Intracranial germinoma: treatment with radiosurgery alone--a case report

Journal of Neuro-Oncology 37: 75–77, 1998.  1998 Kluwer Academic Publishers. Printed in the Netherlands.

Clinical Study

Intracranial germinoma: Treatment with radiosurgery alone A case report

William F. Regine,1 Jonathan E. Hodes2 and Roy A. Patchell2 University of Kentucky Medical Center, Department of Radiation Medicine, Lexington; 2University of Kentucky Medical Center, Department of Neurosurgery, Lexington, KY 40536-0084, USA

1

Key words: intracranial germinoma, radiosurgery Summary The management of intracranial germinomas is controversial, with treatment options including conventional wide-field irradiation with or without chemotherapy or primary chemotherapy alone. The potential role of radiosurgery in the treatment of these lesions, although appealing, remains to be defined. We report a case whose initial management plan included radiosurgery to be followed by chemotherapy; however the patient subsequently refused chemotherapy. The presentation, diagnosis, treatment and results are discussed.

The treatment of intracranial germinomas is controversial. Therapeutic options include conventional wide-field external beam irradiation or chemotherapy either alone or in combination [1–6]. A primary aim of evolving treatment strategies is the minimization of radiation exposure to normal brain in this young patient population [1, 2]. Use of stereotactic radiosurgery in these patients is therefore an attractive consideration; however its role remains to be defined. The authors describe a case of an intracranial germinoma whose treatment involved use of radiosurgery alone.

Case report A 25 year old male presented to his primary care physician with a complaint of transient fainting episodes and/or blurring of vision for several minutes. He was referred to us after a magnetic resonance image (MRI) of the head revealed a 2.5 × 1.7 × 1.5 cm enhancing lesion of the left thalamic region.

Diagnosis The patient underwent stereotactic biopsy of the lesion. Pathologic examination identified a germ cell neoplasm consistent with germinoma. Systemic and neuraxis workup, including serum and cerebrospinal fluid beta HCG and alpha fetoprotein levels, were within normal limits.

Treatment Given the known radiation and chemosensitivity of this tumor histology, and the potential late effects associated with conventional wide-field irradiation, it was recommended the patient be treated with radiosurgery followed by chemotherapy. The patient therefore, with the Leksell Gamma-Knife*, received a single dose of 14 Gy to a conformally shaped 40% isodose shell encompassing the enhancing tumor margin (Figure 1A). However, the patient refused subsequent planned chemotherapy. * Elekta Radiosurgery Inc., Atlanta, GA

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Figure 1a. Radiosurgery plan used to deliver 14 Gy to the conformally shaped 40% isodose encompassing the enhancing left thalamic germinoma.

Figure 1b. Follow-up MRI at 2 years status post radiosurgery showing no evidence of residual tumor.

Results

recent literature reviews indicate a 20% risk of neuraxis seeding with use of such an approach for histologically documented intracranial germinomas [3, 6]. Thus, the need for craniospinal irradiation in these patients remains controversial. Nevertheless, as with other brain tumors, the potential sequelae of irradiation affecting a young patient population has led investigators to evaluate the use of adjunctive or primary chemotherapy in an attempt to reduce external beam irradiation dose and volume, or eliminate its use completely [1, 2]. Use of radiosurgery in combination with chemotherapy is an attractive treatment consideration in patients with intracranial germinomas. Unlike conventional wide-field irradiation it would theoretically allow delivery of highly localized irradiation to the primary tumor with the sparing of potentially subclinically involved surrounding normal brain or neuraxis to be addressed by chemotherapy. In addition, use of tumor markers such as B-HCG to select favorable low-risk patients [2] may allow use of planned radiosurgery alone for those agreeable to close follow-up examinations, while reserving con-

The first follow-up MRI at 3 months, and the most recent at 2 years, status post radiosurgery, show no evidence of residual disease (Figure 1B). The patient is doing well and has experienced no significant transitory or permanent complications noted on follow-up clinical or MRI exams performed at 3–6 month intervals.

Discussion A literature review reveals that this is the first reported case of a primary intracranial germinoma treated with radiosurgery alone; although the initial intent of treatment was for radiosurgery to be followed by chemotherapy. The radiocurability of intracranial germinomas is well established with longterm cure rates approaching 100% following conventional wide-field external beam irradiation [3, 4, 6]. Although excellent results from small series using local wide-field irradiation have been reported,

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77 ventional wide-field irradiation and/or chemotherapy as salvage for those failing to show significant response early on. Further information and experience is clearly needed before considering such approaches outside a study setting.

References 1. Allen JC, Kim JH, Packer RJ: Neoadjuvant chemotherapy for newly diagnosed germ cell tumors of the central nervous system. J Neurosurg 67: 65–70, 1987 2. Balmaceda C, Finlay J, Heller G, et al.: Prognostic factors at diagnosis in patients with primary CNS germ cell tumors. Proc Am Clin Oncol 13: 176, 1994

3. Dearnaley DP, A’Hern RP, Whittaker S, et al.: Pineal and CNS germ cell tumors: Royal Marsden Hospital experience 1962– 1987. Int J Radiat Oncol Biol Phys 18: 773–781, 1990 4. Jenkins D, Berry M, Chan H, et al.: Pineal region germinomas in childhood treatment consideration. Int J Radiat Oncol Biol Phys 18: 541–545, 1990 5. Linstadt D, Wara WM, Edwards MSB, et al.: Radiotherapy of primary intracranial germinomas: the case against routine craniospinal irradiation. Int J Radiat Oncol Biol Phys 15: 291–297, 1988 6. Shibamoto Y, Abe M, Yamashita J, et al.: Treatment results of intracranial germinoma as a function of the irradiated volume. Int J Radiat Oncol Biol Phys 15: 285–290, 1988 Address for offprints: W.F. Regine, University of Kentucky Medical Center, Department of Radiation Medicine, 800 Rose Street, Lexington, KY 40536-0084, USA

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