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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. Two sets Vs.
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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 Two sets Vs. R. Krishnatry*,U. M. Mahantshetty, S. Chaudhri, A. Kanujia, R. Engineer, S. Chopra, S. K. Shrivastava, Tata Memoiral Hosptial, Mumbai, India Poster number 2554; E-01 Purpose / Objectives • 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). Article in press in IJGC. Contact : krishnatry@gmail.com drumeshm@gmail.com Materials / Methods • 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 Figure 1. Bone Marrow Contouring using Whole Bone & Free Hand Technique And various sub-volumes in each. • Hematological parameters during treatment analyzed for > grade 2 (RTOG) HT as significant toxicity & correlated with DVH parameters using log regression analysis Results Table 3: Comparison of whole pelvis doses in various studies. Table 1: General Characteristics Table 2: Comparison of Volumes 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 V40 ≥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). Conclusion • 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%. 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.