Bone marrow toxicity in patients with locally advanced cervical cancer undergoing multimodal treatment with VMAT/IMRT: are there dosimetric predictors for toxicity?

For women with locoregionally advanced cervical cancer, the standard of care treatment is the curatively intended chemoradiation therapy (CRT). A relationship between bone marrow (BM) dose-volume histograms (DVHs) and acute hematological toxicity (HT) has been debated recently. Aim of this study was the evaluation of BM dose constraints and HT in a contemporary patient cohort.

Radiation treatment plans of 31 patients with cervical cancer (FIGO stage IIB-IVB) treated with intensity-modulated radiotherapy and simultaneous chemotherapy were explored retrospective. Pelvic bones (PB) and femoral heads (FH) were contoured and DVHs were correlated with white blood cells (WBC), hemoglobin levels and platelets.

Comparing the absolute blood levels with the dose volumes of both FH and PB the data showed a significant correlation between WBC and the median dose of the FH and the median dose, V_30Gy, V_40Gy and V_50Gy of the PB. A correlation between the toxicity grade of anemia and mean dose, maximum dose and V_5Gy of the PB was found. Counting the highest grade of HT of all three blood levels of each patient, significant correlations were found for the mean and median dose, V_30Gy, V_40Gy and V_50Gy of the PB.

The results show that blood levels may correlate with distinct dosimetric subvolumes of critical bone marrow compartments with a potential impact on therapeutic outcome and treatment-related toxicity. The data presented are in line with the previous findings on the relevance of dosimetric exposure of pelvic bony subvolumes.