Treatment of Newly Diagnosed Germinomas
Germinomas are highly radiosensitive and have been traditionally treated with radiation therapy alone; historically, craniospinal irradiation with a boost to the region of the primary tumor has been utilized. This has resulted in 5-year overall survival rates greater than 90%.; [Level of evidence: 2A]; [3,4][Level of evidence: 3iA] These excellent survival rates have allowed investigators to focus on reducing radiation treatment volume and intensity in an attempt to decrease late effects.[2,5] Patterns of relapse following craniospinal irradiation versus reduced-volume radiation therapy (whole-brain or whole-ventricular radiation therapy) have strongly suggested that craniospinal irradiation is not necessary for localized germinomas.[6,7] Based on these results, the treatment for patients with localized germinomas has been modified to cover the whole ventricular system followed by a boost to the primary site, rather than to deliver radiation therapy to the entire craniospinal axis or even to the whole brain. This change has not resulted in worse outcomes and is expected to minimize the acute and long-term toxicity of radiation therapy.
Chemotherapy has been explored in an effort to reduce radiation therapy doses and associated neurodevelopmental morbidity. Several studies have confirmed the feasibility of this approach maintaining excellent survival rates, but the number of treated patients is still small.[8-10]; [Level of evidence: 2A]; [Level of evidence: 3iiiC] Chemotherapy agents such as cyclophosphamide, ifosfamide, etoposide, cisplatin, and carboplatin are highly active in central nervous system (CNS) germinomas. Management of patients receiving chemotherapeutics that require hyperhydration (e.g., cyclophosphamide, ifosfamide, and cisplatin) are often quite challenging to manage because of the high prevalence of diabetes insipidus in this population. An international group of investigators have explored a chemotherapy-only approach primarily for younger children. They were able to achieve a complete response in 84% of patients with germinomas treated with chemotherapy alone. Fifty percent of these patients relapsed or progressed; many recurrences were local, local plus ventricular, and ventricular alone and/or with leptomeningeal dissemination throughout the CNS requiring further therapy including radiation. Subsequent studies have continued to support the need for irradiation following chemotherapy and the likely requirement for whole-ventricular irradiation when chemoradiotherapy is used in order to avoid ventricular recurrence.[Level of evidence: 2A]; [Level of evidence: 3iiiA]
The appropriate dose and field of radiation therapy given following chemotherapy has not been established. The treatment options for localized pure germinoma include whole-ventricular radiation therapy with 24 Gy followed by a boost to the primary tumor for a total dose of 45 Gy to 50 Gy. Chemotherapy followed by reduced-dose radiation therapy could also be considered. However, the extent of dose reduction of radiation therapy has not been established, and whether the whole-ventricular irradiation dose (following chemotherapy) can be further reduced to primary tumor bed alone has not been established.
Optimal management of bifocal lesions is unclear. A meta-analysis of 60 patients demonstrated excellent progression-free survival after craniospinal irradiation alone. Chemotherapy plus localized radiation, including whole-ventricular irradiation, also resulted in excellent disease control.[Level of evidence: 3iiDiii]
The following two standards of care exist for the treatment of newly diagnosed germinomas:
- Radiation therapy alone.
- Neoadjuvant chemotherapy followed by response-based reductions in radiation therapy.
The following is an example of a national and/or institutional clinical trial that is currently being conducted or is under analysis. Information about ongoing clinical trials is available from the NCI Web site.
- COG-ACNS1123 (Chemotherapy Followed by Radiation Therapy in Treating Younger Patients With Newly Diagnosed Localized CNS GCTs): COG-ACNS1123 is a Children’s Oncology Group cooperative multi-institutional trial. This phase II trial of response-based radiation therapy for patients with localized CNS GCTs will compare the event-free survival and overall survival rates of a short course of chemotherapy followed by response-based whole-ventricular radiation with a boost to the primary site. For patients who obtain a complete response, the whole-ventricular radiation dose will be 25% lower than the standard whole-ventricular dose; the standard whole-ventricular dose will be used for patients who have less than a complete response after chemotherapy with or without second-look surgery.
- 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 (2): 285-90, 1988. [PUBMED Abstract]
- Cho J, Choi JU, Kim DS, et al.: Low-dose craniospinal irradiation as a definitive treatment for intracranial germinoma. Radiother Oncol 91 (1): 75-9, 2009. [PUBMED Abstract]
- Huang PI, Chen YW, Wong TT, et al.: Extended focal radiotherapy of 30 Gy alone for intracranial synchronous bifocal germinoma: a single institute experience. Childs Nerv Syst 24 (11): 1315-21, 2008. [PUBMED Abstract]
- Eom KY, Kim IH, Park CI, et al.: Upfront chemotherapy and involved-field radiotherapy results in more relapses than extended radiotherapy for intracranial germinomas: modification in radiotherapy volume might be needed. Int J Radiat Oncol Biol Phys 71 (3): 667-71, 2008. [PUBMED Abstract]
- Chen MJ, Santos Ada S, Sakuraba RK, et al.: Intensity-modulated and 3D-conformal radiotherapy for whole-ventricular irradiation as compared with conventional whole-brain irradiation in the management of localized central nervous system germ cell tumors. Int J Radiat Oncol Biol Phys 76 (2): 608-14, 2010. [PUBMED Abstract]
- Rogers SJ, Mosleh-Shirazi MA, Saran FH: Radiotherapy of localised intracranial germinoma: time to sever historical ties? Lancet Oncol 6 (7): 509-19, 2005. [PUBMED Abstract]
- Shikama N, Ogawa K, Tanaka S, et al.: Lack of benefit of spinal irradiation in the primary treatment of intracranial germinoma: a multiinstitutional, retrospective review of 180 patients. Cancer 104 (1): 126-34, 2005. [PUBMED Abstract]
- Kretschmar C, Kleinberg L, Greenberg M, et al.: Pre-radiation chemotherapy with response-based radiation therapy in children with central nervous system germ cell tumors: a report from the Children's Oncology Group. Pediatr Blood Cancer 48 (3): 285-91, 2007. [PUBMED Abstract]
- Allen JC, DaRosso RC, Donahue B, et al.: A phase II trial of preirradiation carboplatin in newly diagnosed germinoma of the central nervous system. Cancer 74 (3): 940-4, 1994. [PUBMED Abstract]
- Buckner JC, Peethambaram PP, Smithson WA, et al.: Phase II trial of primary chemotherapy followed by reduced-dose radiation for CNS germ cell tumors. J Clin Oncol 17 (3): 933-40, 1999. [PUBMED Abstract]
- Khatua S, Dhall G, O'Neil S, et al.: Treatment of primary CNS germinomatous germ cell tumors with chemotherapy prior to reduced dose whole ventricular and local boost irradiation. Pediatr Blood Cancer 55 (1): 42-6, 2010. [PUBMED Abstract]
- O'Neil S, Ji L, Buranahirun C, et al.: Neurocognitive outcomes in pediatric and adolescent patients with central nervous system germinoma treated with a strategy of chemotherapy followed by reduced-dose and volume irradiation. Pediatr Blood Cancer 57 (4): 669-73, 2011. [PUBMED Abstract]
- Afzal S, Wherrett D, Bartels U, et al.: Challenges in management of patients with intracranial germ cell tumor and diabetes insipidus treated with cisplatin and/or ifosfamide based chemotherapy. J Neurooncol 97 (3): 393-9, 2010. [PUBMED Abstract]
- Balmaceda C, Heller G, Rosenblum M, et al.: Chemotherapy without irradiation--a novel approach for newly diagnosed CNS germ cell tumors: results of an international cooperative trial. The First International Central Nervous System Germ Cell Tumor Study. J Clin Oncol 14 (11): 2908-15, 1996. [PUBMED Abstract]
- da Silva NS, Cappellano AM, Diez B, et al.: Primary chemotherapy for intracranial germ cell tumors: results of the third international CNS germ cell tumor study. Pediatr Blood Cancer 54 (3): 377-83, 2010. [PUBMED Abstract]
- Alapetite C, Brisse H, Patte C, et al.: Pattern of relapse and outcome of non-metastatic germinoma patients treated with chemotherapy and limited field radiation: the SFOP experience. Neuro Oncol 12 (12): 1318-25, 2010. [PUBMED Abstract]
- Weksberg DC, Shibamoto Y, Paulino AC: Bifocal intracranial germinoma: a retrospective analysis of treatment outcomes in 20 patients and review of the literature. Int J Radiat Oncol Biol Phys 82 (4): 1341-51, 2012. [PUBMED Abstract]