Radiotherapy of germinomas involving the basal ganglia and thalamus

Multi-institutional analysis of treatment modalities in basal ganglia and thalamic germinoma

BACKGROUND

Central nervous system (CNS) germinomas are treatment-sensitive tumors with excellent survival outcomes. Current treatment strategies combine chemotherapy with radiotherapy (RT) in order to reduce the field and dose of RT. Germinomas originating in the basal ganglia/thalamus (BGTGs) have proven challenging to treat given their rarity and poorly defined imaging characteristics. Craniospinal (CSI), whole brain (WBI), whole ventricle (WVI), and focal RT have all been utilized; however, the best treatment strategy remains unclear.

METHODS

Retrospective multi-institutional analysis has been conducted across 18 institutions in four countries.

RESULTS

For 43 cases of nonmetastatic BGTGs, the 5- and 10-year event-free survivals (EFS) were 85.8% and 81.0%, respectively, while the 5- and 10-year overall survivals (OS) were 100% and 95.5%, respectively (one patient fatality from unrelated cause). Median RT doses were as follows: CSI: 2250 cGy/cGy(RBE) (1980-2400); WBI: 2340 cGy/cGy(RBE) (1800-3000); WVI: 2340 cGy/cGy(RBE) (1800-2550); focal: 3600 cGy (3060-5400). Thirty-eight patients (90.5%) received chemotherapy. There was no statistically significant difference in the EFS based on initial field extent (p = .84). Nevertheless, no relapses were reported in patients who received CSI or WBI. Chemotherapy alone had significantly inferior EFS compared to combined therapy (p = .0092), but patients were salvageable with RT.

CONCLUSION

Patients with BGTGs have excellent outcomes and RT proved to be an integral component of the treatment plan. This group of patients should be included in future prospective clinical trials and the best RT field should be investigated further.

Treatment outcomes based on radiation therapy fields for bifocal germinoma: Synchronous or disseminated disease?

Intracranial germinoma sometimes present as bifocal germinoma, and whether bifocal germinoma should be treated as a synchronous or disseminated disease remains unclear. This study aimed to determine the optimal treatment modality for bifocal germinoma. Patients with bifocal germinoma who received radiotherapy (RT) from March 1990 to August 2017 were included for analysis. A total of 21 patients were included. The median follow-up period was 76.2 months (range, 6.2-305.4 months). There were 17 patients who received cranio-spinal irradiation (CSI) with local RT; 3, whole ventricular RT (WVRT) with local RT; and 1, local RT only. Three recurrences occurred (1 patient each among those who underwent CSI, WVRT, and local RT). Recurrence in the patient who received CSI and who received WVRT occurred in the right thalamus and right frontal convexity, respectively. Meanwhile, the patient who received local RT showed not only a recurred lesion in the hypothalamus, but also cerebrospinal fluid seeding. For this patient, salvage CSI was performed and complete response was achieved after treatment. However, after 9 years and 6 months, he was diagnosed with glioblastoma and expired. As for toxicity, although 17 patients showed decrease in complete blood count levels during treatment, all patients recovered soon after treatment completion. Our findings suggest that bifocal germinoma may be considered as a disseminated disease when considering the patterns of failure according to RT fields. In addition, patients who received CSI showed low acute toxicity rates. However, further studies are necessary to confirm these findings.

Pattern of relapse and outcome of non-metastatic germinoma patients treated with chemotherapy and limited field radiation: the SFOP experience

Over the last two decades, chemotherapy has been introduced in protocols for patients with intracranial germinoma with the objective of reducing the volume and the dose of irradiation without compromising survival rates. The aim of this work is to critically analyze the pattern of relapse in a cohort of patients with nonmetastatic germinoma prospectively treated with chemotherapy followed by focal field radiation. Data of all germinoma patients registered in the French protocol for intracranial germ cell tumors between 1990 and 1999 were reviewed. The pattern of relapse, management, and outcome were analyzed in 10 of 60 patients who developed a recurrence after initial treatment. In 9 patients, the site of recurrence was local or loco-regional, notably in the periventricular area for 8. One patient only had isolated distant leptomeningeal relapse. The review of the sites of relapse suggests that most recurrences could have been avoided with a larger ventricular field of radiation. Treatment at first relapse included chemotherapy (10 patients), high-dose chemotherapy and stem cell transplant (8 patients), and/or radiation therapy (4 patients). Five patients experienced a second relapse. At a median follow-up of 72 months since the first relapse, 8 patients are alive in second or third remission. This review identified an excess of periventricular relapses when the focal field of radiation is used in the combined management of germinoma. These relapses are predominantly marginal or outside radiation fields. Ventricular field radiation appears a logical alternative to decrease the incidence of such relapses. Future trials should aim at better identifying patients who may benefit from local and ventricular radiation, respectively.

Inherent diagnostic and treatment challenges in germinoma of the basal ganglia: a case report and review of the literature

Among intracranial germinomas, basal ganglia germinomas represent a specific clinical and anatomical entity. Based on an unusual case of a basal ganglia germinoma in a 13-year-old Caucasian male, we highlight the diagnostic challenges and discuss treatment considerations in this disease.

Impacts of elevated level of hCG in serum on clinical course and radiotherapy results in the histology-confirmed intracranial germinomas

The prognosis of intracranial germinoma producing the human chorionic gonadotropin (hCG) is controversial due to limited information. We undertook a retrospective analysis to determine whether this type of tumor has similar clinical course and prognosis to hCG non-secreting germinoma. Thirty-one histologically confirmed intracranial germinoma patients who had pretreatment hCG examination in serum/CSF were treated with radiotherapy between 1980 and 1996. hCG level was measured by immunoradioassay of beta subunit of hCG. Six patients had elevated serum hCG levels and were defined as having hCG secreting germinoma. All except three patients received craniospinal axis irradiation. The follow-up ranged from 19-175 months with a median of 63 months. hCG secreting germinoma accounted for 19% of intracranial germinoma cases. Elevated hCG levels ranged from 39-260 IU/l in serum. No difference was found between hCG non-secreting germinoma and hCG secreting germinoma in terms of patient or treatment characteristics. There was no recurrence among the six hCG secreting germinoma patients. The 5-year overall and disease-free survival rates were 96% for patients with hCG non-secreting germinomas and 100% for the patients with hCG secreting germinomas. The survival difference was not significant (p = 0.59). Our results suggest that elevated level of hCG did not result in any differences in the clinical characteristics or survival after radical radiotherapy in histologically confirmed intracranial germinoma.

Radiotherapy of intracranial germinomas

Between 1980 and 1992, 32 patients with intracranial germinomas were treated with radiation. All patients were confirmed histopathologically prior to treatment. Of the 32 intracranial germinomas reviewed, 14 were located in the suprasellar region, 12 in the basal ganglia and thalamus, four in the pineal, and two in both the pineal and suprasellar regions. Three patients had subarachnoid seeding. Craniospinal irradiation was undertaken for 29 patients. The median dose of 54 Gy was delivered to the tumor bed, 36 Gy to the whole brain and 24 Gy to the spinal axis. Five and 10-year survival rates were 96.9 and 96.9%, respectively. Local control was achieved in all patients except one who died of persistent tumor after 2 months following radiotherapy. No intracranial recurrence or spinal metastasis were found. Tumor site did not relate to the prognosis. One patient developed severe intellectual deterioration, three patients had vertebral growth impairment. The present study confirms the excellent result with radiotherapy alone for patients with germinomas.