The Clinical Outcome of Hydroxyurea Chemotherapy after Incomplete Resection of Atypical Meningiomas

Background The aim of this study is to investigate the clinical results of adjuvant chemotherapy with hydroxyurea and to compare those with the results of postoperative radiotherapy after incomplete resection of atypical meningiomas (ATMNGs). Methods We retrospectively reviewed the medical records of 84 patients with ATMNGs diagnosed in the period from January 2000 to December 2014. Clinical data included patient sex and age at the time of surgery, presenting symptoms at diagnosis, location and size of tumor, extent of surgery, use of postoperative radiotherapy or hydroxyurea chemotherapy, duration of follow-up, and progression. In terms of the extent of surgical resection, incomplete resection was defined as Simpson grade II-V. Results Among the 85 patients, 55 (65.5%) patients underwent incomplete resection; 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). Twenty-five (45.5%) patients experienced the progression of tumors during the follow-up period (mean 47.7 months, range 12.4-132.1 months); 8 of 24 (33.3%) patients in group A, 7 of 20 (35.0%) patients in group B, and 10 of 11 (90.9%) patients in group C. The mean progression-free survival (PFS) was 30.9 months (range 6.4-62.3 months); 46.2 months in group A, 40.4 months in group B, and 11.9 months in group C (p=0.041). Multivariate analysis showed that Simpson grade (p=0.040), adjuvant treatment after surgery (p<0.001), increased Ki67 (p=0.017), mitotic index (p=0.034), and overexpression of p53 (p=0.026) predicted longer PFS. Conclusion This investigation suggested that adjuvant treatment after incomplete resection of ATMNGs are associated with longer PFS than conservative treatment, and that there is no difference of PFS between hydroxyurea chemotherapy and radiotherapy after surgery. Therefore, hydroxyurea chemotherapy can be considered as another adjuvant tool for the ATMNGs if the postoperative adjuvant radiotherapy cannot be applicable.