- Email: [email protected]
In Response to Drs. Lavey and Olch
Letters to the Editor 2. Jensen AW, Isa Laack NN, Buckner JC, et al. Long-term follow-up of dose-adapted and reduced-field radiotherapy with or without chemotherapy for central nervous system germinoma. Int J Radiat Oncol Biol Phys Epub December 31, 2009. 3. Cho J, Choi J-U, Kim D-S, et al. Low-dose craniospinal irradiation as a definitive treatment for intracranial germinoma. Radiother Oncol 2009;91: 75–79. 4. Rogers SJ, Mosleh MA, Saran FH. Radiotherapy of localized intracranial germinoma: Time to sever historical ties? Lancet Oncol 2005;6: 509–519. 5. Matsutani M. Treatment of intracranial germ cell tumors: The second phase II study of Japanese GCT Study Group. NeuroOncol 2008;10: 420–421. 6. Calaminus G, Alapetite C, Frappaz D, et al. Outcome of localized and metastatic germinoma treated according to SIOP CNS GCT 96. NeuroOncol 2008;10:420.
IN RESPONSE TO DRS. LAVEY AND OLCH Intracranial germinoma (IG) occurs more commonly in East Asian countries, including Taiwan, than in Western countries. In our previously published 30-year statistical analysis (1975–2004), IG accounted for 7.6 % of all pediatric central nervous system tumors (1). We treat approximately 10 IG patients annually at Taipei Veterans General Hospital, representing onethird to one-half of all of Taiwan’s IG patients. Because IG is extremely radiosensitive and highly curable by radiotherapy (RT) alone, there is considerable interest in reducing the RT dose and volume to minimize the unacceptable toxicities for pediatric and adolescent patients. According to the literature (2) and analysis of our previous treatment results, pretreatment spinal seeding of IGs is an uncommon occurrence, and most post-treatment relapses occur within the ventricular system. Therefore, the conventional craniospinal irradiation (CSI) strategy for localized IG is controversial (3), because large-field irradiation is the predominant cause of neurotoxicities. Whole ventricular irradiation (WVI), including primary lesion sites, is the technique currently recommended to balance tumor control with RT toxicities (2, 4, 5). In addition, there is a worldwide trend to reduce the dose of radiation with or without adjuvant chemotherapy. However, there is no consensus in the field on a feasible lower limit of radiation dose for this radiosensitive tumor. Based on the rationale of reducing radiation dose or volume to achieve similar or even improved therapeutic outcomes, in 1996 we gradually started to treat clinically or pathologically diagnosed localized IG patients (without initial spinal seeding or high serum b-hCG level) with low-dose (30 Gy) and extended focal RT (WVI). We modified the irradiated volume between CSI and focal irradiation by tailoring the 3D conformal technique (including IMRT), and we attempted to avoid prescribing chemotherapy for patients with significant tumor regression after low-dose radiation (10–20 Gy with weekly computed tomographic examination during RT and routine magnetic resonance imaging after 30 Gy). None of the patients in our series were treated with only narrow focal irradiation. In a median follow-up time of 62.4 months, we observed that there were no significant survival differences
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between the RT-alone group and radio-chemotherapy group, demonstrating that this strategy leads to clinically acceptable outcomes. For germinomas derived from the basal ganglion or thalamus, we still use a similar strategy because our previous large cohort analysis did not reveal any relapses in the cerebral cortex (1, 6). Because the number of relapsed patients is quite small (3), it remains controversial whether every IG patient in this group should be treated with whole-brain irradiation. As the reported cases and associated data accumulate, an individualized response-dependent treatment strategy for IG is becoming increasingly feasible to achieve disease control and to minimize the negative sequelae of RT (7, 8). More case reports and longer follow-up times are necessary to improve treatment protocols for these fragile IG patients. SANG-HUE YEN, M.D. Cancer Center, Taipei Veterans General Hospital Department of Biomedical Imaging and Radiological Sciences National Yang-Ming University Taipei, Taiwan TAI-TONG WONG, M.D. Division of Pediatric Neurosurgery, Neurological Institute Taipei Veterans General Hospital Faculty of Medicine, National Yang-Ming University Taipei, Taiwan YI-WEI CHEN, M.D. PIN-I HUANG, M.D. Radiotherapy Division, Cancer Center, Taipei Veterans General Hospital Institute of Clinical Medicine, National Yang-Ming University Taipei, Taiwan doi:10.1016/j.ijrobp.2010.01.037 1. Wong TT, Ho DM, Chang KP, et al. Primary pediatric brain tumors: Statistics of Taipei VGH, Taiwan (1975–2004). Cancer 2005;104: 2156–2167. 2. Haas-Kogan DA, Missett BT, Wara WM, et al. Radiation therapy for intracranial germ cell tumors. Int J Radiat Oncol Biol Phys 2003;56: 511–518. 3. Rogers SJ, Mosleh-Shirazi MA, Saran FH. Radiotherapy of localised intracranial germinoma: Time to sever historical ties? Lancet Oncol 2005;6: 509–519. 4. Matsutani M. Treatment of intracranial germ cell tumors: The second phase II study of Japanese GCT Study Group. NeuroOncol 2008;10: 420–421. 5. Shirato H, Nishio M, Sawamura Y, et al. Analysis of long-term treatment of intracranial germinoma. Int J Radiat Oncol Biol Phys 1997;37:511–515. 6. Yen SH, Chen YW, Huang PI, et al. Optimal treatment for intracranial germinoma: Can we lower radiation dose without chemotherapy? Int J Radiat Oncol Biol Phys Epub October 27, 2009. 7. Shibamoto Y, Sasai K, Oya N, et al. Intracranial germinoma: Radiation therapy with tumor volume-based dose selection. Radiology 2001;218: 452–456. 8. Echevarrı´a ME, Fangusaro J, Goldman S. Pediatric central nervous system germ cell tumors: A review. Oncologist 2008;13:690–699.
IN RESPONSE TO DRS. LAVEY AND OLCH Intracranial germinoma (IG) occurs more commonly in East Asian countries, including Taiwan, than in Western countries. In our previously published 30-year statistical analysis (1975–2004), IG accounted for 7.6 % of all pediatric central nervous system tumors (1). We treat approximately 10 IG patients annually at Taipei Veterans General Hospital, representing onethird to one-half of all of Taiwan’s IG patients. Because IG is extremely radiosensitive and highly curable by radiotherapy (RT) alone, there is considerable interest in reducing the RT dose and volume to minimize the unacceptable toxicities for pediatric and adolescent patients. According to the literature (2) and analysis of our previous treatment results, pretreatment spinal seeding of IGs is an uncommon occurrence, and most post-treatment relapses occur within the ventricular system. Therefore, the conventional craniospinal irradiation (CSI) strategy for localized IG is controversial (3), because large-field irradiation is the predominant cause of neurotoxicities. Whole ventricular irradiation (WVI), including primary lesion sites, is the technique currently recommended to balance tumor control with RT toxicities (2, 4, 5). In addition, there is a worldwide trend to reduce the dose of radiation with or without adjuvant chemotherapy. However, there is no consensus in the field on a feasible lower limit of radiation dose for this radiosensitive tumor. Based on the rationale of reducing radiation dose or volume to achieve similar or even improved therapeutic outcomes, in 1996 we gradually started to treat clinically or pathologically diagnosed localized IG patients (without initial spinal seeding or high serum b-hCG level) with low-dose (30 Gy) and extended focal RT (WVI). We modified the irradiated volume between CSI and focal irradiation by tailoring the 3D conformal technique (including IMRT), and we attempted to avoid prescribing chemotherapy for patients with significant tumor regression after low-dose radiation (10–20 Gy with weekly computed tomographic examination during RT and routine magnetic resonance imaging after 30 Gy). None of the patients in our series were treated with only narrow focal irradiation. In a median follow-up time of 62.4 months, we observed that there were no significant survival differences
639
between the RT-alone group and radio-chemotherapy group, demonstrating that this strategy leads to clinically acceptable outcomes. For germinomas derived from the basal ganglion or thalamus, we still use a similar strategy because our previous large cohort analysis did not reveal any relapses in the cerebral cortex (1, 6). Because the number of relapsed patients is quite small (3), it remains controversial whether every IG patient in this group should be treated with whole-brain irradiation. As the reported cases and associated data accumulate, an individualized response-dependent treatment strategy for IG is becoming increasingly feasible to achieve disease control and to minimize the negative sequelae of RT (7, 8). More case reports and longer follow-up times are necessary to improve treatment protocols for these fragile IG patients. SANG-HUE YEN, M.D. Cancer Center, Taipei Veterans General Hospital Department of Biomedical Imaging and Radiological Sciences National Yang-Ming University Taipei, Taiwan TAI-TONG WONG, M.D. Division of Pediatric Neurosurgery, Neurological Institute Taipei Veterans General Hospital Faculty of Medicine, National Yang-Ming University Taipei, Taiwan YI-WEI CHEN, M.D. PIN-I HUANG, M.D. Radiotherapy Division, Cancer Center, Taipei Veterans General Hospital Institute of Clinical Medicine, National Yang-Ming University Taipei, Taiwan doi:10.1016/j.ijrobp.2010.01.037 1. Wong TT, Ho DM, Chang KP, et al. Primary pediatric brain tumors: Statistics of Taipei VGH, Taiwan (1975–2004). Cancer 2005;104: 2156–2167. 2. Haas-Kogan DA, Missett BT, Wara WM, et al. Radiation therapy for intracranial germ cell tumors. Int J Radiat Oncol Biol Phys 2003;56: 511–518. 3. Rogers SJ, Mosleh-Shirazi MA, Saran FH. Radiotherapy of localised intracranial germinoma: Time to sever historical ties? Lancet Oncol 2005;6: 509–519. 4. Matsutani M. Treatment of intracranial germ cell tumors: The second phase II study of Japanese GCT Study Group. NeuroOncol 2008;10: 420–421. 5. Shirato H, Nishio M, Sawamura Y, et al. Analysis of long-term treatment of intracranial germinoma. Int J Radiat Oncol Biol Phys 1997;37:511–515. 6. Yen SH, Chen YW, Huang PI, et al. Optimal treatment for intracranial germinoma: Can we lower radiation dose without chemotherapy? Int J Radiat Oncol Biol Phys Epub October 27, 2009. 7. Shibamoto Y, Sasai K, Oya N, et al. Intracranial germinoma: Radiation therapy with tumor volume-based dose selection. Radiology 2001;218: 452–456. 8. Echevarrı´a ME, Fangusaro J, Goldman S. Pediatric central nervous system germ cell tumors: A review. Oncologist 2008;13:690–699.