Comparative Analysis of Dosimetry: IMRT versus 3DCRT in Left-Sided Breast Cancer Patients with Considering Some Organs in Out - of – Field Borders

Shaimaa G Ghazy,1 Mostafa A Abdel-Maksoud,2 Ibrahim A Saleh,3 Mohamed A El-Tayeb,2 Amr A Elsaid,4 Metwally A Kotb,5 Diana A Al-Sherif,6 Heba S Ramadan,5 Ahmed Elwahsh,7,8 Ahmed M Hussein,9,10 Ahmad S Kodous11,12 1Radiation Therapy Department, Armed Forces Medical Complex, Alexandria, Egypt; 2Botany and Microbiology Department- College of Science- King Saud University, Riyadh, Saudi Arabia; 3Faculty of Science, Zarqa University, Zarqa, 13110, Jordan; 4Oncology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt; 5Medical Biophysics Department, Medical Research Institute, Alexandria University, Alexandria, Egypt; 6Applied Medical Science Faculty, Sixth October University, Sixth October, Giza, Egypt; 7Central Radiology Institute, Kepler University Hospital GmbH, Linz, Austria; 8Department of Molecular and Translational Medicine, Division of Biology and Genetics, University of Brescia, Brescia, Italy; 9Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, 1090, Austria; 10Zoology Department, Faculty of Science, Al Azhar University, Assiut, Egypt; 11Pharmacology Department, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College & Hospitals, Chennai, TN, India; 12Radiation Biology Department, National Center for Radiation Research and Technology (NCRRT), Egyptian Atomic Energy Authority (EAEA), Cairo, EgyptCorrespondence: Ahmad S Kodous; Ahmed M Hussein, Email [email protected]; [email protected]: The local management approach for node-positive breast cancer has undergone substantial evolution. Consequently, there exists a pressing need to enhance our treatment strategies by placing greater emphasis on planning and dosimetric factors, given the availability of more conformal techniques and delineation criteria, achieving optimal goals of radiotherapy treatment. The primary aim of this article is to discuss how the extent of regional nodal coverage influences the choice between IMRT and 3D radiation therapy for patients.Patients and Methods: A total of 15 patients diagnosed with left breast cancer with disease involved lymph nodes were included in this study. Delivering the recommended dose required the use of a linear accelerator (LINAC) with photon beams energy of 6 mega voltage (6MV). Each patient had full breast radiation using two planning procedures: intensity-modulated radiotherapy (IMRT) and three-dimensional radiotherapy (3D conformal). Following the guidelines set forth by the Radiation Therapy Oncology Group (RTOG), the planned treatment coverage was carefully designed to fall between 95% and 107% of the recommended dose. Additionally, Dose Volume Histograms (DVHs) were generated the dose distribution within these anatomical contours.Results and Conclusion: The DVH parameters were subjected to a comparative analysis, focusing on the doses absorbed by both Organs at Risk (OARs) and the Planning Target Volume (PTV). The findings suggest that low doses in IMRT plan might raise the risk of adverse oncological outcomes or potentially result in an increased incidence of subsequent malignancies. Consequently, the adoption of inverse IMRT remains limited, and the decision to opt for this therapy should be reserved for situations where it is genuinely necessary to uphold a satisfactory quality of life. Additionally, this approach helps in reducing the likelihood of developing thyroid problems and mitigates the risk of injuries to the supraclavicular area and the proximal head of the humerus bone.Keywords: radiotherapy, LINAC, RTOG, breast cancer, photon exposure and secondary cancer risk