Comparison of IMRT Plans with and Without Bone Marrow Sparing For the Treatment of Cervical Cancer

The present study aimed to compare plans with Bone Marrow sparing (BM-IMRT) and without Bone Marrow Sparing (N-IMRT).
Fifteen cases of cervical cancer cases were selected for retrospective study. All the cases were previously treated with normal IMRT. For this study, plans with BM-IMRT were created again for all patients following RTOG guidelines. The prescribed dose of 50Gy in 25 fractions was given. The plan having coverage of 95% of PTV receiving 95% of the prescribed dose was accepted. The plans were compared based on PTV coverage (dose to 2%, 98% of target); constraints of OARs (Organs at Risk) were the volume of 40% < 40Gy for normal bladder and rectum (volume receiving dose 5Gy) V5<95%, V10<80%, V20<60%, V30<50% and V40<35% respectively for Bone marrow and lowest possible doses to bowel were given for planning criteria. Apart from this, HI, CI and R50% were also calculated concerning PTV coverage to analyze plan quality.
There was a statistical difference in P-values of D2, D98, TV95, HI, R50% but the actual difference is less than 2%. In the case of OARs, there were also significant differences in statistical as well longitudinal in values of V10, V20, V30 and V40 of Bone Marrow (P<0.01) and there was only statistical differences (p<0.05) at V50 of bladder and rectum.
Without scarifying dose coverage for planning target volume, bone marrow can be spared while treating cervical cancer patients using IMRT technique with bone marrow as an extra constraint.