Patients and methods: According to previous literature incomplete tumor resection, coccygeal or ovarian primary site and immaturity are known risk factors for relapse in teratoma. To establish a risk score points are allocated for resection, primary site and histology in the following manner and added: incomplete resection 4 points, primary site coccyx 3 points, ovary 2 points, other site 1 point, histological grading 0-3 points. This score system is evaluated on 270 extracranial non-testicular teratoma cases collected between 1982 and 1995 in the MAKEI cooperative treatment protocols of the German Society of Pediatric Oncology and Hematology. Treatment was resection alone (230 patients) or resection followed by postoperative adjuvant chemotherapy (40 patients).
Results: Patients treated with surgery alone: 28/230 (12%) patients relapsed, 14/230 (6%) patients showed highly malignant histology (mostly yolk sac tumor) in relapse. Mortality in case of relapse was 6/28 (21%). Patients scoring > or = 6 points (n = 45) had a relapse rate of 21/45 (47%) resulting in a 23%-mortality (5/21). Patients scoring < 6 points (n = 185) had a 4%-relapse risk (8/185) resulting in 13%-mortality (1/8) (p < 0.01). Patients treated with surgery and adjuvant chemotherapy: 7/40 patients (18%) suffered a relapse, none of them showing malignant histology. Mortality rate in case of relapse was 3/7 (43%). Patients scoring > or = 6 points initially treated with adjuvant chemotherapy (n = 18) had a relapse rate of 7/18 (39%), compared to patients scoring < 6 points (n = 22), in whom no relapses occurred (p < 0.01). There were no highly malignant relapses in the group treated with adjuvant chemotherapy. Regardless of the scored points the difference in highly malignant relapse histology comparing the group treated with surgery and adjuvant chemotherapy to the group treated with surgery was statistically significant (p = 0.02).
Conclusion: The risk score system marks a high risk group including 63/270 (23%) of all evaluated extracranial non-testicular teratoma cases (scoring > or = 6 points). In this group 28/35 (80%) of relapses and 8/9 (89%) of tumor deaths occurred. For this high risk group a randomized trial will be suggested to evaluate the effect of adjuvant chemotherapy on the rate of malignant relapses. It should also be investigated, if adjuvant chemotherapy will influence relapse rate and mortality.