THE COMPARATIVE RESULTS OF ADJUVANT CHEMOTHERAPY WITH HYDROXYUREA VERSUS RADIOTHERAPY AFTER INCOMPLETE RESECTION OF ATYPICAL MENINGIOMAS

Atypical meningiomas classified as WHO grade II are more locally aggressive and demonstrate more rapid tumor progression than benign meningiomas of WHO grade I. Immediate adjuvant treatment after surgery for the atypical subtype is still under debate. Therefore, we investigated the clinical results of adjuvant chemotherapy with hydroxyurea versus radiotherapy after incomplete resection of atypical meningiomas. The authors retrospectively reviewed the medical records of 412 patients with meningiomas diagnosed in the period from January 2000 to December 2014 at our hospital. Clinical and radiological data included extent of surgery, use of adjuvant therapy, duration of follow-up, and progression. In terms of the extent of surgical resection, incomplete resection was defined as Simpson Grade II–V. The progression rate and time to progression were assessed using Kaplan-Meier analysis. Of the 84 atypical meningiomas eligible for analysis, 55 (65.5%) patients underwent incomplete resection. Among them, 24 (43.6%) were treated with adjuvant hydroxyurea (group A), and 20 (36.4%) with postoperative radiotherapy (group B), and 11 (20.0%) underwent conservative treatment after surgery (group C). Sixteen (29.1%) patients experienced the progression of tumors during the follow-up period (mean duration 47.7 months, range 12.4–132.1 months). Progression was occurred in 3 of 24 (12.5%) patients in group A, 3 of 20 (15.0%) patients in group B, and 10 of 11 (90.9%) patients in group C. The mean time to progression was 30.4 months (range 8.4–62.6 months); 46.2 months in group A, 36.5 months in group B, and 11.9 months in group C (p=0.041). Multivariate analysis showed that adjuvant treatment after surgery (HR 4.276, p<0.001), and Simpson grade (HR 2.572, p=0.040) predicted the recurrence of atypical meningiomas after incomplete resection. This retrospective case control study suggested that adjuvant treatment should be helpful to prevent the progression of atypical meningiomas after incomplete resection.