Objective: Intracranial giant cell tumors (GCTs) are extremely rare neoplasms with dismal survival and recurrence rates. The authors aimed to confirm independent adverse factors for progression-free survival (PFS) and to propose an optimal treatment algorithm.
Methods: The authors reviewed the clinical data of 43 cases of intracranial GCTs in their series. They also reviewed 90 cases of previously reported GCTs in the English language between 1982 and 2017 using Ovid MEDLINE, Embase, PubMed, and Cochrane databases with keywords of "giant cell tumor" or "osteoclastoma" and "skull," "skull base," "temporal," "frontal," "sphenoid," or "occipital." These prior publication data were processed and used according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Aforementioned risk factors for the authors' series and the pooled cases were evaluated in patients not lost to follow-up (m = 38 and n = 128, respectively).
Results: The authors' cohort included 28 males and 15 females with a mean age of 30.5 years. Gross-total resection (GTR) was achieved in 15 (34.9%) patients. Fifteen patients (39.5%) who did not undergo GTR received postoperative radiotherapy with a mean total dose of 54.7 ± 4.1 Gy. After a mean follow-up of 71.3 months, 12 (31.6%) patients experienced recurrence, and 4 (10.5%) died of disease. The actuarial 5-year PFS and overall survival (OS) were 68.6% and 90.0% in the authors' cohort, respectively. A multivariate Cox regression analysis verified that partial resection (HR 7.909, 95% CI 2.296-27.247, p = 0.001), no radiotherapy (HR 0.114, 95% CI 0.023-0.568, p = 0.008), and Ki-67 ≥ 10% (HR 7.816, 95% CI 1.584-38.575, p = 0.012) were independent adverse factors for PFS. Among the 90 cases in the literature, GTR was achieved in 49 (54.4%) cases. Radiotherapy was administered to 33 (36.7%) patients with a mean total dose of 47.1 ± 5.6 Gy. After a mean follow-up of 31.5 months, recurrence and death occurred in 17 (18.9%) and 5 (5.6%) cases, respectively. Among the pooled cases, the 5-year PFS and OS were 69.6% and 89.2%, respectively. A multivariate model demonstrated that partial resection (HR 4.792, 95% CI 2.909-7.893, p < 0.001) and no radiotherapy (HR 0.165, 95% CI 0.065-0.423, p < 0.001) were independent adverse factors for poor PFS.
Conclusions: GTR and radiotherapy were independent favorable factors for PFS of intracranial GCTs. Based on these findings, GTR alone or GTR plus radiotherapy was advocated as an optimal treatment; otherwise, partial resection plus radiotherapy with a dose ≥ 45 Gy, if tolerable, was a secondary alternative. Lack of randomized data of the study was stressed, and future studies with larger cohorts are necessary to verify these findings.Systematic review no.: CRD42018090878 (crd.york.ac.uk/PROSPERO/).
Keywords: EMA = epithelial membrane antigen; EMPT = estimated mean PFS time; GCRG = giant cell reparative granuloma; GCT = giant cell tumor; GKRS = Gamma Knife radiosurgery; GTR = gross-total resection; IMRT = intensity-modulated radiotherapy; KPS = Karnofsky Performance Scale; OS = overall survival; PFS = progression-free survival; PR = partial resection; STR = subtotal resection; TMJ = temporomandibular joint; bone giant cell tumor; intracranial; oncology; radiotherapy; treatment algorithm.