Serum lactate dehydrogenase isoenzyme I and relapse in patients with nonseminomatous testicular germ cell tumors clinical stage I

Serum lactate dehydrogenase isoenzyme I catalytic concentration (S-LD-1) wa s measured at the time of orchiectomy in 104 patients with nonseminomatous testicular germ cell tumors (NSTGCT) clinical stage I who participated in a randomized study comparing surveillance after orchiectomy (group I) and ra diotherapy (group II). For 68 patients. S-LD-1 was measured in a serum samp le before or on the day of the orchiectomy. Twenty-seven patients (40%) had elevated S-LD-1: median 102 U/L (range 41-335). For the remaining 36 patie nt S-LD-1 was measured in a serum sample after orchiectomy: 8 of these pati ents (22%) had elevated S-LID-1. S-LD-1 was normalized shortly after surger y in most patients with a preorchiectomy elevated S-LD-1. Fifteen of the 68 patients relapsed: 9 out of 27 with an elevated S-LD-l and 6 out of 41 pat ients with normal S-LD-1 (p=0.13. Fisher's exact test). In group 1, those w ith a preoperatively elevated S-LD-I had a lower 8-years' relapse-free surv ival than those with a normal S-LD-I (40% vs. 80%, p = 0.003, log-rank test ). The role of S-LD-1 in the staging, prognostication and monitoring of pat ients with NSGCT clinical stage I should be further explored in a large, pr ospective study.