HA spacer and CTV-rectum space
toxicity, CRS, prostate
PROSTATE
The mean injected HA was 16 ± 4 [range 8–24] cmMean CTV-Rectum Space (CRS) and HA thickness in MR0, MR1,MR2 and MR3HA caused a significant increase in CRS from MR0 to MR1/MR2/MR3. A CRS > 10 mm in the prostate base, middle and apex levels was achieved in 35 patients (67%) in MR1, 23 patients (44%) in MR2 and 26 patients (50%) in MR3. Even without HA, six patients (12%) had a CRS > 10 mm in all three levels due to anatomical variations. From MR0 to MR1, the CRS increased by 114%. CRS decreased by 19% in MR2 and 17% in MR3 compared to MR1 in the middle level. Further, HA thickness decreased by 28% in MR2 and 32% in MR3 compared to MR1 in the middle level. See Additional file For the CRS variation with V90% combined with grade 2 and 3 rectal toxicity see Additional file 