P2D326: Risk Factors for Recurrence of Sacrococcygeal Teratoma

Background: Surgery is the primary treatment for infants and young children with sacrococcygeal teratoma (SCT). Recurrence after surgical resection remains a stubborn problem and is difficult to predict. Malignancy and positive margins are well-known risk factors, but why some mature tumors are more likely to recur is less clear. Furthermore, an aggressive surgical approach for every tumor in such a sensitive anatomic location may result in serious long-term functional or cosmetic sequelae. In attempting to define risk factors for recurrence, we hypothesized that tumors with a solid component or microscopic deposits of malignant elements (yolk sac tumor, YST), might be more likely to recur after surgical resection.

Methods: We reviewed SCT resections at our institution from 2011-2021 and analyzed demographics, medical therapy, tumor characteristics, recurrence, and mortality. Multivariate logistic regression was performed for all variables.

Results: We identified 96 patients with SCT, 63.5% of whom were female (p=0.008). Average age at surgery was 0.92 years. On pathology, 59 had mature histology (61.5%), 16 immature (16.7%), and 21 YST (21.9%). After surgery, 16 patients (16.7%) developed local or metastatic recurrence at an average time of 0.82 +/- 0.62 years, which was detected initially by a rising AFP (62.5%), surveillance MRI (18.75%), mass on physical exam (12.5%), or constipation (6.25%). Among all patients, factors associated with recurrence included YST, positive margins, and the presence of a solid tumor component. Two patients died (2.1%), both of whom had initially presented with metastatic disease. Of the 59 with mature histology, 50 demonstrated entirely mature teratoma, while 9 also had microscopic foci of YST. Of this subset, microscopic YST was a significant risk factor for recurrence (44% vs 6%, OR 70.5 [4.3 – 6291], p = 0.01).

Conclusion: Among all patients with SCT, histology, tumor morphology, and positive margins are significant risk factors for tumor recurrence after initial resection. For patients with close margins, the presence of solid tumor may help determine the aggressiveness of resection. Patients whose mature tumors have foci of microscopic YST are more likely to have a recurrence and therefore might benefit from closer post-operative surveillance.