Rare Tumors: A Different Perspective on Oncology

Testicular and ovarian Juvenile granulosa cell tumors in children and adolescents: Analysis of 113 patients registered to the German Registry for Rare Pediatric Tumors (STEP)

BACKGROUND

In juvenile granulosa cell tumors (juvGCTs), impaired survival was reported after preoperative tumor rupture, peritoneal metastases, or high mitotic rate (≥20 mitoses per 10 high-power fields). Therefore, a risk stratification was developed to select patients for chemotherapy.

METHODS

Between 2001 and 2019, 89 female patients and 24 male patients were prospectively enrolled. Histopathologic classification was according to the World Health Organization classification, and staging was according to Children's Oncology Group and International Federation of Gynecology and Obstetrics classification.

RESULTS

Testicular juvGCTs were detected as scrotal swelling during infancy. No recurrences were reported after orchiectomy. Patients with ovarian juvGCTs presented at a median age of 9.8 years with abdominal discomfort, isosexual precocity, or amenorrhea. After tumor resection, two of 52 patients with stage IA disease, one of 14 with stage IC1 disease (intraoperative rupture), 13 of 18 with stage IC2 or IC3 disease (preoperative rupture), and all five patients with stage II/III disease received chemotherapy. Four recurrences with two deaths were reported. Three recurrent tumors were initially stage IA with a high mitotic rate, and one was a stage II tumor. No recurrences were observed among patients who had stage IC2/IC3 disease, who had unfavorable prognoses in historical cohorts. The 5-year event-free survival was 0.95 ± 0.03 (85 of 89 patients), and overall survival was 0.97 ± 0.02 (87 of 89 patients).

CONCLUSIONS

Testicular and ovarian juvGCTs are clinically distinct entities. Although testicular juvGCTs exclusively present during infancy and have an excellent prognosis, ovarian juvGCTs may arise at any age and constitute potentially aggressive tumors. Centralized reference diagnostics and the establishment of counseling structures for the treatment of patients with ovarian juvGCTs improved prognosis compared with historical groups. The mitotic rate and incomplete surgery were identified as important risk factors in addition to tumor stage and should be considered in the risk-stratification of therapy.

Facing the challenges of very rare tumors of pediatric age: The European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) background, goals, and achievements

It has become increasingly clear in recent years that we need to develop ad hoc strategies to combat very rare tumors (VRT) of pediatric age. In 2008, several schemes being run in different countries were pooled together to create the European Cooperative Study Group for Pediatric Rare Tumors (EXPeRT) project: a cooperative study group that aimed to promote research in the relatively uncharted territory of rare tumors of pediatric age. EXPeRT members were able to activate different levels of cooperation to achieve their goals, and to obtain dedicated funding by participating in EU-financed projects. Their experiences emphasize the merits of networking, seeking new partnerships, joining forces, and pooling resources to extend the reach of research efforts, and ultimately improve the quality of patient care. Between 2018 and 2021, the EXPeRT has been active in establishing the Pediatric Rare Tumors Network - European Registry (PARTNER). This project had the main purposes of building a European common registry of pediatric VRT, but also the major task of developing diagnostic and treatment guidelines for VRT (or at least part of them). These clinical recommendations are the subject of a series of papers on Pediatric Blood and Cancer.