Dose to Pelvic Bone Marrow Defined with FDG-PET Predicts for Hematologic Nadirs in Anal Cancer Patients Treated with Concurrent Chemo-radiation.

Purpose: To investigate whether irradiated volume of pelvic active bone marrow ((BM)-B-ACT) may predict decreased blood cells nadirs in anal cancer patients undergoing concurrent chemo-radiation. Methods: Forty-four patients were analyzed and pelvic active bone marrow (BM)-B-ACT) was characterized employing (18)FDG-PET. Dosimetric parameters on dose-volume histograms were correlated to nadirs with generalized linear modeling. Results: (BM)-B-ACT mean dose was significantly correlated to white blood cell (beta= -1.338; 95%CI: -2.455/-0.221; p=0.020), absolute neutrophil count (beta=-1.651; 95%CI: -3.284/-0.183; p = 0.048), and platelets (beta= -0.031; 95%CI: -0.057/-0.004; p = 0.024) nadirs. Other dosimetric parameters were found to be correlated ((BM)-B-ACT-V-10,V--V-20,V--V-30 and-V-40). Conclusions: (18)FDG-PET is able to define active bone marrow and may predict for decreased blood cells count nadirs.