High level of serum lactate dehydrogenase (LDH) is a well-known poor prognostic factor in patients with malignancies. However, there was no data on overall survival (OS) in cancer patients with serum LDH level > 1000 IU/L, and the prognostic value of the changes in LDH over time for OS had not been reported. Clinical data of 311 cancer patients with metastatic disease with serum LDH >1000 IU/L (four times upper limit of normal) admitted consecutively to a single center were reviewed in this retrospective study. LDH level ranged from 1002 to 8235 U/L with a mean of 1689 U/L. The median OS was 1.7 months (95 % CI: 1.4-2.0). About half of patients (n = 163, 52 %) died within 2 months with the median OS of 0.5 months (95 % CI: 0.3-0.7). Only 173 patients were indicated for salvage treatment. Fifty-one patients' serum LDH level decreased to normal at 2 months following chemotherapy; OS was significantly longer in these patients (22.6 months, 95 % CI: 10.9-34.3, p < 0.001) compared to those with persistently abnormal serum LDH at 2 months (4.0 months, 95 % CI: 3.4-4.6). The independent factors that increased the death risk were ECOG performance status 3-4 (HR: 2.05, 95 % CI: 1.42-2.97, p < 0.001), supportive care only (HR: 2.91, 95 % CI: 2.06-4.10, p < 0.001), and persistently abnormal serum LDH at 2 months (HR: 2.72, 95 % CI: 1.67-4.42, p < 0.001). In conclusion, serum LDH level > 1000 IU/L predicted a terminal stage in metastatic cancer patients. OS was significantly prolonged in patients indicated for effective palliative treatment and LDH level decreased to normal at 2 months.
Keywords: Lactate dehydrogenase; Metastatic cancer; Overall survival; Palliative care; Prognostic factor.