2026 ASTRO Radiation and Cancer Biology Study Guide

The ASTRO Radiation and Cancer Biology Study Guide is not meant to be used as a curriculum guide and should be just one of multiple resources to study for the exam.

In recognition of the critical need to develop new ways to promote education regarding the biologic basis of radiotherapy, the Education Committee of ASTRO appointed a subcommittee to develop a dynamic web-based educational resource for radiation oncologists studying radiation and cancer biology. The ASTRO Radiation and Cancer Biology Study Guide is the product of these efforts. This study guide was created specifically to stimulate active learning.

It is our suggestion that users of this study guide answer all of the questions in each section and then review the correct answers and explanations. It is anticipated that this approach will lead to a more complete understanding of each topic. References have been included whenever possible along with a hyperlink to the article abstract for topics that may not be comprehensively addressed in the major radiation biology textbooks cited as a primary reference in the 2026 Study Guide released by the American Board of Radiology (ABR). It should be noted that for the selection of references an emphasis was placed on recent review articles that provide current and comprehensive information on a particular subject; however, key historical references are also cited. Finally, although this is not an exhaustive resource for preparation for the ABR Radiation and Cancer Biology written examination, questions and answers were cross referenced with the ABR study guide to align with this content.

Radiation and cancer biology are dynamic fields with new results published daily in the scientific literature. The goal for radiation oncologists is to acquire a solid base of knowledge in radiation and cancer biology during training and to subsequently build upon that foundation throughout their career by regular reading of the scientific literature as well as by attendance at seminars and scientific conferences. The ASTRO Radiation and Cancer Biology Study Guide is designed to help radiation oncologists achieve this goal. It is our hope that providing radiation oncologists in-training with a firm foundation underlying the biologic principles of therapeutic radiation will ultimately yield more effective radiotherapeutic treatment techniques as well as improved clinical outcomes for patients.

Course summary
Course opens: 
07/02/2025
Course expires: 
01/18/2027
Cost:
$0.00
Rating: 
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Note on Protein and Gene Nomenclature
The 2026 ASTRO Radiation and Cancer Biology Study Guide uses the notation system for the name of each gene and protein encoded by that gene that was developed by the HUGO Gene Nomenclature Committee. The details for that system can be found at http://www.gene.ucl.ac.uk/nomenclature/. The guidelines for this sytem stipulate that gene symbols are italicized and designated by upper-case Latin letters or by a combination of upper-case letters and Arabic numerals. The protein encoded by the gene is given the same symbol as the gene, except that the letters are not italicized. Thus, the symbol for the gene mutated in people with the disease ataxia telangiectasia is ATM and the protein encoded by that gene is written as ATM. It should be noted that although HUGO is widely used in scientific journals and textbooks, this system is rarely used for some proteins and genes. For these genes/proteins, the common symbol has been used in the study guide, but the HUGO symbol is provided in parentheses the first time that the gene/protein is written in the question. For example, p53 is used in the study guide rather than the official HUGO symbol for this gene, which is TP53. This is noted by indicating p53 (TP53) in the question or explanation.

This study guide is comprised of the 32 chapters listed below. Once you have registered, click the Take Course tab and use the left side navigation in the course to access each chapter.

Radiobiology Study Guide Topics

1. Interaction of Radiation with Matter17. Clinically Relevant Normal Tissue Responses to Radiation
2. Molecular Mechanisms of DNA Damage18. Mechanisms of Normal Tissue Radiation Responses
3. Molecular Mechanisms of DNA Repair19. Therapeutic Ratio
4.Chromosome and Chromatid Damage20. Time, Dose, Fractionation
5. Mechanisms of Cell Death21. Brachytherapy
6. Cell and Tissue Survival Assays22. Radiobiological Aspects of Alternative Dose Delivery Systems
7. Models of Cell Survival23. Chemotherapeutic Agents and Radiation Therapy
8. Linear Energy Transfer24. Radiosensitizers, Radioprotectors and Bioreductive Drugs
9. Modifiers of Cell Survival: Oxygen Effect  25. Hyperthermia
10. Modifiers of Cell Survival: Repair26. Radiation Carcinogenesis
11.Solid Tumor Assay Systems27. Heritable Effects of Radiation
12.Tumor Microenvironment28. Radiation Effects in the Developing Embryo and Fetus
13. Cell and Tissue Kinetics29. Radiation Protection
14. Molecular Signaling30. Molecular Techniques used in Radiation and Cancer Biology
15. Cancer31. Molecular Imaging
16. Total Body Irradiation32. Cancer Immunology

We would like to thank each of the Associate Editors and contributors who wrote and carefully reviewed the questions, explanations, and references. Most importantly, we thank Dr. Barry Rosenstein for his commitment to this subcommittee via the initiation of this project. Without the assistance and volunteerism of these individuals, production of the 2026 ASTRO Radiation and Cancer Biology Study Guide would have not been possible.

Editor-in-Chief (2022‒2026): Kathryn Huber, MD, PhD, Tufts University School of Medicine

Associate Editors

  • Ranjit Bindra, MD, PhD, Yale University
  • Deborah Citrin, MD, FASTRO, National Cancer Institute
  • Andrew Kopecky, MD, PhD, Brown University Health
  • Sunil Krishnan, MD, FASTRO, University of Texas Health Science Center at Houston
  • Yaacov Lawrence, MD, MRCP, FASTRO, Sheba Medical Center
  • David Mayhew, MD, PhD, Tufts Medical Center
  • Kent Mouw, MD, PhD, Dana-Farber/Brigham and Women’s Cancer Center
  • Thomas Mullen, MD, PhD, Radiation Oncology Group Consultants
  • Paul Rava, MD, PhD, Rhode Island Hospital
  • Naoyuki Saito, MD, PhD, Indiana University School of Medicine
  • Stephen Sapareto, PhD, Banner MD Anderson Cancer Center
  • Dorthe Schaue, PhD, UCLA
  • Daniel Schmidt, MD, PhD, Beth Israel Deaconess Medical Center
  • Zhiyuan Shen, PhD, Rutgers Cancer Institute of New Jersey
  • Alex Spektor, MD, PhD, Dana-Farber Cancer Institute
  • Benjamin Stinson, MD, Dana-Farber Cancer Institute
  • Gayle Woloschak, MD, PhD, FASTRO, Northwestern University Medical School (Editor-in-Chief 2019‒2022)

Price

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Participants using ASTRO Academy activities to satisfy the requirement of a Continuing Certification (MOC) program should verify the credit number and type and availability dates of any activity before making a purchase. No refunds, extensions, or substitutions will be made for participants who have purchased activities that do not align with their MOC requirement.

The activity and its materials will only be available on the ASTRO website until January 18, 2027, regardless of purchase date. At the expiration of the activity, participants will no longer have access to the activity or its materials. ASTRO reserves the right to remove an activity before its expiration date.

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