative markers 6 months after surgery in 91 patients (70.5%). The patients with a negative conversion of tumor markers had significantly better outcomes than those without negative conversion (overall survival [OS] 63.9 months vs. 41.1 months, P<0.001; disease-free survival [DFS] 59.3 months vs. 33.2 months, P<0.001). Multivariate analyses showed that tumor marker conversion and lymph node metastasis were independent predictors of OS and DFS. During follow-up, tumor markers became elevated again (positive reconversion) in 23 patients (25.3%), with a negative conversion of tumor markers at 6 months after gastrectomy. Among the patients with a positive reconversion of tumor markers, gastric cancer recurred in 18 patients (78.3%).

Negative tumor marker conversion after curative gastrectomy strongly predicts a better prognosis. Patients without negative tumor marker conversion and those with positive reconversion after normalization should be carefully monitored because of the high possibility of recurrence.