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Title: Point/Counterpoint: Low-dose radiation is beneficial, not harmful

Abstract

No abstract prepared.

Authors:
 [1];  [2];
  1. Diagnostic Imaging, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111-2497 (United States)
  2. Radiation Epidemiology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-9778 (United States)
Publication Date:
OSTI Identifier:
22412480
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 41; Journal Issue: 7; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; BACKGROUND RADIATION; BIOLOGICAL ADAPTATION; BIOLOGICAL RADIATION EFFECTS; CARCINOGENESIS; CHROMOSOMAL ABERRATIONS; DNA DAMAGES; DNA REPAIR; HEALTH HAZARDS; RADICALS; STOCHASTIC PROCESSES; THRESHOLD DOSE; X RADIATION

Citation Formats

Doss, Mohan, E-mail: mohan.doss@fccc.edu, Little, Mark P., E-mail: mark.little@nih.gov, and Orton, Colin G. Point/Counterpoint: Low-dose radiation is beneficial, not harmful. United States: N. p., 2014. Web. doi:10.1118/1.4881095.
Doss, Mohan, E-mail: mohan.doss@fccc.edu, Little, Mark P., E-mail: mark.little@nih.gov, & Orton, Colin G. Point/Counterpoint: Low-dose radiation is beneficial, not harmful. United States. doi:10.1118/1.4881095.
Doss, Mohan, E-mail: mohan.doss@fccc.edu, Little, Mark P., E-mail: mark.little@nih.gov, and Orton, Colin G. Tue . "Point/Counterpoint: Low-dose radiation is beneficial, not harmful". United States. doi:10.1118/1.4881095.
@article{osti_22412480,
title = {Point/Counterpoint: Low-dose radiation is beneficial, not harmful},
author = {Doss, Mohan, E-mail: mohan.doss@fccc.edu and Little, Mark P., E-mail: mark.little@nih.gov and Orton, Colin G.},
abstractNote = {No abstract prepared.},
doi = {10.1118/1.4881095},
journal = {Medical Physics},
number = 7,
volume = 41,
place = {United States},
year = {Tue Jul 15 00:00:00 EDT 2014},
month = {Tue Jul 15 00:00:00 EDT 2014}
}
  • Analysis is made of the genetic effects of radiation on man based on the new data produced by G. G. Tinyakov (Doklady 9kad. Nauk S.S.R. 122, 598(1958)) which showed that the frequency of chromosome reorganization in ape sperm cells exposed to 400 r is considerably higher than that obtained in experiments with mice (on the 11th day after irradiation the number of nuclei damaged by chromosome reorganization in apes was 28.66%fl and in mice 11.12%. (R.V.J.)
  • Purpose: To assess how fraction size impacts lung radiation toxicity and therapeutic ratio in treatment of lung cancers. Methods and Materials: The relative damaged volume (RDV) of lung was used as the endpoint in the comparison of various fractionation schemes with the same normalized total dose (NTD) to the tumor. The RDV was computed from the biologically corrected lung dose-volume histogram (DVH), with an alpha/beta ratio of 3 and 10 for lung and tumor, respectively. Two different (linear and S-shaped) local dose-effect models that incorporated the concept of a threshold dose effect with a single parameter D{sub L50} (dose atmore » 50% local dose effect) were used to convert the DVH into the RDV. The comparison was conducted using four representative DVHs at different NTD and D{sub L50} values. Results: The RDV decreased with increasing dose/fraction when the NTD was larger than a critical dose (D{sub CR}) and increased when the NTD was less than D{sub CR}. The D{sub CR} was 32-50 Gy and 58-87 Gy for a small tumor (11 cm{sup 3}) for the linear and S-shaped local dose-effect models, respectively, when D{sub L50} was 20-30 Gy. The D{sub CR} was 66-97 Gy and 66-99 Gy, respectively, for a large tumor (266 cm{sup 3}). Hypofractionation was preferred for small tumors and higher NTDs, and conventional fractionation was better for large tumors and lower NTDs. Hypofractionation might be beneficial for intermediate-sized tumors when NTD = 80-90 Gy, especially if the D{sub L50} is small (20 Gy). Conclusion: This computational study demonstrated that hypofractionated stereotactic body radiotherapy is a better regimen than conventional fractionation in lung cancer patients with small tumors and high doses, because it generates lower RDV when the tumor NTD is kept unchanged.« less
  • Purpose: The clinical benefits and risks of dose escalation (DE) for stage III non–small-cell lung cancer (NSCLC) remain uncertain despite the results from Radiation Therapy Oncology Group (RTOG) protocol 0617. There is significant heterogeneity of practice, with many clinicians prescribing intermediate dose levels between the 0617 study arms of 60 and 74 Gy. This study investigated whether this strategy is associated with any survival benefits/risks by analyzing a large multi-institutional database. Methods and Materials: An individual patient database of stage III NSCLC patients treated with radical intent concurrent chemoradiation therapy was created (13 institutions, n=1274 patients). Patients were divided into 2more » groups based on tumor Biological Effective Dose at 10 Gy (BED 10): those receiving standard dose (SD; n=552), consisting of 72Gy ≤ BED 10 ≤ 76.8 Gy (eg 60-64 Gy/30-32 fractions [fr]), and those receiving intermediate dose (ID; n=497), consisting of 76.8Gy < BED 10 < 100.8 Gy (eg >64 Gy/32 fr and <74 Gy/37 fr), with lower-dose patients (n=225) excluded from consideration. Patients were then matched using propensity scores, leading to 2 matched groups of 196 patients. Outcomes were compared using various statistics including interquartile range (IQR), Kaplan-Meier curves, and adjusted Cox regression analysis. Results: Matched groups were found to be balanced except for N stage (more N3 disease in SD), median treatment year (SD in 2003; ID in 2007), platinum and taxane chemotherapy (SD in 28%; ID in 39%), and median follow-up (SD were 89 months; ID were 40 months). Median dose fractionation was 60 Gy/30 fr in SD (BED 10 IQR: 72.0-75.5 Gy) and 66 Gy/33 fr (BED 10 IQR: 78.6-79.2 Gy) in ID. Survival curves for SD and ID matched cohorts were statistically similar (P=.27); however, a nonstatistically significant trend toward better survival for ID was observed after 15 months (median survival SD: 19.3 months; ID: 21.0 months). There was an increase in grades III to V lung toxicity associated with ID (13.0% vs 4.9%, respectively). Conclusions: No significant overall survival benefits were found with intermediate DE; however, more grade III or greater lung toxicity was observed. The separation of survival curves after 15 months of follow-up suggests that a small overall survival improvement associated with intermediate DE cannot be excluded.« less