Chemotherapy-induced transient CEA and CA19–9 surges in patients with metastatic or recurrent gastric cancer

Abstract

15603 Background: A rising of carcinoembryonic antigen (CEA) or carbohydrate antigen 19–9 (CA19–9) after chemotherapy is generally considered as tumor progression in patients with solid tumors. However, a transient elevation of CEA has been observed despite objective responses in metastatic colorectal or breast cancer patients receiving chemotherapy. This transient CEA surge phenomenon has not been previously described in patients with metastatic or recurrent gastric cancer (MRGC) and CA19–9 surge phenomenon has never been reported in solid tumor patients. Thus this study was performed to investigate the incidence of CEA and CA19–9 surges in MRGC patients and their implications on clinical outcome. Methods: Among 177 MRGC patients who received palliative chemotherapy at Seoul National University Bundang Hospital from January 2005 to July 2007, 51 and 40 patients had evaluable data for CEA or CA19–9 surges, respectively, and thus were included in this study. Both CEA and CA 19–9 surges were defined as a > 20% increase in these tumor markers from baseline (within 2 weeks from initial treatment) that is followed by a >20% drop in subsequent tumor marker levels compared to baseline. Results: Of 51 patients who were evaluable for CEA surges, 9 patients (17.6%) had documented CEA surges. The median time to CEA peak and the median duration of CEA surge were 2.8 weeks (range: 1.7∼7.0 weeks) and 9.1 weeks (range: 7.6∼21.0 weeks), respectively. Of 40 evaluable patients for CA19–9 surge, 7 patients (17.5%) had documented CA19–9 surge. The median time to CA19–9 peak and the median duration of CA19–9 surge were 2.3 weeks (range: 1.9∼6.0 weeks) and 7.1 weeks (range: 4.3∼16.1 weeks). All patients with CEA or CA19–9 surges had radiographic evidence of benefit (radiological response or stable disease) from chemotherapy. Conclusions: CEA or CA19–9 surges can be observed in MRGC patients receiving chemotherapy. All patients with these surge phenomenons had clinical benefits from chemotherapy. An initial rise in CEA or CA19–9 levels after initiation of chemotherapy should not be used as an indicator of progressive disease. No significant financial relationships to disclose.