Background: This prospective study evaluated the use of the K isozyme of lactate dehydrogenase (LDH-K) as a complementary tumor marker to carcinoembryonic antigen (CEA) in patients with colorectal adenocarcinoma.
Methods: In this series, 355 patients underwent potentially curative surgery for primary colorectal adenocarcinoma. A close surveillance program of follow-up revealed 108 patients (30%) who had a serum elevation in CEA and/or LDH-K.
Results: The patients were divided into three groups. Group 1 consisted of 43 patients with elevations in CEA alone. Twenty-seven of 43 patients (63%) had tumor at exploratory laparotomy; and 16 patients (37%) had no evidence of disease after a median follow-up of 74 months. Group 2 consisted of 33 patients with a serum elevation of LDH-K alone. In this group, 5 of 33 patients (15%) had recurrent disease with true elevations of LDH-K. In 28 patients (85%), there were falsely elevated levels of LDH-K with no evidence of disease. Group 3 consisted of 32 patients with elevations of both serum LDH-K and CEA. In this group, 17 of 32 patients (53%) had true elevations of CEA and LDH-K with tumor recurrence, and 15 patients (47%) had false elevations with no evidence of disease.
Conclusion: LDH-K did not complement CEA as a tumor marker for detecting recurrence in this group of patients with colorectal cancer.