1. Comparison Of Two Contouring Methods Of Bone Marrow On CT & Correlation With Hematological Toxicities (HT) In Non Bone Marrow Sparing Pelvic IMRT (NBM-IMRT) With Concurrent Cisplatin For Cervical Cancer R. Krishnatry*, U. M. Mahantshetty, S. Chaudhri, A. Kanujia, R. Engineer, S. Chopra, S. K. Shrivastava, Tata Memoiral Hosptial, Mumbai, India Two sets Vs. In cervical cancer patients treated with Non Bone Marrow sparing IMRT (NBM-IMRT) & concurrent cisplatin. Compare the volumes & Dose volume parameters (DVH) for contours of bone marrow using two methods of contouring on CT scan Correlation of DVH parameters with > grade 2 (RTOG) Hematological Toxicity (HT). 47 patients prospectively enrolled & treated in pelvic IMRT (NBM-IMRT) and concurrent cisplatinum in Phase II trial (NCT00193804). The planning CT scans contoured for pelvic bone marrow in two sets: (Fig 1) - Whole bone using auto-segmentation (WB) - Free hand (FH) inner cavity of bone Various sub-volumes were made in each set as sacrum; ilium; ischium; Lower Pelvis (pubes, ischia, acetabula, & proximal femora); lumbosacral spine; sacrum & whole pelvis (all sub- volumes as one) Volume & DVH parameters compared for two sets using paired t test Purpose / Objectives Conclusion Materials / Methods Results Free Hand bone marrow cavity volume is a better surrogate of active bone marrow on CT images both in terms of volumes and DVH parameters. Only Free hand Whole Pelvis V40 >40% correlated with higher than grade 2 HT It may be an important marker of high toxicity especially when V10 <90%. Figure 1. Bone Marrow Contouring using Whole Bone & Free Hand Technique And various sub-volumes in each. Number of Patients47 Age (years) - Mean (Range)49.2 (33-65) StageIIB IMRT dose50Gy/25#/5Weeks Brachy Dose7Gy x 5 # Transfusion - n(%) Pre-treatment [whole blood only] On treatment Whole blood G-CCF Platelet 5(11%) 11 (24.7%) 5 (10.6%) 2(4.7%) Chemotherapy (number) Chemotherapy agent / Dose Mean no of cycles 47/47 Cisplatin / 40 mg/m2 4.6 Mean PTV volume (range) cc1440.37 (974-2352) cc Table 1: General Characteristics Comparison of volume Whole bone (W) Mean (Range) cc Bone cavity free hand (F) Mean (Range) cc F/Wx100 (%) Sacrum Ilium Ischium Lower Pelvis LS Spine Whole Pelvis 147 (105-218) 265 (200-377) 220 (139-369) 417 (295-557) 230 (150-322) 925 (690-1268) 31.4 (18-50) 82.65 (53-139) 49.4 (27-81) 105.9 (70-164) 47.3 (26-77) 240 (170-372) 21.08% 30.94% 22.27% 25.18% 20.43% 25.95% Table 2: Comparison of Volumes SPECT IMRT [1] Mean Anal Ca, Mell [2] Mean (SD) Cervix, Mell [3] Mean (SD) Current, Whole bone Mean (SD) Current, Free hand Mean (SD) Whole pelvis V10 V20 V30 V40 100 88 66 23 85(15) 75(17) 56(19) 32(17) 91(3.6) 74(6.1) 53(7.5) 28(10.3) 88(5.18) 79.6(5.2) 62.9(6.5) 40(0.45) 86.5 (6.8) 77.5 (6.2) 62.5 (6.5) 40.5 (8.4) Table 3: Comparison of whole pelvis doses in various studies. Figure 2: DVH of a Patient Developing Grade 3 Neutropenia Significant difference between DVH parameters of two sets (p<0.05) for all sub-volumes. Leucopenia, neutropenia, anemia, and thrombocytopenia > grade 2 was seen in 53%, 29.8%, 65.9%, and 10.6%, respectively. On both univariate and multivariate analysis only FH whole pelvis V 40 ≥40% correlated with >grade 2 leucopenia (Whitney U, p=0.026) and neutropenia (p=0.05) with OR 4 (CI, 1.166 Y 13.728 ;P =0.028). References 1. Roeske et al. Incorp of SPECT bone marrow. Radiother Oncol 2005;77:11-7 2. Mell et al Association between….IJOBP 2008;70:1431-7. 3. Mell et al Dosimetric predic…. IJROBP 2006; 66 (5):1356–1365. Hematological parameters during treatment analyzed for > grade 2 (RTOG) HT as significant toxicity & correlated with DVH parameters using log regression analysis Article in press in IJGC. Contact : krishnatry@gmail.com drumeshm@gmail.com Poster number 2554; E-01