RESUMO
BACKGROUND: FLT-PET/CT can accurately identify and locate functional bone marrow (FBM) with hematopoietic capability, the FBM were divided into two levels as FBM1 (strongest hemopoietic ability region)and FBM2 (moderate hemopoietic ability region) via FLT-PET/CT. The purpose of this study was to explore the relationship between dose-volume parameters of pelvic FBM and hematologic toxicity (HT) during radiotherapy with or without concurrent chemotherapy for uterine cervical/endometrial cancer. METHODS: From December 2016 to September 2021, ninety-seven uterine cervical/endometrial cancer patients received intensity-modulated radiation therapy were prospectively recruited in this single-arm, prospective, phase II trial. Blood counts were reviewed weekly during radiotherapy. Single- and multifactor regression methods were used to analyze the relationships between dose-volume parameters of FBM1/2 and grade ≥ 2 HT. ROC curves were used to determine the cutoff values for the dose-volume parameters of FBM1/2. RESULTS: The incidence of grade ≥ 2 leukopenia, neutropenia, thrombocytopenia and anemia in patients during radiotherapy was 63.9%, 45.4%, 19.6% and 38.8% respectively, and the median occurrence time was the 29th, 42th, 35th and 31th day, respectively. Multivariate regression analysis showed that the Dmax of FBM1 was significantly related to grade ≥ 2 leukopenia (OR = 1.277 95% CI 1.067-1.528, P = 0.008), Dmean of FBM2 was significantly related to grade ≥ 2 thrombocytopenia (OR = 1.262 95% CI 1.066-1.494, P = 0.007), and V10 of FBM1 was significantly related to grade ≥ 2 anemia (OR = 1.198 95% CI 1.003-1.431, P = 0.046). The incidence of grade ≥ 2 leukopenia for patients with FBM1 Dmax < 53 Gy was lower than that for patients with FBM1 Dmax ≥ 53 Gy (53.4% vs. 95.8%, P < 0.001). The incidence of grade ≥ 2 thrombocytopenia in patients with FBM2 Dmean < 33 Gy was lower than that in patients with FBM2 Dmean ≥ 33 Gy (0 vs. 28.4%, P < 0.001). The incidence of grade ≥ 2 anemia for patients with FBM1 V10 < 95% was lower than that in patients with FBM1 V10 ≥ 95% (24.4% vs. 57.1%, P = 0.003). CONCLUSIONS: Grade ≥ 2 HT usually occurs in the 4th week of radiotherapy for patients with uterine cervical/endometrial cancer. The Dmax and V10 of FBM1 and the Dmean of FBM2 were significantly associated with the occurrence of grade ≥ 2 HT. The recommended optimal dose constraints were FBM1 Dmax < 53 Gy, V10 < 95%, and FBM2 Dmean <33 Gy.