Association Between Bone Marrow Dosimetric Parameters and Acute Hematologic Toxicity in Cervical Cancer Patients Undergoing Concurrent Chemoradiotherapy: Comparison of Three-Dimensional Conformal Radiotherapy and Intensity-Modulated Radiation Therapy

OBJECTIVE: We compare different dosimetric parameters in cervical cancer patients receiving concurrent chemotherapy and three-dimensional conformal radiotherapy (3DCRT) or intensity-modulated radiation therapy (IMRT) and explore the incidence of hematological toxicity (HT) in these patients. METHODS: Twenty patients receiving 3DCRT or IMRT and 4 weekly doses of cisplatin (25 mg/m(2)/w) were studied. The volumes of bone marrow receiving 10, 20, 30, 40 and 50 Gy or greater (V10, V20, V30, V40, and V50, respectively) were calculated. The HT was graded according to the guidelines of the Radiation Therapy Oncology Group system. The associations between dosimetric parameters and HT and chemotherapy delivery were analyzed. RESULTS: The bone marrows V30, V40, and V50 were lower in the IMRT group than in the 3DCRT group (62.93% vs 76.91%, 31.36% vs 39.60%, and 9.79% vs 15.44%, respectively). No statistical difference was observed for both V10 and V20. Acute hematologic toxicity occurred in both groups but was more frequent in the 3DCRT group. The percentage of patients with grade 2 and worse leukopenia and neutropenia was 90% and 80% in the 3DCRT group, whereas it was 80% and 40% in the IMRT group. The median nadir of white blood cells and the absolute neutrophil count were significantly lower in the 3DCRT group than in the IMRT group (1.96 × 10(9) vs 2.72 × 10(9) and 1.09 × 10(9) vs 1.86 × 10(9), respectively). CONCLUSION: The IMRT reduced the volume of bone marrow irradiated at the higher doses and the incidence and severity of acute hematologic toxicity in cervical cancer patients undergoing concurrent chemoradiotherapy.