Abstract
BackgroundTo quantify the dosimetric parameters of different bone marrow sparing strategies and to determine the optimal strategy for cervical cancer patients undergoing postoperative intensity-modulated radiotherapy (IMRT).MethodsFifteen patients with cervical cancer were selected for analysis. The planning target volume (PTV) and the organs at risks (OAR) including small bowel, bladder, rectum, femoral heads, os coxae (OC), lumbosacral spine (LS) and bone marrow (BM) were contoured. For each patient, four IMRT plans with different strategies were generated, including one plan without BM as the dose-volume constraint, namely IMRT (N) plan, and three bone marrow sparing (BMS-IMRT) plans. The three BMS-IMRT plans used the BM, OC, OC and LS respectively, as the BM OAR, namely as IMRT (BM), IMRT (OC) and IMRT (OC + LS) plans. Dose volumes for the target and the OARs were compared using analysis of variance (ANOVA).ResultsCompared with IMRT (N) plans, the dose to the small bowel, bladder, rectum and femoral heads showed no increase in the three BMS-IMRT plans. However, the irradiated dose to BM, OC and LS significantly decreased. In particular, the mean dose of BM, OC and LS decreased by about 5Gy (p < 0.05) in IMRT (BM) plans while the average volume receiving ≥20, ≥30, ≥40Gy decreased by 7.1–24.2%. The LS volume receiving 40Gy showed the highest decrease (about 31.2%, p < 0.05) in IMRT (OC + LS) plans. On the other hand, in comparison with IMRT (BM), IMRT (OC) reduced the dose volume of to the OC, but increased the dose to LS while IMRT (OC + LS) plans reduced both the OC and the LS volume at all dose levels. Specifically, the V20 of OC and LS in the IMRT (OC + LS) plan decreased by 11.5 and 11.2%, respectively.ConclusionBy introducing the os coxae and lumbosacral spine as the dose–volume constraints, the IMRT plans exhibited the best sparing of the bone marrow without compromising the dose to surrounding normal structures. Therefore, we recommend adding the os coxae and lumbosacral spine as the BM OAR in such plans.
Highlights
To quantify the dosimetric parameters of different bone marrow sparing strategies and to determine the optimal strategy for cervical cancer patients undergoing postoperative intensity-modulated radiotherapy (IMRT)
The planning target volume (PTV) planning objectives were achieved with four different dose limitation strategies and all plans were normalized to cover 95% of the PTV with ≥100% of the prescribed dose
In terms of conformity index (CI) and homogeneity index (HI), IMRT (BM) plan and IMRT (N) plan showed the slightly better conformity and homogeneity than did in IMRT (OC + lumbosacral spine (LS)) plans, but they resulted in a greater dose to the bone marrow
Summary
To quantify the dosimetric parameters of different bone marrow sparing strategies and to determine the optimal strategy for cervical cancer patients undergoing postoperative intensity-modulated radiotherapy (IMRT). Adjuvant pelvic radiotherapy with concurrent chemotherapy is the standard treatment approach or cervical cancer patients who have previously undergone hysterectomy [1]. Studies have shown the advantages of pelvic intensitymodulated radiation therapy (IMRT), including better dosimetric distribution, relatively lower irradiation dose to normal tissues and fewer acute side effects, compared with conventional forward planning techniques [4, 5]. During pelvic IMRT, a large volume of BM is irradiated, Bao et al Radiation Oncology (2019) 14:118 along with other critical normal tissues such as the small bowel, bladder, rectum and femoral heads, and the irradiation is unavoidable. An effective planning strategy to limit bone marrow irradiation and limit the incidence of HT is needed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
