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 (ACT BM) 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 (ACT BM) was characterized employing 18 FDG-PET. Dosimetric parameters on dose-volume histograms were correlated to nadirs with generalized linear modeling.

RESULTS: ACT BM 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 (ACT BM-V10, -V20, -V30 and-V40 ).

CONCLUSIONS: 18 FDG-PET is able to define active bone marrow and may predict for decreased blood cells count nadirs.