Glioblastoma multiforme (GBM) is the most malignant and frequent
brain tumor, with an aggressive growth pattern and poor prognosis despite best treatment modalities. Long-term survival of patients with GBM is rare.
Optic glioma represents 0.6-1.2% of all
brain tumors. Unlike low-grade
optic gliomas in children,
optic gliomas in adults are highly aggressive and death usually occurs in less than a year. Prolonged progression-free survival and survival rates have been reported in association with induced
hypothyroidism in two clinical trials for recurrent GBM. We present the clinical, radiological, and pathological findings in a patient with inoperable GBM of the optic chiasm. Following failure of initial, standard radiation and
temozolomide therapy, chemical
hypothyroidism was induced using the antithyroid
thioamide,
propylthiouracil, followed by
carboplatin chemotherapy. Initial
thyroid stimulating hormone, free T4, and free T3 analysis was carried out and then monthly. This patient responded rapidly to treatment (clinically and with
tumor regression within 4 weeks) on two separate occasions with an extended remission period (2.5 years) and prolonged overall survival (4.5 years). We report the successful long-term
tumor response to medically induced chemical
hypothyroidism in conjunction with carboplatinum
chemotherapy of an adult patient with grade IV GBM of the optic chiasm. These clinical observations find mechanistic support from the recent identification of potent mitogenic actions of the
thyroid hormone,
L-thyroxine, in
malignant glioma through binding to a cognate
thyroid hormone receptor on the αvβ3
integrin. Approaches to block its activity are now explored in preclinical studies.