BOB Ped Surg 2023 - Lieke Josephine Van Heurn, EUPSA - Presentation

Hello everyone. My name is Lieke van de Hurk from the Amsterdam University Medical Center. Risk of malignant transformation and tumor recurrence in Sacrococcygeal Teratoma: results of the SCCT study. Sacrococcygeal Teratoma or SCCT is the most common germ cell tumor in neonates with an estimated instance of one per 14,000 to 35,000 live births. The likelihood of malignant transformation increases with age, with malignancy rates up to 70% if SCD is diagnosed at the age of one year. Furthermore, recurrent SCCT can be found after primary resection. Most studied series are relatively small due to the rarity of the disease and conclusions regarding malignant transformation and therefore optimal time for surgical resection remain difficult to draw. Therefore, we aim to assess the risk of malignant transformation of SCCT at primary resection and risk of recurrence with its risk factors after resection in a large cohort of SCCT patients. With the help of the Eupsen Network office, centers all over the world were contacted for participation in the ACT study. All study documents were translated in multiple languages, including French, Spanish, Russian and English. Each participating center had an investigator on site. The onsite investigator collected and anonymized the patient data. Anonymous data was then collected with the help of Custer. This led to a fully anonymized database. More than 150 centers from 65 countries participated in the study. Data was collected for patients treated for SCCT between 1980 and 2020. Data for both patients treated for SCCT and for patients with SCCT associated with Curarino syndrome were collected. Data of patients where SCCT was associated with Curarino syndrome was not analyzed in this part of the study. The reason for the exclusion of Curarino patients in this part of the study is that it is unknown whether SCCT associated with Curarino has the same risk of malignant transformation as SCCT. This map shows the 65 countries participating in the SCCT study. From Europe, almost all countries participated in the study. As you can see, also Ukraine, Belarus and Russia participated in the study. Together, all participating centers included 3,614 patients with SCCT. For this part of the study, the 205 patients with Curarino syndrome were excluded and the remaining 3,409 SCCT patients were included in analysis. Most included children came from high and higher middle income countries. For income country, the World Bank classification was used. However, also children from low middle income countries such as Ivory Coast, the Philippines, Nigeria, and Cameroon were included. Furthermore, low income countries including Ethiopia and Syria also participated in the study. Probability of malignancy found at primary resection is shown in this graph. During the first six years of life, the probability of malignant transformation increases strongly. After six years of age, the probability remains stable at 60%. After six years of age, almost no malignancies have been found. Furthermore, malignancy can occur after primary resection during follow up. Malignancy-free survival was defined as children with malignancy at primary resection or malignant recurrence. Also children who died due to malignant disease or due to treatment received for malignancy disease were defined as malignancy during follow-up. Malignancy-free survival stabilized at the age of five year with a malignancy-free survival rate of 81%. However, late malignancies up to 15 years of age have been found. Most recurrences were found four year after initial resection. Probability of recurrence free survival was 85% four years after initial resection. However, incidental late recurrences up to 20 years after primary resection have been found in this study. Altman type two and three were significant risk factors for recurrent SCCT in our analysis. Both risk factors remain significant in multivariate analysis. The histology of the primary tumor was also a risk factor for recurrence, especially with malignant histology of the primary tumor increases the risk of recurrent SCCT with an odd ratio of 4.7. Income country was no risk risk factor for recurrent SCCT. We showed that malignant transformation increases strongly the first years of life. However, after six years of age, the risk of malignant transformation becomes very small. Furthermore, recurrent SCCT is mostly found four years after primary resection. However, late recurrences can occur. Lastly, the SCCT study shows that international collaboration for rare diseases is possible and that with the help of these international collaborations conclusions for rare diseases such as SCCT can be drawn. Thank you for your attention.