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Journal of Clinical Oncology, Vol 24, No 17 (June 10), 2006: pp. 2685-2686 © 2006 American Society of Clinical Oncology. DOI: 10.1200/JCO.2006.06.3289
In Reply:Department of Radiation Oncology, Cancer Hospital, Chinese Academy of Medical Sciences (CAMS) and Peking Union Medical College (PUMC), Beijing, China Bahl et al have addressed an important issue of radiation dose and technique for patients with nasal natural-killer (NK)/T-cell lymphoma. Several previous studies including ours have suggested radiotherapy (RT) as primary treatment for early-stage nasal NK/T-cell lymphoma.1-4 However, few studies have specifically addressed the radiation technique, such as radiation dose and field, for this particular disease.5-8 Koom et al6 from Korea reported that in 102 patients with stage I to II nasal-type NK/T-cell lymphoma of the head and neck treated with radiotherapy alone, the complete response rate was 72% and the local failure was 47%. Similarly, higher local failure after RT with or without chemotherapy (CT) was also observed in other studies. This high local failure can be partly explained by the relative lower radiation dose used in these retrospective studies.6-9 Shikama et al7 reported that the 5-year local control was significantly higher with a total dose of 50 Gy or more as compared with less than 50 Gy (100% v 67%; P = .013). In agreement with these data, Isobe et al8 reported a local failure of 67% for less than 50 Gy and 27% for 50 Gy or more in nasal-type NK/T-cell lymphoma (P = .038). In another study from Koom et al, 6 a median dose of 45 Gy was used, and local failure was 64% for less than 45 Gy as compared with 38% for 45 Gy or more (P = .02). Although this study demonstrated a dose-response relation within the range of 20 to 54 Gy with a plateau at doses in excess of approximately 54 Gy, it should be pointed out that radiation dose of 45 Gy is not optimal for radical RT of nasal NK/T-cell lymphoma and may contribute to extremely high local failure in this series. You et al4 administered higher radiotherapy doses of 54 to 60 Gy and achieved a 5-year failure-free survival rate of 83.3%. On the other hand, small radiation target volume also resulted in a higher local failure.8 In our study, the majority of patients (91 [89%] of 102) received a radiation dose of 50 Gy or more to the primary tumor, whereas only 11 patients (11% of 102) with nasal NK/T cell lymphoma received less than 50 Gy.1 The distributions of RT doses in RT-alone arm and combined-modality therapy (CMT) arm are shown in Table 1. The higher proportion of 40 to 45 Gy and 56 to 65 Gy in the CMT arm can be partly explained by extranodal progression and bulky disease, respectively. In our institution, a total dose of 50 to 55 Gy to the primary tumor was considered as radical radiation dose for nasal NK/T-acell lymphoma, and additional 10 Gy was administered as a boost if there was residual disease after the completion of 50 to 55 Gy. Furthermore, the large radiation field was used in our series of patients with nasal NK/T-cell lymphoma. For patients with primary tumor confined to the nasal cavity (limited-stage IE), clinical target encompassed the bilateral nasal cavity, hard plate, ipsilateral maxillary sinus, and bilateral anterior ethmoid sinuses. It also included the nasopharynx when the primary tumor was close to the posterior nasal aperture.10 For those patients with extensive stage IE and IIE disease, the clinical target volume was extended to the involved paranasal organs/tissues or cervical lymph nodes. With the large radiation fields and high doses to the nasal cavity and neighboring organs or structures, we observed a very low local failure of 7.8% (eight patients) in 102 patients receiving RT with or without CT.1 In our series, the patterns of failure were mainly distant extranodal disseminations (25 [23.8%] of 105 patients), followed by lymph nodes (11 [10.5%] of 105 patients), and local sites (nine [8.6%] of 105 patients). For the latter nine patients with local progression or relapse, the failure was located in the irradiated field in seven of them, whereas in one patient it was a marginal failure. Another patient developed a local relapse after CT alone. Only one (3%) of 37 patients with limited-stage IE developed local relapse, whereas eight (12%) of 68 patients with extensive stage IE and stage IIE disease experienced local progression or relapse. All of the latter patients had primary tumor extended into adjacent structures or organs. No significant differences were observed among the three treatment modalities (RT alone, 3.2%; CT + RT, 13.5%; RT + CT, 5.9%; P = .254) although a relative high local failure (13.5%) was observed in CT + RT. Because of the small numbers of patients receiving low doses of 40 to 45 Gy or high doses of more than 50 Gy, we did not find a dose-response relationship between local failure and RT doses. The overall local failure rates were 9.1% (one of 11 patients) for 40 to 45 Gy, 8.1% (six of 74 patients) for 50 to 55 Gy, and 5.9% (one of 17 patients) for 56 to 65 Gy, respectively (P = .941). On the basis of these data, it is necessary to deliver at least 50 Gy of radiation to achieve a favorable local control rate, and to use a large clinical target for early-stage nasal NK/T-cell lymphoma.
Authors' Disclosures of Potential Conflicts of Interest The authors indicated no potential conflicts of interest.
REFERENCES
1. Li YX, Yao B, Jin J, et al: Radiotherapy as primary treatment for stage IE and IIE nasal natural killer/T Cell Lymphoma. J Clin Oncol 24:181-189, 2006 2. Chim CS, Ma SY, Au WY, et al: Primary nasal natural killer cell lymphoma: Long-term treatment outcome and relationship with the international prognostic index. Blood 103:216-221, 2004 3. Li CC, Tien HF, Tang JL, et al: Treatment outcome and pattern of failure in 77 patients with sinonasal natural killer/T-cell or T-cell lymphoma. Cancer 100:366-375, 2004[CrossRef][Medline] 4. You JY, Chi KH, Yang MH, et al: Radiation therapy versus chemotherapy as initial treatment for localized nasal natural killer (NK)/T-cell lymphoma: A single institute survey in Taiwan. Ann Oncol 15:618-625, 2004 5. Kim GE, Cho JH, Yang WI, et al: Angiocentric lymphoma of the head and neck: Patterns of systemic failure after radiation treatment. J Clin Oncol 18:54-63, 2000 6. Koom WS, Chung EJ, Yang WI, et al: Angiocentric T-cell and NK/T-cell lymphomas: Radiotherapeutic viewpoints. Int J Radiat Oncol Biol Phys 59:1127-1137, 2004[CrossRef][Medline] 7. Shikama N, Izuno I, Oguchi M, et al: Clinical stage IE primary lymphoma of the nasal cavity: Radiation therapy and chemotherapy. Radiology 204:467-470, 1997 8. Isobe K, Uno T, Tamaru JI, et al: Extranodal natural killer/T-cell lymphoma, nasal type. Cancer 106:609-615, 2006[Medline] 9. Cheung MMC, Chan JK, Lau WH, et al: Early stage nasal T/NK-cell lymphoma: Clinical outcome, prognostic factors, and the effect of treatment modality. Int J Radiat Oncol Biol Phys 54:182-190, 2002[Medline] 10. Li YX, Coucke PA, Li JY, et al: Primary non-Hodgkin's lymphoma of the nasal cavity: Prognostic significance of paranasal extension and the role of radiotherapy and chemotherapy. Cancer 83:449-456, 1998[CrossRef][Medline]
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Copyright © 2006 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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