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

Abstract

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-V_10,-V_20,-V₃₀and-V₄₀).

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

Keywords: Anal cancer; Bone marrow; Concomitant radiochemotherapy; Hematologic toxicity; IMRT; PET; Radiotherapy.