Prognostic impact of LDH and HCG levels in marker-positive seminomas.

Abstract

392 Background: The prognostic impact of LDH and HCG serum levels in marker positive metastatic seminoma patients is uncertain. This analysis evaluated the association between LDH and HCG levels with oncological outcomes in this patient population. Methods: Seminoma patients with elevated HCG levels were retrospectively analyzed. After stratification according to tumor marker levels pre- and post-orchiectomy, outcomes of subgroups were compared using log-rank test and cox-regression analysis. Study endpoints were cancer specific- (CSS) and recurrence-free survival (RFS). Results: In total, 429 HCG-positive metastatic seminoma patients (stage II n=291; stage III n=138) diagnosed between 1981 and 2018 were included. LDH + HCG levels ranged from 124 U/l to 8833 U/l (median: 619; IQR: 955) + 2 IU/l to 283,782 IU/l (median: 20; IQR: 63) pre- and from 107 U/l to 8650 U/l (median: 324; IQR: 481) + 0 IU/l to 36700 IU/l post-orchiectomy (median: 30; IQR: 121), respectively. Five-year CSS and RFS rates were 90% and 79%, respectively. Patients with LDH levels pre-orchiectomy <1.5 UNL (n=142) had a 5-year CSS (RFS) rate of 97% (88%), compared to 86% (81%) for ≥1.5 to 3 UNL (n=40), 83% (77%) for >3 to 5 UNL (n=44) and 83% (72%) for >5 UNL (n=44) (CSS p <0.001; RFS p=0.142). Concerning LDH levels post-orchiectomy this stratification was not significant but patients with LDH levels ≥3 UNL (n=77) displayed an impaired prognosis associated with a 5-year CSS (RFS) rate of 85% (79%) compared to 94% (82%) for levels <3 UNL (n=186) (CSS p=0.025; RFS p=0.447). Patients with HCG levels ≥2000 IU/l (n=17) pre- but not post-orchiectomy had a 5-year CSS (RFS) rate of 73% (60%) compared to 94% (79%) for patients with HCG levels <2000 IU/l (n=855) (CSS p=0.09; RFS p=0.04). In cox-regression analysis LDH ≥1.5 UNL (p=0.037; HR 3.32, CI95%1.08-10.26) and HCG levels ≥2000 IU/l (p=0.044; HR 3.69, 95%CI1.04-13.13) pre-orchiectomy were confirmed as prognostic factors for CSS. Conclusions: LDH levels inversely correlate with survival outcomes, suggesting ≥1.5 UNL pre- and ≥3 UNL post-orchiectomy as potential cut-off values for further risk assessment. Patients with extensive HCG elevations may represent an unfavorable subgroup concerning RFS and CSS, but only few patients were affected.