Clinicoradiological features and surgical outcomes of primary intracranial medulloepitheliomas: a single-center experience and pooled analysis of individual patient data.

OBJECTIVE

Medulloepithelioma (MEPL) is a rare, malignant primitive neuroectodermal tumor with dismal survival rates. The authors aimed to define independent risk factors for progression-free survival (PFS) and overall survival (OS) and to propose an optimal treatment protocol for MEPL.

METHODS

The authors reviewed the clinicoradiological data obtained in 12 patients with MEPL who underwent surgical treatment at their institution between January 2008 and June 2016. In addition, they reviewed 55 cases of MEPL published in the literature from January 1957 to July 2017. A pooled analysis of individual patient data of these 67 patients was performed to evaluate risk factors.

RESULTS

The authors' cohort included 5 males and 7 females with a mean age of 15.7 years. Gross-total resection (GTR) was achieved in 10 (83.3%) patients. Radiotherapy (mean total dose 42.8 Gy) and chemotherapy were administered to 7 and 4 patients, respectively. After a median follow-up of 21.7 months, 6 (50%) patients suffered recurrence and subsequently died, with median PFS and OS times of 5.5 and 13.9 months, respectively. Among the 55 patients in the literature, 13 (23.6%) patients received GTR, and 25 (49.0%) and 15 (29.4%) received radiotherapy (median total dose 53.2 Gy) and chemotherapy, respectively. After a median follow-up of 10.0 months, the recurrence and mortality rates were 69.7% (23/33) and 70.8% (34/48), respectively, and the median PFS was 6.0 months. Of the pooled cohort, the actuarial 5-year PFS and OS were 36.3% and 29.2%, respectively, and the estimated median survival time for PFS and OS were 12.8 and 15.2 months, respectively. A multivariate Cox model verified non-GTR (HR 5.537, p < 0.001) and no radiotherapy (HR 3.553, p = 0.008) as independent adverse factors for PFS. The 5-year PFS in patients with or without GTR was 63.8% and 6.3%, respectively, and in patients with or without radiotherapy was 42.7% and 23.1%, respectively. A multivariate model demonstrated non-GTR (HR 9.089, p < 0.001), no radiotherapy (HR 3.126, p = 0.004), and no chemotherapy (HR 3.621, p = 0.004) as independent adverse factors for poor OS. The 5-year OS in patients with GTR, radiotherapy, or chemotherapy was 72.1%, 44.0%, and 58.0%, respectively. In contrast, in patients without GTR, radiotherapy, or chemotherapy, the 5-year OS was 5.8%, 14.3%, and 15.8%, respectively. Overall, in patients receiving GTR plus chemoradiotherapy, the actuarial 5-year PFS and OS were both 87.5%.

CONCLUSIONS

MEPL is a rare neoplastic entity with a poor prognosis. There are no distinguishing radiological features apart from cystic degeneration. Via the pooled analysis, the authors identified independent adjustable factors associated with PFS and OS, from which they advocate for GTR plus chemoradiotherapy with a sufficient dose if tolerable as an optimal treatment to improve outcomes. Future studies with large cohorts will be necessary to verify our findings.