The aim of the study was to model acute hematologic toxicity (HT) and dose to pelvic osseous structures in anal cancer patients treated with definitive chemo-radiation (CT-RT). A total of 53 patients receiving CT-RT were analyzed. Pelvic bone marrow and corresponding subsites were contoured: ilium, lower pelvis and lumbosacral spine (LSBM). Dose-volume histograms points and mean doses were collected. Logistic regression was performed to correlate dosimetric parameters and ≥G3 HT as endpoint. Normal tissue complication probability (NTCP) was evaluated with the Lyman-Kutcher-Burman (LKB) model. Logistic regression showed a significant correlation between LSBM-mean dose and ≥G3 leukopenia (β coefficient 0.122; p = 0.030; 95% CI 0.012-0.233). According to NTCP modeling, the predicted HT probability had the following parameters: TD50: 37.5 Gy, γ 50: 1.15, m: 0.347. For node positive patients, TD50: 35.2 Gy, γ 50: 2.27, m: 0.176 were found. Node positive patients had significantly higher PBM-V15 (Mean 81.1 vs. 86.7%; p = 0.04), -V20 (Mean 72.7 vs. 79.9%; p = 0.01) and V30 (Mean 50.2 vs. 57.3%; p = 0.03). Patients with a mean LSBM dose >32 Gy had a 1.81 (95% CI 0.81-4.0) relative risk to develop ≥G3 leukopenia. For node positive patients, those risks were 2.67 (95% CI 0.71-10). LKB modeling seems to suggest that LSBM-mean dose should be kept below 32 Gy to minimize ≥G3 HT in anal cancer patients treated with IMRT and concurrent chemotherapy. The contribution of LSBM dose in the development of HT above 25 Gy seems steeper in node positive patients.

Lumbar-sacral bone marrow dose modeling for acute hematological toxicity in anal cancer patients treated with concurrent chemo-radiation

FRANCO, Pierfrancesco
First
;
RAGONA, Riccardo;ARCADIPANE, FRANCESCA;MISTRANGELO, Massimiliano;CASSONI, Paola;MORINO, Mario;RICARDI, Umberto
Last
2016-01-01

Abstract

The aim of the study was to model acute hematologic toxicity (HT) and dose to pelvic osseous structures in anal cancer patients treated with definitive chemo-radiation (CT-RT). A total of 53 patients receiving CT-RT were analyzed. Pelvic bone marrow and corresponding subsites were contoured: ilium, lower pelvis and lumbosacral spine (LSBM). Dose-volume histograms points and mean doses were collected. Logistic regression was performed to correlate dosimetric parameters and ≥G3 HT as endpoint. Normal tissue complication probability (NTCP) was evaluated with the Lyman-Kutcher-Burman (LKB) model. Logistic regression showed a significant correlation between LSBM-mean dose and ≥G3 leukopenia (β coefficient 0.122; p = 0.030; 95% CI 0.012-0.233). According to NTCP modeling, the predicted HT probability had the following parameters: TD50: 37.5 Gy, γ 50: 1.15, m: 0.347. For node positive patients, TD50: 35.2 Gy, γ 50: 2.27, m: 0.176 were found. Node positive patients had significantly higher PBM-V15 (Mean 81.1 vs. 86.7%; p = 0.04), -V20 (Mean 72.7 vs. 79.9%; p = 0.01) and V30 (Mean 50.2 vs. 57.3%; p = 0.03). Patients with a mean LSBM dose >32 Gy had a 1.81 (95% CI 0.81-4.0) relative risk to develop ≥G3 leukopenia. For node positive patients, those risks were 2.67 (95% CI 0.71-10). LKB modeling seems to suggest that LSBM-mean dose should be kept below 32 Gy to minimize ≥G3 HT in anal cancer patients treated with IMRT and concurrent chemotherapy. The contribution of LSBM dose in the development of HT above 25 Gy seems steeper in node positive patients.
2016
33
12:137
1
8
Acute hematologic toxicity; Anal cancer; Concomitant radiochemotherapy; IMRT; VMAT; Volumetric modulated arc therapy
Franco, Pierfrancesco; Ragona, Riccardo; Arcadipane, Francesca; Mistrangelo, Massimiliano; Cassoni, Paola; Rondi, Nadia; Morino, Mario; Racca, Patrizi...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/1611236
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