en Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;"><span style="font-size:10pt"><span style="text-justify:newspaper"><span style="text-kashida-space:50%"><span style="line-height:119%"><span style="font-family:Calibri"><span style="color:black"><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Background:</span></span></span></span></span></span> <span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">To investigate the effect of radiation dose to thoracic vertebrae (TV) on the development of hematologic toxicity in esophageal cancer patients treated with intensity-modulated radiotherapy. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Materials and Methods:</span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US"> We identified 28 patients with esophageal cancer treated with chemoradiotherapy between 2014-2021.Vertebral volumes receiving 5-50 Gy (TV5-50) and the mean vertebral and thoracic blood pool dose were collected from the dose-volume-histogram. Complete blood cell counts were analyzed and hematologic toxicities were graded according to the Common Terminology Criteria for Adverse Events version5.0 (CTCAE v5.0). </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Results: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">TV50 was negatively linearly associated with mean lymphocyte nadir by percentage. TV20 was negatively linearly associated with mean platelet nadir by cc. Planning Target Volume (PTV) length was negatively linearly associated with mean hemoglobin nadir. The optimal threshold dose values for avoiding grade &ge;4 lymphopenia was TV40 of <22.3%, TV50 of <9.09%, mean thoracic blood pool dose of < 16.9 Gy, PTV volume of <652 cc and PTV length of <16.7 cm. The optimal threshold dose values for avoiding grade &ge;3 leukopenia were TV10 of <47.6%, TV20&nbsp; of <39.7%, TV30 of< 34.69%,and mean vertebral dose of <17.7Gy. </span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="color:#1f497d"><span style="font-style:italic"><span style="font-weight:bold"><span style="language:en-US">Conclusion: </span></span></span></span></span></span><span lang="en-US" style="font-size:9.0pt"><span style="font-family:Calibri"><span style="language:en-US">This study demonstrated a statistically significant negative correlation between vertebral doses and hematologic parameters. The optimal threshold dose values for avoiding grade &ge;3 leukopenia were TV10 of <47.6% and mean vertebral dose of <17.7Gy.</span></span></span></span></span></span></span></span></span></div> Esophageal neoplasms, chemoradiotherapy, hematologic toxicity, complete blood cell counts, dosimetry parameter. 1043 1049 http://ijrr.com/browse.php?a_code=A-10-1-1433&slc_lang=en&sid=1 C. Barlas dr.cerencicibiyik@gmail.com 7900319475328460032507 7900319475328460032507 Yes Department of Radiation Oncology, Sivas Numune Hospital, Sivas, Turkey T.K. Çatal 7900319475328460032508 7900319475328460032508 No Department of Radiation Oncology, Kahramanmaraş Necip Fazil City Hospital, Kahramanmaraş, Turkey H.C. Yıldırım 7900319475328460032509 7900319475328460032509 No Department of Radiation Oncology, Istanbul University- Cerrahpaşa, Cerrahpaşa Faculty of Medicine, Istanbul, Turkey E.S. Akovalı 7900319475328460032510 7900319475328460032510 No Department of Radiation Oncology, Sakarya Training and Research Hospital, Sakarya, Turkey S.Ç. Karaçam 7900319475328460032511 7900319475328460032511 No Istanbul University-Cerrahpaşa, Vocational School of Health Services, Radiotherapy Program, Turkey Ş.A. Ergen 7900319475328460032512 7900319475328460032512 No Department of Radiation Oncology, Istanbul University- Cerrahpaşa, Cerrahpaşa Faculty of Medicine, Istanbul, Turkey D.Ç. Öksüz 7900319475328460032513 7900319475328460032513 No Department of Radiation Oncology, Istanbul University- Cerrahpaşa, Cerrahpaşa Faculty of Medicine, Istanbul, Turkey