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 (ACTBM) 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 (ACTBM) was characterized employing 18FDG-PET. Dosimetric parameters on dose–volume histograms were correlated to nadirs with generalized linear modeling. Results: ACTBM mean dose was significantly correlated to white blood cell (β = −1.338; 95%CI: −2.455/−0.221; p = 0.020), absolute neutrophil count (β = −1.651; 95%CI: −3.284/−0.183; p = 0.048), and platelets (β = −0.031; 95%CI: −0.057/−0.004; p = 0.024) nadirs. Other dosimetric parameters were found to be correlated (ACTBM-V10,-V20,-V30and-V40). Conclusions: 18FDG-PET is able to define active bone marrow and may predict for decreased blood cells count nadirs.