Association of serum lactate dehydrogenase (LDH) isozyme with prognosis of patients with metastatic clear cell renal cell carcinoma (mCRCC).

Abstract

709 Background: LDH isozyme is a tetramer of two subunits, H chain and M chain, and is present in all living tissue. Five types of molecular forms characterize the LDH pattern, and tumor tissues relatively consist LDH-4 and LDH-5, composed with a high ratio of the M chain, compared to normal tissues. This study analyzed the association between LDH isozyme and prognosis of mCRCC after nephrectomy. Methods: Clinical records of mCRCC patients those who were initially diagnosed M0 disease at Nippon Medical School between 2012 and 2016 were retrospectively reviewed. LDH isozyme values before operation and at time of metastasis were checked. Isozyme patterns were classified into 6 types, LDH 1-5 dominant and common type, according to the most composed molecular form. Results: Out of 38 patients, 33 patients (87%) were male, 5 patients (13%) were female. Median age was 65 years old (36-87). pT1 was seen in 3 cases, pT2 in 4, pT3 in 27, and pT4 in 4. Pathological grade 2 were 9 cases, G3 in 21, and G4 in 8. As for the IMDC risk, favourable was 2 cases (5%), intermediate in 26 (68%) and poor in 10 (26%). Median LDH was 163 IU/L (113-317), and isozyme dominant pattern were as follows: LDH-2 in 9 cases (24%), LDH-3 in 6 (16%), LDH-4 in 4, LDH-5 in 11. 8 cases were common type, and no cases showed LDH-1 dominant. Median time from surgery to recurrence was 10 months (1-104), median follow-up period after recurrence was 18 months (4-72). 16 deaths occurred. No significant correlation was seen between pre-operative LDH isozyme pattern and pathological grade or pT stage. Pre-operative LDH isozyme did not correlate with the time to recurrence (p=0.7420). The median OS for LDH-4 dominant at the time of metastasis was 10.9 months, significantly shorter than other isozyme types (P=0.0134). Conclusions: LDH-4 dominant isozyme pattern at the time of recurrence has a short OS, proposing as a prognostic predictor in mRCC.