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Journal of Clinical Oncology, Vol 25, No 36 (December 20), 2007: pp. 5843-5844 © 2007 American Society of Clinical Oncology. DOI: 10.1200/JCO.2007.14.6092
Boost Dose Back Again in ElderlyDepartment of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey
Division of Medical Oncology, Selcuk University Faculty of Medicine, Konya, Turkey
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey To The Editor: We read with great interest the recent article by Bartelink et al addressing the impact of a 16-Gy boost radiation dose after breast-conserving therapy (BCT) on local control, survival, and fibrosis for patients with stage I and II breast cancer at 10 years follow-up.1 The authors reported the results of 5,318 patients with early breast cancer treated with microscopic complete excision and axillary dissection, followed by whole-breast irradiation to 50 Gy, who were randomly assigned to receive either no extra irradiation or a boost dose of 16 Gy to the original tumor bed. The authors demonstrated that addition of a boost dose of 16 Gy breast radiation significantly lowers the risk of local recurrence rates in all age groups, but does not seem to improve overall survival after 10 years of follow-up. We would like to point out a couple of significant points regarding their trial to clarify the outcome. First, their series revealed that 47% of the local recurrences occurred in the primary tumor bed, 10% occurred in the scar, 29% occurred outside the original tumor area, and 13% were diffuse. Since this trial aims to evaluate boost dose effect on local control, it seems unfair to categorize the elsewhere recurrences on local recurrence. We think that only recurrences in the primary tumor bed and scar region may reflect the real effect of boost dose on local control. Therefore, additional actuarial analysis of local control based on this criterion would be remarkable. As indicated by Bartelink et al, the boost dose was not the sole factor, which has a negative impact on the cosmetic outcome accompanied by the independent predictors as the location of the primary tumor in the lower quadrants of the breast, the volume of the excision, breast infection and/or hematoma, and clinical T2 stage. The first report of the trial with a 5-year follow-up indicated that the local control and cosmetic results are similar with interstitial implantation, photons, or electrons, such as did several other trials.2,3 Reporting the difference of the cosmetic results at 10-year follow-up between external boost and interstitial boost would also be valuable. The breast cancer mortality was detailed in the series, though no detail was given related with non–breast cancer mortality particularly in the left-sided breast cancer patients. It would be appealing to observe the possible effects of boost dose and cardiac effects, as well as the different modalities of boost that might change the cardiac effect. Additionally, Bartelink et al noted that microscopic complete excision of breast tumor should receive a boost dose of 16 Gy, but in a separate stratum of their trial, boost dose for microscopic incomplete excision were randomly assigned to receive a dose of either 10 or 26 Gy. If 16 Gy should be the dose after complete excision, why did the investigators choose a dose less than optimal for incomplete excision? Lastly, this report once again revealed one drawback of evidence (probability)-based medicine. The value of boost dose was shown with longer follow-up for elderly women whereas initial report demonstrated no significance. At that point, someone may wonder the consequences of this situation for elderly women who did not receive the boost dose during this period based on the preliminary findings of this trial. We would like to thank the authors for this important trial, and to state that clarification of these points above would possibly increase the credibility of this series to enlighten the related future work. AUTHOR'S DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST The author(s) indicated no potential conflicts of interest. REFERENCES
1. Bartelink H, Horiot JC, Poortmans PM, et al: Impact of a higher radiation dose on local control and survival in breast-conserving therapy of early breast cancer: 10-year results of the randomized boost versus no boost EORTC 22881-10882 trial. J Clin Oncol 25:3259-3265, 2007 2. De La Rochefordiére A, Abner A, Silver B, et al: Are cosmetic results following conservative surgery and radiotherapy for early breast cancer dependent on technique? Int J Radiat Oncol Biol Phys 23:925, 1992[Medline] 3. Perez CA, Garcia DM, Kuske RR, et al: Organ preservation therapy in stage T1 and T2 carcinoma of the breast. Front Radiat Ther Oncol 27:62-88, 1993[Medline]
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Copyright © 2007 by the American Society of Clinical Oncology, Online ISSN: 1527-7755. Print ISSN: 0732-183X
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