PBMS-IMRT Reduces The Incidence Of The Hematologic Toxicity Of Patients With Cervical Cancer Receiving Concurrent Chemoradiotherapy:A Single-center Prospective Randomized Controlled Trail

Objective: A prospective study to identify the correlation between dosimetric parameters and grade 2 or higher hematological toxicity(HT2+)in patients with cervical cancer treated with concurrent chemoradiotherapy,and to investigate the ability of Pelvic Bone Marrow Sparing Intensity Modulated Radiotherapy(PBMS-IMRT)to reduce the irradiation of pelvic bone marrow(PBM).Methods: A total of 164 patients with cervical cancer undergoing concurrent cisplatin and pelvic radiotherapy were enrolled and divided randomly into two cohorts: the PBMS group(n = 82)with the addition of a PBMS constraint and the control group(n = 82)without any dose constraint.Pelvic bone and marrow were contoured and divided into two subsites: hip bone(HIP)and lumbosacral spine(LSS).The volume of receiving 10,20,30 and > 40 Gy(V10,V20,V30 and V40,respectively)was calculated.Multivariate regression models were used to test associations between dosimetric parameters and HT2+.Receiver operating characteristic curves were used to derive optimal dosimetric planning constraints.Results: The percentage of patients with HT2+ during treatment in PBMS group and control group was significantly different(p <0.05).PB V40>28% were more likely to experience HT2+(OR,3.392,p = 0.0087).Dosimetric parameters of LSS have stronger associations with HT2+ than other subsites.The patients with LSS V10>84% and LSS mean >38.94 Gy were more likely to experience HT2+(OR=5.05,p = 0.0029;OR =3.325,p = 0.041,respectively).Conclusion: PBMS-IMRT significantly reduces radiation dose to the PBM and the incidence of hematotoxicity events in cervical cancer patients with concurrent chemoradiotherapy.Efforts to maintain LSS V10 ? 84%,LSS Mean? 39 Gy and PBM V40 ? 28% simultaneously may reduce the risk of HT2+.