Dosimetric predictors of acute hematologic toxicity in cervical cancer patients treated with concurrent cisplatin and intensity-modulated pelvic radiotherapy

Purpose: To identify dosimetric parameters associated with acute hematologic toxicity (HT) and chemotherapy delivery in cervical cancer patients undergoing concurrent chemotherapy and intensity-modulated pelvic radiotherapy. Methods and Materials: We analyzed 37 cervical cancer patients receiving concurrent cisplatin (40 mg/m 2/wk) and intensity-modulated pelvic radiotherapy. Pelvic bone marrow (BM) was contoured for each patient and divided into three subsites: lumbosacral spine, ilium, and lower pelvis. The volume of each region receiving 10, 20, 30, and ≥40 Gy (V 10, V 20, V 30, and V 40, respectively) was calculated. HT was graded according to the Radiation Therapy Oncology Group system. Multivariate regression models were used to test associations between dosimetric parameters and HT and chemotherapy delivery. Results: Increased pelvic BM V 10 (BM-V 10) was associated with an increased Grade 2 or worse leukopenia and neutropenia (odds ratio [OR], 2.09; 95% confidence interval [CI], 1.24–3.53; p = 0.006; and OR, 1.41; 95% CI, 1.02–1.94; p = 0.037, respectively). Patients with BM-V 10 ≥90% had higher rates of Grade 2 or worse leukopenia and neutropenia than did patients with BM-V 10