NEUROCYSTICERCOSIS AMONG PATIENTS WITH CEREBRAL GLIOMAS

Background: Parasites have been implicated in the pathogenesis of huma n cancer. Anecdotal reports have suggested an association between neur ocysticercosis and brain tumors. Objective: To determine whether neuro cysticercosis is a risk factor for cerebral glioma. Design: Case-contr ol study. Setting: A university general hospital and a cancer referral center. Patients: Forty-three consecutive patients with a cerebral gl ioma and 172 controls matched for age, sex, and socioeconomic status. Methods: We determined the ratio between the frequency of neurocystice rcosis in patients with a cerebral glioma and in matched controls. We also evaluated differences in the characteristics of the patients and in the histological type of the neoplasm among case patients with and without neurocysticercosis. In addition, we noted relationships betwee n the location of the cerebral glioma and that of parasitic lesions. R esults: Eight (16.8%) of 43 patients with a glioma and 5 (2.9%) of 172 controls had neurocysticercosis (P<.001). The odds ratio for this ass ociation was 7.63 (95% confidence interval, 2.03-31.09). Patients with glioma and neurocysticercosis were older than those without neurocyst icercosis (mean [+/-SD] age, 62.75+/-18.34 years vs 44.69+/-14.04 year s; P=.02). Glioblastoma multiforme was more frequent among case patien ts with neurocysticercosis than among those without neurocysticercosis (87.5% vs 48.6%); however, this difference was not statistically sign ificant (P=.24). Six of the 8 patients with neurocysticercosis and a c erebral glioma had calcified parasitic lesions within and around the t umor. Conclusions: Results from this study suggest that neurocysticerc osis is a risk factor for cerebral glioma. The intense astrocytic glio sis that surrounds calcified cysticerci, together with the suppression of the cellular immune response induced by cysticerci, may contribute to the development of malignant glial cells in patients with neurocys ticercosis.