The utility of lactate dehydrogenase in the follow-up of testicular germ cell tumours

Objectives To evaluate the utility of lactate dehydrogenase (LDH), a tumour marker that is frequently elevated at diagnosis and relapse of testicular germ cell tumours (TGCTs), in the follow-up of TGCTs for detecting tumour relapse, as it has role as a prognostic factor but its role in follow-up is less certain. Patients and methods We retrospectively reviewed 499 patients with TGCT who were followed from 1 January 2004 to 31 December 2005, with no clinical evidence of disease after a complete response to treatment or on surveillance for stage I disease. Results Of patients attending for follow-up or surveillance, in 26 of 1777 (1.4%) 'patient-visits' there was a high LDH level related to disease, and in 137 of 1777 (7.7%) such visits there was a high LDH from unrelated causes. Of the 499 patients who were followed, 15 relapsed; the LDH level was high in six of 15 who relapsed, with LDH being one of the first elevated markers in four and the only elevated marker in one (seminoma). Of the 449 patients, 41 (9.1%) had a persistent false-positive increase in LDH. The sensitivity of LDH was 40%, the specificity 90.5% and the positive predictive value 12.8% to detect relapse of disease during the follow-up of TGCTs. When the series of 116 relapsed patients from 1992 to 2005 was analysed, an increase in LDH facilitated the detection of relapse in 2% of non-seminomatous GCTs and 11% of seminomas, independent of other markers. Conclusion LDH has limited sensitivity, specificity and positive predictive value for detecting relapse of TGCT and false-positive increases are common. An elevated LDH level contributed to the detection in six of 15 relapses, suggesting that its value in the follow-up of TGCT might be useful if interpreted cautiously. High LDH levels during the follow-up might require repeat serial LDH estimates to confirm the elevation, and imaging to detect a relapse.