Longitudinal study of acute haematologic toxicity in cervical cancer patients treated with chemoradiotherapy.

Introduction: Acute hematologic toxicity (HT) limits optimal delivery of concurrent chemoradiotherapy (CRT) for patients with pelvic malignancies. We tested the hypothesis that pelvic bone marrow (PBM) dose-volume metrics were associated with weekly reductions in peripheral blood cell counts in cervical cancer patients undergoing CRT.

Methods: We included 102 cervical cancer patients treated with concurrent cisplatin (40 mg/m(2) /week) and pelvic radiotherapy treated at three US centres. No patient received granulocyte-monocyte colony stimulating factor (GM-CSF) or platelet transfusions. Using linear-mixed effects modelling, we analysed weekly reductions in log-transformed peripheral blood cell counts as a function of time (weeks), mean PBM dose and the PBM volume receiving ≥10 Gy (V(10)), 20 Gy (V(20)), 30 Gy (V(30)) and 40 Gy (V(40)).

Results: Increases in mean PBM radiation dose, V(20), V(30) and V(40) were all significantly associated with a greater weekly reduction in white blood cell (WBC) and absolute neutrophil counts (ANCs). We estimated that with every 1 Gy increase in mean PBM dose, ln(ANC) was reduced by 9.6/μL per week (95% confidence interval, 1.9-17.3, P = 0.015). Subregion analysis also identified significant associations between weekly reductions in ln(WBC) and ln(ANC) within lumbosacral spine, ischium and proximal femora, as opposed to ilium.

Conclusions: PBM radiation dose-volume metrics are significantly associated with weekly reductions in peripheral blood cell counts in cervical cancer patients undergoing CRT, particularly within the lower pelvis and lumbosacral spine.