MATURE AND IMMATURE TERATOMA: RESULTS OF THE FIRST PEDIATRIC ITALIAN STUDY ITALIAN

Abstract Teratoma is the most common germ cell tumour in childhood; mature (MT) and immature teratomas (IT) are benign tumours, but if they recur, they can be in some cases malignant. The aim of this paper is to evaluate Italian patients with MT and IT enrolled from 1991 to 2001, in a prospective multicentric study. One hundred and eighty-three patients, observed in 15 Italian Centers of Paediatric Oncology and three Paediatric Surgical Units were enrolled. Clinical data, treatment and results were all analysed. Initial evaluation and subsequent follow up included clinical examination, tumour markers and imaging procedures. Surgical resection was recommended for all the tumours. Histology was centrally reviewed and IT was classified as grading 1-3. Chemotherapy (CT) with Vinblastine, D: -actinomycin and cyclophosphamide was indicated for extra-testicular IT grade 2 or 3. MT was diagnosed in 127 patients (93 F and 34 M, age 1-192 months, median 24): 58 patients had gonadic tumour (23 testicular, 35 ovaric), 69 extragonadic (45 sacrococcygeal, 11 mediastinic, 7 retroperitoneal, 6 in other sites). A complete resection was performed in 117 patients, a partial resection in eight patients and biopsy in one. IT was diagnosed in 56 patients (34 F, 22 M, age 1-168 months, median 7). The T grading was 1 in 14 cases, 2 in 26, 3 in 16; 28 had gonadic T (17 ovary, 11 testis), 28 extragonadic (sacrococcygeal 19, mediastinic 3, retroperitoneal 2, other sites 4). CT was administered in eight patients; 15/182 patients relapsed (1 in a metastatic site) and in 5/15 the relapse showed malignant histology. Seven MT (5.5%) relapsed (five sacrococcygeal, one retroperitoneal, one mediastinic): surgery at diagnosis had been complete in five and with residual in two; the relapse was malignant in two patients with sacrococcygeal (sc) tumours, who had a complete resection and a partial resection respectively. Eight IT (14.2%) relapsed (four ovary, three sc, one retroperitoneal). The initial surgical resection had been complete in one, with residual in six, and a biopsy had been performed in one. A malignant recurrence occurred in two patients with sc tumours (after partial resection in one and after biopsy + CT in one) and in one patient with ovarian IT after a partial resection. All the patients underwent surgical excision of the recurred mass; CT according to Protocol for Malignant GCT was administered to those who had malignant recurrence; 122/126 patients with MT and 53/56 with IT are alive without disease with a follow up of 8-144 months (median 56). Two patients with malignant relapse (one with sc MT, one with sc IT) died because of the progression of the disease. Another two died due to severe malformations (one MT, one IT) and three were lost to follow up (two MT, one IT). The overall survival (OS) at 10 years is 98% (95% CI 93.9-99.4); the event free survival (EFS) is 90.4% (95 CI 84.8-94.0). At Cox analysis no significant difference in EFS was found regarding age and site of the primary tumour, while females (P = 0.011), patients with grade 1-3 histology (P = 0.025) and patients with incomplete resection appeared at higher risk of death or relapse (P < 0.001), with a seven, three and eightfold increase in risk, respectively. Our data showed that incomplete resection and female gender are important risk factors for relapse or death, more so than IT histology. The number of patients treated with CT is not sufficient to evaluate the efficacy of CT in avoiding malignant relapse.