TY - JOUR
T1 - External validation of a prognostic CT-based radiomic signature in oropharyngeal squamous cell carcinoma
AU - Leijenaar, Ralph T. H.
AU - Carvalho, Sara
AU - Hoebers, Frank J. P.
AU - Aerts, Hugo J. W. L.
AU - Van Elmpt, Wouter J. C.
AU - Huang, Shao Hui
AU - Chan, Biu
AU - Waldron, John N.
AU - O'Sullivan, Brian
AU - Lambin, Philippe
PY - 2015/10/21
Y1 - 2015/10/21
N2 - Background. Oropharyngeal squamous cell carcinoma (OPSCC) is one of the fastest growing disease sites of head and neck cancers. A recently described radiomic signature, based exclusively on pre-treatment computed tomography (CT) imaging of the primary tumor volume, was found to be prognostic in independent cohorts of lung and head and neck cancer patients treated in the Netherlands. Here, we further validate this signature in a large and independent North American cohort of OPSCC patients, also considering CT artifacts.Methods. A total of 542 OPSCC patients were included for which we determined the prognostic index (PI) of the radiomic signature. We tested the signature model fit in a Cox regression and assessed model discrimination with Harrell's c-index. Kaplan-Meier survival curves between high and low signature predictions were compared with a log-rank test. Validation was performed in the complete cohort (PMH1) and in the subset of patients without (PMH2) and with (PMH3) visible CT artifacts within the delineated tumor region.Results. We identified 267 (49%) patients without and 275 (51%) with visible CT artifacts. The calibration slope () on the PI in a Cox proportional hazards model was 1.27 (H-0: = 1, p = 0.152) in the PMH1 (n = 542), 0.855 (H-0: = 1, p = 0.524) in the PMH2 (n = 267) and 1.99 (H-0: = 1, p = 0.002) in the PMH3 (n = 275) cohort. Harrell's c-index was 0.628 (p = 2.72e-9), 0.634 (p = 2.7e-6) and 0.647 (p = 5.35e-6) for the PMH1, PMH2 and PMH3 cohort, respectively. Kaplan-Meier survival curves were significantly different (p <0.05) between high and low radiomic signature model predictions for all cohorts.Conclusion. Overall, the signature validated well using all CT images as-is, demonstrating a good model fit and preservation of discrimination. Even though CT artifacts were shown to be of influence, the signature had significant prognostic power regardless if patients with CT artifacts were included.
AB - Background. Oropharyngeal squamous cell carcinoma (OPSCC) is one of the fastest growing disease sites of head and neck cancers. A recently described radiomic signature, based exclusively on pre-treatment computed tomography (CT) imaging of the primary tumor volume, was found to be prognostic in independent cohorts of lung and head and neck cancer patients treated in the Netherlands. Here, we further validate this signature in a large and independent North American cohort of OPSCC patients, also considering CT artifacts.Methods. A total of 542 OPSCC patients were included for which we determined the prognostic index (PI) of the radiomic signature. We tested the signature model fit in a Cox regression and assessed model discrimination with Harrell's c-index. Kaplan-Meier survival curves between high and low signature predictions were compared with a log-rank test. Validation was performed in the complete cohort (PMH1) and in the subset of patients without (PMH2) and with (PMH3) visible CT artifacts within the delineated tumor region.Results. We identified 267 (49%) patients without and 275 (51%) with visible CT artifacts. The calibration slope () on the PI in a Cox proportional hazards model was 1.27 (H-0: = 1, p = 0.152) in the PMH1 (n = 542), 0.855 (H-0: = 1, p = 0.524) in the PMH2 (n = 267) and 1.99 (H-0: = 1, p = 0.002) in the PMH3 (n = 275) cohort. Harrell's c-index was 0.628 (p = 2.72e-9), 0.634 (p = 2.7e-6) and 0.647 (p = 5.35e-6) for the PMH1, PMH2 and PMH3 cohort, respectively. Kaplan-Meier survival curves were significantly different (p <0.05) between high and low radiomic signature model predictions for all cohorts.Conclusion. Overall, the signature validated well using all CT images as-is, demonstrating a good model fit and preservation of discrimination. Even though CT artifacts were shown to be of influence, the signature had significant prognostic power regardless if patients with CT artifacts were included.
U2 - 10.3109/0284186X.2015.1061214
DO - 10.3109/0284186X.2015.1061214
M3 - Article
C2 - 26264429
SN - 0284-186X
VL - 54
SP - 1423
EP - 1429
JO - Acta Oncologica
JF - Acta Oncologica
IS - 9
ER -