Metastatic germ cell tumors of the testis (GCTs) are risk-stratified according to the International Germ Cell Cancer Collaborative Group (IGCCCG) classification system. This risk classification is based on anatomical risk factors as well as tumor marker levels of AFP, HCG, and LDH assessed pre-chemotherapy after orchiectomy treatment. An incorrect classification is possible when pre-orchiectomy marker levels are used, possibly resulting in over- or undertreatment of patients. The aim was to investigate the potential frequency and clinical relevance of incorrect risk stratification using pre-orchiectomy tumor marker levels.
A multicenter registry analysis, including patients with metastasized nonseminomatous GCT (NSGCT), was conducted by investigators of the German Testicular Cancer Study Group (GTCSG). Based on the marker levels at different timepoints, IGCCCG risk groups were calculated. The agreement was tested using Cohen\'s kappa.
A total of 672 of 1910 (35%) patients were diagnosed with metastatic NSGCTs, and 523 (78%) had sufficient data for 224 follow-up data points. By using pre-orchiectomy tumor marker levels, 106 patients (20%) would have been incorrectly classified. Seventy-two patients (14%) were classified into a higher risk category, and 34 patients (7%) were classified into a lower risk category. Cohen\'s kappa was 0.69 (p < 0.001), showing a strong agreement between the use of both marker timepoints. The treatment of misclassified patients would have resulted in an overtreatment of 72 patients or undertreatment of 34 patients.
The use of pre-orchiectomy tumor marker levels may lead to an incorrect risk classification and might subsequently lead to under- or overtreatment of patients.

BACKGROUND: The prognostic classification system of the International Germ Cell Cancer Cooperative Group (IGCCCG) for testicular germ cell tumors is based on the histological subtype, location of the primary tumor, extent of metastatic spread and prechemotherapy tumor marker serum concentrations.
OBJECTIVE: In this study, we aim to identify whether the use of preorchiectomy instead of prechemotherapy tumor marker serum concentration has an impact on IGCCCG risk group assignment.
METHODS: We performed a retrospective analysis including 135 patients with metastasized testicular germ cell tumors. Analysis of the clinical information with a focus on the tumor marker serum concentration preorchiectomy and prechemotherapy was performed, thus leading to the grouping of patients according to IGCCCG risk group assignment.
RESULTS: Using preorchiectomy instead of prechemotherapy tumor markers led to an incorrect IGCCCG risk group classification in 8% (11/135) of all patients, and consequently to a non-guideline concordant treatment. Up-staging was observed in 8 of 11 patients, representing 6% (8/135) of the total patient cohort. Three of the 11 misclassified patients showed a down-staging and thus describe 2% (3/135) of the total patient cohort.
CONCLUSIONS: Using preorchiectomy tumor markers instead of prechemotherapy serum concentration might lead to an incorrect IGCCCG risk group assignment as well as non-guideline concordant treatment. Consequently, prechemotherapy tumor marker serum concentration should be applied for guideline concordant staging of patients.
UNASSIGNED: HINTERGRUND: Das Klassifikationssystem zur Prognoseeinschätzung der International Germ Cell Cancer Cooperative Group (IGCCCG) für testikuläre Keimzelltumoren basiert auf dem histologischen Subtyp, der Lokalisation des Primärtumors und der Metastasen sowie der Serumkonzentrationen der Tumormarker vor Chemotherapie.
UNASSIGNED: Ziel der Arbeit war die Evaluation des Einflusses der Verwendung der Tumormarkerserumkonzentrationen vor Ablatio testis im Vergleich zu denen vor Chemotherapie im Hinblick auf die Eingruppierung entsprechend der IGCCCG-Klassifikation.
UNASSIGNED: Wir führen eine retrospektive Datenanalyse an 135 Patienten mit metastasiertem testikulärem Keimzelltumor durch, die eine Primärtherapie mit einer Chemotherapie erhalten haben. Es erfolgte die Analyse von klinischen Parametern mit Fokus auf der Tumormarkerserumkonzentration vor Ablatio testis und vor Chemotherapie, die zur Eingruppierung in eine Prognosegruppe entsprechend der IGCCCG-Klassifikation führten.
UNASSIGNED: Die Verwendung der Tumormarkerserumkonzentrationen zur Berechnung der IGCCCG-Klassifikation vor der Ablatio testis im Vergleich zu denen vor Chemotherapie führte bei 8 % (11/135) aller Patienten zu einer veränderten Prognosegruppe sowie daraus folgend nicht-leitliniengerechten Therapieschemata. Es zeigt sich ein „up-staging“ bei 8 der 11 Patienten und somit 6 % (8/135) der gesamten Patientenkohorte, d. h. die Serumkonzentrationen der Tumormarker sind nach Ablatio bis zum Beginn der Chemotherapie abgefallen. Bei 3 der 11 Patienten bzw. 2 % (3/135) der gesamten Patientenkohorte, kam es zu einem „down-staging“, d. h. die Tumormarker sind bis zum Beginn der Chemotherapie angestiegen.
UNASSIGNED: Die Verwendung der Tumormarkerserumkonzentrationen vor Ablatio testis im Vergleich zu denen vor Chemotherapie kann zu einer signifikanten IGCCCG-Fehlklassifikation und somit inkorrekter Therapie führen. Für ein leitlinienkonformes „staging“ der Patienten sollten folglich die Tumormarker vor der Chemotherapie verwendet werden.