DOCSLIB.ORG

The Impact of County-Level Radiation Oncologist Density on Prostate Cancer Mortality in the United States

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Impact of County-Level Radiation Oncologist Density on Prostate Cancer Mortality in the United States Prostate Cancer and Prostatic Diseases (2012) 15, 391 -- 396 & 2012 Macmillan Publishers Limited All rights reserved 1365-7852/12 www.nature.com/pcan ORIGINAL ARTICLE The impact of county-level radiation oncologist density on prostate cancer mortality in the United States S Aneja1 and JB Yu1,2,3 BACKGROUND: The distribution of radiation oncologists across the United States varies significantly among geographic regions. Accompanying these variations exist geographic variations in prostate cancer mortality. Prostate cancer outcomes have been linked to variations in urologist density, however, the impact of geographic variation in the radiation oncologist workforce and prostate cancer mortality has yet to be investigated. The goal of this study was to determine the effect of increasing radiation oncologist density on regional prostate cancer mortality. METHODS: Using county-level prostate cancer mortality data from the National Cancer Institute and Centers for Disease Control as well as physician workforce and health system data from the Area Resource File a regression model was built for prostate cancer mortality controlling for categorized radiation oncologist density, urologist density, county socioeconomic factors and pre-existing health system infrastructure. RESULTS: There was statistically significant reduction in prostate cancer mortality (3.91--5.45% reduction in mortality) in counties with at least 1 radiation oncologist compared with counties lacking radiation oncologists. However, increasing the density of radiation oncologists beyond 1 per 100 000 residents did not yield statistically significant incremental reductions in prostate cancer mortality. CONCLUSIONS: The presence of at least one radiation oncologist is associated with significant reductions in prostate cancer mortality within that county. However, the incremental benefit of increasing radiation oncologist density exhibits a plateau effect providing marginal benefit. In order to optimize outcomes a geographically aware policy, which addresses the size and distribution of the workforce, must be in place in order prevent geographic disparities in prostate cancer mortality. Prostate Cancer and Prostatic Diseases (2012) 15, 391--396; doi:10.1038/pcan.2012.28; published online 24 July 2012 Keywords: access to care; physician workforce; radiation oncologist density INTRODUCTION cancer, the association between the availability of radiation As the demand for cancer care increases, equitable access to oncologists and prostate cancer mortality merits exploration. oncology services is critical to improving cancer mortality and Furthermore, the relative impact of the distribution of radiation optimizing outcomes. Though evidence indicates that prostate oncologists, urologists and primary care providers on prostate cancer mortality has been improving in recent years, the benefit cancer mortality is unknown. from modern cancer treatment may not be uniform throughout It is likely that the geographic distribution of radiation the United States.1,2 Furthermore, given the aging US population, oncologists is important to the receipt of cancer treatment, the incidence of prostate cancer is expected to increase particularly for those patients who are not candidates for surgery. dramatically over the next 20 years. Whether the current physician Alternatively, patients who are surgical candidates, but refuse workforce is adequately and equitably distributed, to meet and surgery, may choose radiation therapy as an alternative curative optimize the growing demand for cancer care, is an important treatment if a radiation oncologist is geographically accessible. area of ongoing study.3--6 External beam radiotherapy, the dominant form of radiation Several types of providers are involved in the diagnosis and treatment in the United States, typically requires multiple daily treatment of prostate cancer. Primary care providers and radiation treatments for 6--9 weeks, making the geographic urologists are typically involved in initial diagnosis, whereas distribution of radiation oncologists more important, particularly urologists, medical oncologists and radiation oncologists could for patients with limited mobility and resources for travel. Recent all potentially be involved in the primary treatment of prostate evidence has found a geographic maldistribution of the radiation cancer. It is well known that access to primary care is an oncology workforce throughout the United States, with radiation important predictor of cancer-specific mortality.7 Therefore, oncologists clustering in metropolitan locations.6 As it is known some argue that increasing the number of primary care that travel time to the nearest cancer center varies significantly physicians, rather than specialists, is the most efficient way to throughout the country, inequities in geographic access may be improve health outcomes for the entire US population.8 associated with variations in cancer mortality.9 We initiated this However, growing evidence suggests that for prostate cancer, study to elucidate whether the density of radiation oncologists specialist density does impact outcomes.5 As radiation oncolo- within in a county was related to variations in prostate cancer gists also serve as primary treatment providers for prostate mortality. 1Yale School of Medicine Department of Therapeutic Radiology, New Haven, CT, USA; 2Cancer Outcomes, Public Policy, and Effectiveness Research (COPPER) Center at Yale, New Haven, CT, USA and 3Yale Cancer Center, New Haven, CT, USA. Correspondence: Dr JB Yu, Yale School of Medicine Department of Therapeutic Radiology, 333 Cedar Street New Haven, CT 06515, USA. E-mail: [email protected] Received 28 March 2012; revised 17 May 2012; accepted 10 June 2012; published online 24 July 2012 Radiation oncologist density and prostate cancer mortality S Aneja and JB Yu 392 MATERIALS AND METHODS Statistical analysis Data sources A model was built with prostate cancer mortality per 100 000 people as the The geographic units of analysis in this study were the 3141 counties in the primary outcome variable. In an effort to better examine if incremental United States as defined by the 2000 Census. Similar to previous studies changes in physician density accompany changes in prostate cancer investigating the impact of physician density on cancer-related mortality, mortality, radiation oncologist and urologist densities were categorized rural counties were excluded from the analysis because only 0.4% of the (0, 0.1--1.0, 1.1--2, 2.1--4.0, 44.0 per 100 000 people). Different radiation 669 rural counties in the United States possessed radiation oncologists and oncologist density categories were mapped using the mapping software many of them lacked complete mortality data.4,10 Following exclusion of ArcGIS version 9.2 (Environmental Systems Research Institute, Inc., rural counties, 2472 non-rural counties composing B78.7% of the United Redlands, CA, USA). Univariate associations between physician workforce, States possessed complete mortality data and were available for analysis. health system and socioeconomic predictor variables and cancer mortality Counties were classified as rural based on 2003 Department of Agriculture were calculated using t-tests for categorical variables and linear regression Rural/Urban Continuum Codes. Physician data were obtained using the for continuous variables. Multivariate regression models were built using 2008 Area Resource File.11 Published by the Health Resources and Services backward stepwise selection with a univariate Po0.15 for inclusion into Administration of the US Department of Health and Human Services, the the models. Allergist--immunologist density was manually inserted into the ARF is a collection of data from over 50 sources, including the American final model to control for changes in cancer mortality that could potentially Medical Association, American Hospitalization Association, US Census, and be attributed to a high overall specialist density. Statistically insignificant National Center for US Health Statistics. The ARF aggregates information allergist--immunologist density in the final model would suggest changes concerning healthcare professionals, healthcare facilities and population in cancer mortality were likely unattributed to high overall specialist for each county in the United States, and includes the number of density. To account for potential geographic variations in prostate cancer specialists within each county based on data from the American Medical screening, prostate cancer incidence among counties in the United States Association Physician Masterfile. In addition to physician data, geographic, was also included in the model. Statistical significance for the final models health system and demographic data for each county were collected from was determined at Po0.05. Variance inflation factors were used to control the ARF in effort to account for ecological characteristics that could for excessive collinearity amongst variables. Percent changes in mortality potentially influence cancer outcomes. Prostate cancer mortality and were calculated for each density category using the cancer mortality incidence data were obtained from a merged data set from the National of a reference group. The reference group in all three models was a Cancer Institute’s Surveillance, Epidemiology and End Results program, county with no radiation oncologists, urologists or allergists. To evaluate National Program for Cancer Registries and United States Center for incremental benefits
Load more

Recommended publications
  • Internal Radiation Therapy, Places Radioactive Material Directly Inside Or Next to the Tumor
    Brachytherapy Brachytherapy is a type of radiation therapy used to treat cancer. It places radioactive sources inside the patient to kill cancer cells and shrink tumors. This allows your doctor to use a higher total dose of radiation to treat a smaller area in less time. Your doctor will tell you how to prepare and whether you will need medical imaging. Your doctor may use a computer program to plan your therapy. What is brachytherapy and how is it used? External beam radiation therapy (EBRT) directs high-energy x-ray beams at a tumor from outside the body. Brachytherapy, also called internal radiation therapy, places radioactive material directly inside or next to the tumor. It uses a higher total dose of radiation to treat a smaller area in less time than EBRT. Brachytherapy treats cancers throughout the body, including the: prostate - see the Prostate Cancer Treatment (https://www.radiologyinfo.org/en/info/pros_cancer) page cervix - see the Cervical Cancer Treatment (https://www.radiologyinfo.org/en/info/cervical-cancer-therapy) page head and neck - see the Head and Neck Cancer Treatment (https://www.radiologyinfo.org/en/info/hdneck) page skin breast - see the Breast Cancer Treatment (https://www.radiologyinfo.org/en/info/breast-cancer-therapy) page gallbladder uterus vagina lung - see the Lung Cancer Treatment (https://www.radiologyinfo.org/en/info/lung-cancer-therapy) page rectum eye Brachytherapy is seldom used in children. However, brachytherapy has the advantage of using a highly localized dose of radiation. This means that less radiation is delivered to surrounding tissue. This significantly decreases the risk of radiation-induced second malignancies, a serious concern in children.
    [Show full text]
  • Standards for Radiation Oncology
    Standards for Radiation Oncology Radiation Oncology is the independent field of medicine which deals with the therapeutic applications of radiant energy and its modifiers as well as the study and management of cancer and other diseases. The American College of Radiation Oncology (ACRO) is a nonprofit professional organization whose primary purposes are to advance the science of radiation oncology, improve service to patients, study the socioeconomic aspects of the practice of radiation oncology, and provide information to and encourage continuing education for radiation oncologists, medical physicists, and persons practicing in allied professional fields. As part of its mission, the American College of Radiation Oncology has developed a Practice Accreditation Program, consisting of standards for Radiation Oncology and standards for Physics/External Beam Therapy. Accreditation is a voluntary process in which professional peers identify standards indicative of a high quality practice in a given field, and which recognizes entities that meet these high professional standards. Each standard in ACRO’s Practice Accreditation Program requires extensive peer review and the approval of the ACRO Standards Committee as well as the ACRO Board of Chancellors. The standards recognize that the safe and effective use of ionizing radiation requires specific training, skills and techniques as described in this document. The ACRO will periodically define new standards for radiation oncology practice to help advance the science of radiation oncology and to improve the quality of service to patients throughout the United States. Existing standards will be reviewed for revision or renewal as appropriate on their third anniversary or sooner, if indicated. The ACRO standards are not rules, but rather attempts to define principles of practice that are indicative of high quality care in radiation oncology.
    [Show full text]
  • Radiological Protection Issues in Endovascular Use of Radiation Sources
    IAEA-TECDOC-1488 Radiological protection issues in endovascular use of radiation sources February 2006 IAEA SAFETY RELATED PUBLICATIONS IAEA SAFETY STANDARDS Under the terms of Article III of its Statute, the IAEA is authorized to establish or adopt standards of safety for protection of health and minimization of danger to life and property, and to provide for the application of these standards. The publications by means of which the IAEA establishes standards are issued in the IAEA Safety Standards Series. This series covers nuclear safety, radiation safety, transport safety and waste safety, and also general safety (i.e. all these areas of safety). The publication categories in the series are Safety Fundamentals, Safety Requirements and Safety Guides. Safety standards are coded according to their coverage: nuclear safety (NS), radiation safety (RS), transport safety (TS), waste safety (WS) and general safety (GS). Information on the IAEA’s safety standards programme is available at the IAEA Internet site http://www-ns.iaea.org/standards/ The site provides the texts in English of published and draft safety standards. The texts of safety standards issued in Arabic, Chinese, French, Russian and Spanish, the IAEA Safety Glossary and a status report for safety standards under development are also available. For further information, please contact the IAEA at P.O. Box 100, A-1400 Vienna, Austria. All users of IAEA safety standards are invited to inform the IAEA of experience in their use (e.g. as a basis for national regulations, for safety reviews and for training courses) for the purpose of ensuring that they continue to meet users’ needs.
    [Show full text]
  • Of Suvranu Ganguli Supporting the Yttrium-90 Microsphere
    'Page 1 of2 As of: 12/18/17 4:23 PM Received: December 17, 2017 . ' · Status: Pending_Post PUBLIC SUBMISSION Tracking No . .lkl-90ef-jm8z Comments Due: January 08, 2018 Submission Type: API Docket: NRC-2017-0215 Yttrium-90 Microsphere Brachytherapy Sources and Devices Therasphere and SIR-Spheres Comment On: NRC-2017-0215-0001 Yttrium-90 Microsphere Brachytherapy Sources and Devices TheraSphere and SIR-Spheres; Draft Guidance for Comment Document: NRC-2017-0215-DRAFT-0108 Comment on FR Doc# 2017-24129 I - -- Submitter Information /I / 1 / cJ-1)/ 7 p ~ ~A,c!J7?~-- Name: Suvranu Ganguli Address: Massachusetts General Hospital 55 Fruit Street, GRB 298 Boston, MA, 02114 Email: [email protected] Organization: Massachusetts General Hospital/Harvard Medical School General Comment Dear Nuclear Regulatory Commission, I am a practicing interventional radiologist/oncologist at Massachusetts General Hospital and an Assistant Professor of Radiology at Harvard Medical School, and have been practicing for over 8 years. I have utiilzed Y-90 radioembolization on hundreds of patients over that time, and I am an authorized used for both Sir-Spheres and Theraspheres at my hospital. I have worked closely with Sirtex for may years in treating my patients. I endorse the Sirtex response to the NRC proposed amendment, which is supplied below. Thank you for your consideration, SUNSI Review Complete Template = ADM - 013 E-RIDS= ADM -03 "­ https://www.fdms.gov/fdms/getcontent?objectid=0900006482< Add= A· :!);uJL/eY/ek_&eJ:t-.) 12/18/2017 Page 2 of2 Suvranu Ganguli, MD Attachments Sirtex Response to NRC Proposed Changes Oct 2016 https://www.fdms.gov/fdms/getcontent?objectid=0900006482d22499&format=xml&showorig=false 12/18/2017 SIRThX Sirtex Response to Proposed Changes to the Yttrium-90 Microsphere Brachytherapy Sources and Devices Licensing Guidance Statement to the U.S.
    [Show full text]
  • A Framework for Quality Radiation Oncology Care
    Safety is No Accident A FRAMEWORK FOR QUALITY RADIATION ONCOLOGY CARE DEVELOPED AND SPONSORED BY Safety is No Accident A FRAMEWORK FOR QUALITY RADIATION ONCOLOGY CARE DEVELOPED AND SPONSORED BY: American Society for Radiation Oncology (ASTRO) ENDORSED BY: American Association of Medical Dosimetrists (AAMD) American Association of Physicists in Medicine (AAPM) American Board of Radiology (ABR) American Brachytherapy Society (ABS) American College of Radiology (ACR) American Radium Society (ARS) American Society of Radiologic Technologists (ASRT) Society of Chairmen of Academic Radiation Oncology Programs (SCAROP) Society for Radiation Oncology Administrators (SROA) T A R G E T I N G CAN CER CAR E The content in this publication is current as of the publication date. The information and opinions provided in the book are based on current and accessible evidence and consensus in the radiation oncology community. However, no such guide can be all-inclusive, and, especially given the evolving environment in which we practice, the recommendations and information provided in the book are subject to change and are intended to be updated over time. This book is made available to ASTRO and endorsing organization members and to the public for educational and informational purposes only. Any commercial use of this book or any content in this book without the prior written consent of ASTRO is strictly prohibited. The information in the book presents scientific, health and safety information and may, to some extent, reflect ASTRO’s and the endorsing organizations’ understanding of the consensus scientific or medical opinion. ASTRO and the endorsing organizations regard any consideration of the information in the book to be voluntary.
    [Show full text]
  • RADIATION ONCOLOGY TRAINING PROGRAM CURRICULUM Page 2 © 2012 RANZCR
    The Royal Australian and New Zealand College of Radiologists® RADIATION ONCOLOGY TRAINING PROGRAM CURRICULUM Page 2 © 2012 RANZCR. Radiation Oncology Training Program Curriculum Foreward by the Chief Censor incorporates direct clinical management of patients of CURRICULUM all ages, with a uniquely effective treatment modality. INTRODUCTION With the discovery of X-rays in the late 19th century and It is a specialty that will allow you to have meaningful the study of radioactivity by Marie Curie and colleagues interactions with patients and their families, and to be in the early 1900s, came a new era in medicine. The a key player in their overall care. realisation that some types of radiation (X-rays, electrons and gamma rays from radioactive materials) destroy Again, welcome. malignant cells, infinitely expanded our capacity to treat cancer. Over the last 100 years, the full potential of radiation in curing many cancer patients, and relieving distressing symptoms (palliation) for others, has unfolded. This stream of medicine has grown into the modern A/Prof. Sandra Turner specialty of Radiation Oncology. Chief Censor Radiation Oncology Clinicians who specialise in Radiation Oncology play an integral role in the complex multidisciplinary team management of cancer patients. Their practice is strongly underpinned by a detailed knowledge of the biological effects and physics of radiation, of pathology and anatomy as they relate to cancer and its control, and of the application of sophisticated imaging and treatment technologies. Paramount is an extensive understanding of all clinical aspects of cancer management. Radiation Oncologists are trained to be competent beyond their role as clinical and technical experts.
    [Show full text]
  • Standards for Oncology Registry Entry STORE 2018
    STandards for Oncology Registry Entry STORE 2018 Effective for Cases Diagnosed January 1, 2018 STORE STandards for Oncology Registry Entry Released 2018 (Incorporates all updates to Commission on Cancer, National Cancer Database Data standards since FORDS was revised in 2016) Effective for cases diagnosed January 1, 2018 See Appendix A for Updates since FORDS: Revised for 2016. Version 1.0 © 2018 AMERICAN COLLEGE OF SURGEONS All Rights Reserved STORE 2018 Table of Contents Table of Contents Table of Contents ......................................................................................................................... ii Foreword ..................................................................................................................................... 1 FROM “FORDS” TO “STORE” ..................................................................................................................... 1 Preface 2018 ................................................................................................................................ 2 Comorbidities and Complications ............................................................................................................. 2 Revisions to Staging Requirements ........................................................................................................... 2 Staging Data Items No Longer Required for Cases Diagnosed in 2018 and Later (Required for Cases Diagnosed 2017 and Earlier) ................................................................................................................
    [Show full text]
  • Stereotactic Radiosurgery
    Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiotherapy (SBRT) Stereotactic radiosurgery (SRS) is a non-surgical radiation therapy used to treat functional abnormalities and small tumors of the brain. It can deliver precisely-targeted radiation in fewer high-dose treatments than traditional therapy, which can help preserve healthy tissue. When SRS is used to treat body tumors, it's called stereotactic body radiotherapy (SBRT). SRS and SBRT are usually performed on an outpatient basis. Ask your doctor if you should plan to have someone drive you home afterward and whether you should refrain from eating or drinking or taking medication several hours before treatment. Tell your doctor if there's a possibility you are pregnant or if you're breastfeeding or if you're taking oral medication or insulin to control diabetes. Discuss whether you have an implanted medical device, claustrophobia or allergies to contrast materials. What is stereotactic radiosurgery and how is it used? Stereotactic radiosurgery (SRS) is a highly precise form of radiation therapy initially developed to treat small brain tumors and functional abnormalities of the brain. The principles of cranial SRS, namely high precision radiation where delivery is accurate to within one to two millimeters, are now being applied to the treatment of body tumors with a procedure known as stereotactic body radiotherapy (SBRT). Despite its name, SRS is a non-surgical procedure that delivers precisely-targeted radiation at much higher doses, in only a single or few treatments, as compared to traditional radiation therapy. This treatment is only possible due to the development of highly advanced radiation technologies that permit maximum dose delivery within the target while minimizing dose to the surrounding healthy tissue.
    [Show full text]
  • The Role of the Radiation Oncologist in Systemic Therapy
    dicine Me & r R a a d Leung, J Nucl Med Radiat Ther 2012, S:6 le i c a u t i DOI: 10.4172/2155-9619.S6-006 o Journal of N n f T o l h a e n r r ISSN: 2155-9619a u p o y J Nuclear Medicine & Radiation Therapy Review Article Open Access The Role of the Radiation Oncologist in Systemic Therapy - an Australian and New Zealand Perspective John Leung* Adelaide Radiotherapy Centre, Adelaide, South Australia, Australia Abstract There has been considerable recent interest in radiation oncologists becoming more involved in prescribing systemic therapy. Radiation oncology and medical oncology have been very distinct disciplines with little overlap in Australia and New Zealand. However, the Faculty of Radiation Oncology identified systemic therapy as a priority to be investigated. The subsequent workforce survey in 2010 found that although the majority of radiation oncologists and trainees were not interested in becoming more involved in systemic therapy, there was still considerable interest. This manuscript identifies the key issues to consider if radiation oncologists are contemplating being more involved with systemic therapy. Keywords: Radiation oncologist; Systemic therapy In lung cancer, chemotherapy is not just administered for combined modality treatment in stage three diseases or for palliation in stage four Introduction disease, but can be given as adjuvant treatment for earlier stage disease. Radiation Oncology is the medical specialty where ionizing There appears to be a marked decline in radiation oncologists radiation is used as part of cancer treatment to control malignant prescribing systemic therapy in Australian and New Zealand.
    [Show full text]
  • Proton Therapy—Frequently Asked Questions
    PROTON THERAPY—FREQUENTLY ASKED QUESTIONS What is the difference between proton therapy and conventional radiation? Traditional radiation therapy uses photons to treat tumors. Photons radiate not only tumor cells but also everything in their path, including healthy cells and structures around and behind the tumor. Proton therapy uses protons to treat tumors. Protons can be controlled better than conventional radiation, making this treatment more precise and accurate. As a result, proton therapy can treat tumors without radiation continuing past the tumor (an “exit dose” of radiation). This protects surrounding tissues from harm. How does proton therapy work? Proton therapy uses pencil beam scanning to deliver radiation and match each tumor’s exact shape and size in 3-D. This allows a single layer of a tumor to be treated at a time, in effect painting the tumor with radiation layer-by-layer and slice-by-slice until the entire area has been treated. What are the benefits of proton therapy? Proton therapy is more accurate and precise than most other forms of radiation therapy. Because it involves significantly less radiation exposure to normal tissues, proton therapy also lowers the risk of side effects and secondary, radiation-induced cancers. Additionally, proton therapy can treat recurrent cancers and children with cancer. This advanced technology: • Targets and destroys tumors with pinpoint accuracy • Provides better protection to surrounding healthy tissues • Requires less radiation • Leaves virtually no exit dose; i.e., little to no
    [Show full text]
  • Radiation Therapy and Breast Cancer
    The Breast Center Smilow Cancer Hospital 20 York Street, North Pavilion New Haven, CT 06510 Phone: (203) 200-2328 Fax: (203) 200-2075 RADIATION THERAPY Radiation therapy is a local treatment using high energy rays (like x-rays) to kill cancer cells or shrink tumors. It has an important role in treating all stages of breast cancer because it is so effective and safe. Radiation therapy can be used to kill any cancer cells that remain in the breast, on the chest wall or in the under arm area particularly after breast conserving treatment. Nearly all patients who undergo a partial mastectomy as their primary surgical treatment will require evaluation by the radiation oncologists. They are the cancer doctors who prescribe radiation and oversee your radiation treatment. Radiation therapy after surgery has been shown to statistically significantly decrease the risk of a local, or in breast, recurrence. Research has now shown that selected women over the age of 70 may sometimes safely skip this treatment, but the decision is usually made in consultation with the radiation oncologist. Radiation may NOT be a good choice for you if: • you have previously been radiated in that same area • you have a connective tissue disease such as scleroderma or lupus • you are pregnant • you are not willing or able to commit to the daily schedule it requires Radiation therapy may be required after mastectomy if there are features associated with a high risk of recurrence. These may include: • a cancer 5 cm or larger • the presence of lymphovascular invasion • evidence of lymph node involvement • skin involvement • a positive margin or invasion into the chest wall There are currently two types of radiation treatments.
    [Show full text]
  • Introduction to Radiation Oncology
    An Overview of Radiation Therapy for Health Care Professionals American Society for Radiation Oncology Introduction Radiation has been an effective tool for treating cancer for more than 100 years More than 60 percent of patients diagnosed with cancer will receive radiation therapy as part of their treatment Radiation oncologists are cancer specialists who manage the care of cancer patients with radiation for Patient being treated with modern either cure or palliation radiation therapy equipment. Overview What is the physical and biological basis for radiation What are the clinical applications of radiation in the management of cancer What is the process for treatment Simulation Treatment planning Delivery of radiation What types of radiation are available Summary What Is the Biologic Basis for Radiation Therapy? Radiation therapy works by damaging the DNA of cells and destroys their ability to reproduce Both normal and cancer cells can be affected by radiation, but cancer cells have generally impaired ability to repair this damage, leading to cell death All tissues have a tolerance level, or maximum dose, beyond which irreparable damage may occur Fractionation: A Basic Radiobiologic Principle Fractionation, or dividing the total dose into small daily fractions over several weeks, takes advantage of differential repair abilities of normal and malignant tissues Fractionation spares normal tissue through repair and repopulation while increasing damage to tumor cells through redistribution and reoxygenation The Four R’s of
    [Show full text]