- Email: [email protected]
In Reply to Bahl et al.
Letters to the Editor NIKHILESH PATIL, MD London Regional Cancer Program University of Western Ontario London, ON, Canada doi:10.1016/j.ijrobp.2011.12.043 1. Ryu S-Y, Lee W-M, Lee E-D, et al. Randomized clinical trial of weekly vs. triweekly cisplatin-based chemotherapy concurrent with radiotherapy in the treatment of locally advanced cervical cancer. Int J Radiat Oncol Biol Phys 2001;81:e577–e581. 2. Lyman GH. Impact of chemotherapy dose intensity on cancer patient outcomes. J Natl Compr Canc Netw 2009;7:99–108.
INCREASED RISK OF ISCHEMIC STROKE IN YOUNG NASOPHARYNGEAL CARCINOMA PATIENTS. IN REGARD TO LEE ET AL. (INT J RADIAT ONCOL BIOL PHYS 2011;81:E833–E838) To the Editor: We read with interest the article by Lee et al., ‘‘Increased risk of ischemic stroke in young nasopharyngeal carcinoma patients’’ (1). The authors have done an interesting and relevant research in studying stroke rates in nasopharyngeal cancer patients as quality-of-life issues are becoming increasingly relevant with advances and refinements in both radiotherapy and chemotherapy techniques and increased survival rates of patients. However, the article makes no mention of the range of radiation doses used for patient treatment and the radiation techniques used to treat these patients. It would have been interesting and clinically relevant to see a correlation between radiation doses and incidence of stroke. The radiation technique used can make a significant difference in the dose delivered to the carotid arteries. The analysis also included postoperative patients undergoing adjuvant radiotherapy. However, there is no mention if the stroke rates in postoperative patients were different from those under radical chemoradiotherapy. It is also not clear whether patients undergoing reirradiation were included in this analysis. Vitolo et al. (2) compared radiation doses to carotid arteries using intensity-modulated radiotherapy (IMRT) vs. conventional three field radiotherapy. With dose constraints to the carotid arteries, the mean carotid dose was 54 Gy in the IMRT vs. 58.4 Gy in the three-field technique. Rosenthal et al. (3) reported median carotid V35, V50, and V63 doses of 100%, 100%, and 69%, respectively, in T1– 2 glottic cancers treated by conventional planning. These reduced to 2%, 0%, and 0%, respectively (p \ 0.01) with IMRT using carotid sparing. Conformal techniques, especially IMRT, are increasingly being used to treat carcinoma nasopharynx. Long-term follow-up of patients undergoing IMRT, especially with carotid sparing technique, is likely to reduce the incidence of carotid artery–related morbidity in head and neck cancer patients. In a study by Bahl et al. (4), the mean dose to the carotid vessels in the extended-field IMRT in cancer nasopharynx patients was 63.88 0.97 Gy (mean dose SD), and it was 64.43 0.73 Gy for the split-field technique (using separate single anterior field to treat lower neck nodes). The integral dose in the extended-field vs. split-field technique was 0.29 0.0207 and 0.32 0.0213 L/Gy, respectively. We also feel that the carotid duplex scanning in nasopharyngeal cancer patients treated with modern radiation techniques needs additional evaluation before it can be advocated as a routine screening procedure. AMIT BAHL, M.D., D.N.B., M.N.A.M.S. S. GHOSHAL, M.D. S.C. SHARMA, M.D. Department of Radiotherapy and Regional Cancer Center Postgraduate Institute of Medical Education and Research Chandigarh, India doi:10.1016/j.ijrobp.2011.11.015 1. Lee CC, Su YC, Ho HC, et al. Increased risk of ischemic stroke in young nasopharyngeal carcinoma patients. Int J Radiat Oncol Biol Phys 2011; 81:e833–e838. 2. Vitolo V, Millender LE, Quivey JM, et al. Assessment of carotid artery dose in the treatment of nasopharyngeal cancer with IMRT versus conventional radiotherapy. Radiother Oncol 2009;90:213–220. 3. Rosenthal DI, Fuller CD, Barker JL Jr., et al. Simple carotid-sparing intensity-modulated radiotherapy technique and preliminary experience for T1-2 glottic cancer. Int J Radiat Oncol Biol Phys 2010;77:455–461. 4. Bahl A, Basu KSJ, Sharma DN, et al. Integral dose to the carotid artery in intensity modulated radiotherapy of carcinoma nasopharynx: Extended field IMRT versus split-field IMRT. J Cancer Res Ther 2010;6:585–587.
1321 IN REPLY TO BAHL ET AL.
To the Editor: We appreciate the comments of Dr. Amit Bahl et al. on our article, ‘‘Increased Risk of Ischemic Stroke in Young Nasopharyngeal Carcinoma Patients.’’ Definitive radiotherapy (RT) for nasopharyngeal carcinoma is typically given to a total dose of 70–72 Gy to the primary tumor and 50 Gy to the neck (1). For more advanced disease, a similar dosing schedule is used, with 66–70 Gy to involved neck lymph nodes. Although dose data were unavailable and patients undergoing reirradiation were excluded in our population-based study, all nasopharyngeal carcinoma patients included who undergo radiotherapy or chemoradiotherapy reach the threshold for the development of ischemic stroke (2). However, our study cannot rule out the effect of an additional 15–20 Gy to the neck for more advanced disease. The radiation techniques were not included in our database, and future studies with more detailed radiotherapy are necessary. The effect of different treatment modality for ischemic stroke was analyzed. After adjusting for other factors, neither chemoradiotherapy (hazard ratio = 0.57; 95% confidence interval, 0.29–1.12) nor surgery with adjuvant therapy (hazard ratio = 0.75; 95% confidence interval, 0.30–1.90) conferred a higher risk than radiotherapy alone in our series. Screening of high-risk groups such as patients undergoing head and neck radiotherapy for asymptomatic carotid stenosis could be cost-effective (3). The problem is when to do it: soon after or several years after radiotherapy or chemoradiotherapy? Our data demonstrate that the shortest latency between radiation and ischemic stroke was 5–6 years in patients without any vascular risk factors and 0–2 years in patients with 1 or more vascular risk factors. Further studies are necessary to evaluate stroke risk associated with newer radiotherapy strategies in head and neck cancer. CHING-CHIH LEE, M.D., PH.D. Community Medicine Research Center and Institute of Public Health National Yang-Ming University Taipei, Taiwan, Department of Otolaryngology and Cancer Center School of Medicine Tzu Chi University Hualian, Taiwan PESUS CHOU, PH.D. Community Medicine Research Center and Institute of Public Health National Yang-Ming University Taipei, Taiwan YUNG-SUNG HUANG, M.D. Division of Neurology Department of Internal Medicine Buddhist Dalin Tzu Chi General Hospital Chiayi, Taiwan doi:10.1016/j.ijrobp.2011.11.014 1. Wei WI, Sham JS. Nasopharyngeal carcinoma. Lancet 2005;365: 2041–2054. 2. Smith GL, Smith BD, Buchholz TA, et al. Cerebrovascular disease risk in older head and neck cancer patients after radiotherapy. J Clin Oncol 2008;26:5119–5125. 3. Derdeyn CP, Powers WJ. Cost-effectiveness of screening for asymptomatic carotid atherosclerotic disease. Stroke 1996;27:1944–1950.
DOES SACRIFICING THE DEEP LOBE OF PAROTID GLAND PREVENT MARGINAL MISS? IN REGARD TO CHEN ET AL. (INT J RADIAT ONCOL BIOL PHYS 2011;80:1423–1429) To the Editor: We have read the article by Chen et al. (1) with great interest. The authors reported the outcome of postoperative intensitymodulated radiotherapy (IMRT) in 90 patients with head-and-neck cancer. They achieved an 80% local regional control rate at 2 years and reported 17 failures. Of these 17 failures, 6 were marginal, and 3 of those marginal failures were a result of parotid sparing in the contralateral neck. The authors concluded that the findings of this study may be useful for clinical target volume (CTV) design in the future because the geographic misses were not insignificant. We have a couple of concerns regarding this article. First, there is consensus for CTV delineation in definitive head-andneck cancer (2), as the authors mentioned in their article. However, those guidelines are applicable for N0 neck. They cannot be put in practice for patients with multiple metastatic lymph nodes or in patients receiving
INCREASED RISK OF ISCHEMIC STROKE IN YOUNG NASOPHARYNGEAL CARCINOMA PATIENTS. IN REGARD TO LEE ET AL. (INT J RADIAT ONCOL BIOL PHYS 2011;81:E833–E838) To the Editor: We read with interest the article by Lee et al., ‘‘Increased risk of ischemic stroke in young nasopharyngeal carcinoma patients’’ (1). The authors have done an interesting and relevant research in studying stroke rates in nasopharyngeal cancer patients as quality-of-life issues are becoming increasingly relevant with advances and refinements in both radiotherapy and chemotherapy techniques and increased survival rates of patients. However, the article makes no mention of the range of radiation doses used for patient treatment and the radiation techniques used to treat these patients. It would have been interesting and clinically relevant to see a correlation between radiation doses and incidence of stroke. The radiation technique used can make a significant difference in the dose delivered to the carotid arteries. The analysis also included postoperative patients undergoing adjuvant radiotherapy. However, there is no mention if the stroke rates in postoperative patients were different from those under radical chemoradiotherapy. It is also not clear whether patients undergoing reirradiation were included in this analysis. Vitolo et al. (2) compared radiation doses to carotid arteries using intensity-modulated radiotherapy (IMRT) vs. conventional three field radiotherapy. With dose constraints to the carotid arteries, the mean carotid dose was 54 Gy in the IMRT vs. 58.4 Gy in the three-field technique. Rosenthal et al. (3) reported median carotid V35, V50, and V63 doses of 100%, 100%, and 69%, respectively, in T1– 2 glottic cancers treated by conventional planning. These reduced to 2%, 0%, and 0%, respectively (p \ 0.01) with IMRT using carotid sparing. Conformal techniques, especially IMRT, are increasingly being used to treat carcinoma nasopharynx. Long-term follow-up of patients undergoing IMRT, especially with carotid sparing technique, is likely to reduce the incidence of carotid artery–related morbidity in head and neck cancer patients. In a study by Bahl et al. (4), the mean dose to the carotid vessels in the extended-field IMRT in cancer nasopharynx patients was 63.88 0.97 Gy (mean dose SD), and it was 64.43 0.73 Gy for the split-field technique (using separate single anterior field to treat lower neck nodes). The integral dose in the extended-field vs. split-field technique was 0.29 0.0207 and 0.32 0.0213 L/Gy, respectively. We also feel that the carotid duplex scanning in nasopharyngeal cancer patients treated with modern radiation techniques needs additional evaluation before it can be advocated as a routine screening procedure. AMIT BAHL, M.D., D.N.B., M.N.A.M.S. S. GHOSHAL, M.D. S.C. SHARMA, M.D. Department of Radiotherapy and Regional Cancer Center Postgraduate Institute of Medical Education and Research Chandigarh, India doi:10.1016/j.ijrobp.2011.11.015 1. Lee CC, Su YC, Ho HC, et al. Increased risk of ischemic stroke in young nasopharyngeal carcinoma patients. Int J Radiat Oncol Biol Phys 2011; 81:e833–e838. 2. Vitolo V, Millender LE, Quivey JM, et al. Assessment of carotid artery dose in the treatment of nasopharyngeal cancer with IMRT versus conventional radiotherapy. Radiother Oncol 2009;90:213–220. 3. Rosenthal DI, Fuller CD, Barker JL Jr., et al. Simple carotid-sparing intensity-modulated radiotherapy technique and preliminary experience for T1-2 glottic cancer. Int J Radiat Oncol Biol Phys 2010;77:455–461. 4. Bahl A, Basu KSJ, Sharma DN, et al. Integral dose to the carotid artery in intensity modulated radiotherapy of carcinoma nasopharynx: Extended field IMRT versus split-field IMRT. J Cancer Res Ther 2010;6:585–587.
1321 IN REPLY TO BAHL ET AL.
To the Editor: We appreciate the comments of Dr. Amit Bahl et al. on our article, ‘‘Increased Risk of Ischemic Stroke in Young Nasopharyngeal Carcinoma Patients.’’ Definitive radiotherapy (RT) for nasopharyngeal carcinoma is typically given to a total dose of 70–72 Gy to the primary tumor and 50 Gy to the neck (1). For more advanced disease, a similar dosing schedule is used, with 66–70 Gy to involved neck lymph nodes. Although dose data were unavailable and patients undergoing reirradiation were excluded in our population-based study, all nasopharyngeal carcinoma patients included who undergo radiotherapy or chemoradiotherapy reach the threshold for the development of ischemic stroke (2). However, our study cannot rule out the effect of an additional 15–20 Gy to the neck for more advanced disease. The radiation techniques were not included in our database, and future studies with more detailed radiotherapy are necessary. The effect of different treatment modality for ischemic stroke was analyzed. After adjusting for other factors, neither chemoradiotherapy (hazard ratio = 0.57; 95% confidence interval, 0.29–1.12) nor surgery with adjuvant therapy (hazard ratio = 0.75; 95% confidence interval, 0.30–1.90) conferred a higher risk than radiotherapy alone in our series. Screening of high-risk groups such as patients undergoing head and neck radiotherapy for asymptomatic carotid stenosis could be cost-effective (3). The problem is when to do it: soon after or several years after radiotherapy or chemoradiotherapy? Our data demonstrate that the shortest latency between radiation and ischemic stroke was 5–6 years in patients without any vascular risk factors and 0–2 years in patients with 1 or more vascular risk factors. Further studies are necessary to evaluate stroke risk associated with newer radiotherapy strategies in head and neck cancer. CHING-CHIH LEE, M.D., PH.D. Community Medicine Research Center and Institute of Public Health National Yang-Ming University Taipei, Taiwan, Department of Otolaryngology and Cancer Center School of Medicine Tzu Chi University Hualian, Taiwan PESUS CHOU, PH.D. Community Medicine Research Center and Institute of Public Health National Yang-Ming University Taipei, Taiwan YUNG-SUNG HUANG, M.D. Division of Neurology Department of Internal Medicine Buddhist Dalin Tzu Chi General Hospital Chiayi, Taiwan doi:10.1016/j.ijrobp.2011.11.014 1. Wei WI, Sham JS. Nasopharyngeal carcinoma. Lancet 2005;365: 2041–2054. 2. Smith GL, Smith BD, Buchholz TA, et al. Cerebrovascular disease risk in older head and neck cancer patients after radiotherapy. J Clin Oncol 2008;26:5119–5125. 3. Derdeyn CP, Powers WJ. Cost-effectiveness of screening for asymptomatic carotid atherosclerotic disease. Stroke 1996;27:1944–1950.
DOES SACRIFICING THE DEEP LOBE OF PAROTID GLAND PREVENT MARGINAL MISS? IN REGARD TO CHEN ET AL. (INT J RADIAT ONCOL BIOL PHYS 2011;80:1423–1429) To the Editor: We have read the article by Chen et al. (1) with great interest. The authors reported the outcome of postoperative intensitymodulated radiotherapy (IMRT) in 90 patients with head-and-neck cancer. They achieved an 80% local regional control rate at 2 years and reported 17 failures. Of these 17 failures, 6 were marginal, and 3 of those marginal failures were a result of parotid sparing in the contralateral neck. The authors concluded that the findings of this study may be useful for clinical target volume (CTV) design in the future because the geographic misses were not insignificant. We have a couple of concerns regarding this article. First, there is consensus for CTV delineation in definitive head-andneck cancer (2), as the authors mentioned in their article. However, those guidelines are applicable for N0 neck. They cannot be put in practice for patients with multiple metastatic lymph nodes or in patients receiving