TY - JOUR
T1 - Differences in delineation guidelines for head and neck cancer result in inconsistent reported dose and corresponding NTCP
AU - Brouwer, Charlotte L.
AU - Steenbakkers, Roel J.H.M.
AU - Gort, Elske
AU - Kamphuis, Marije E.
AU - Van Der Laan, Hans Paul
AU - Van'T Veld, Aart A.
AU - Sijtsema, Nanna M.
AU - Langendijk, Johannes A.
PY - 2014/4
Y1 - 2014/4
N2 - Purpose To test the hypothesis that delineation of swallowing organs at risk (SWOARs) based on different guidelines results in differences in dose-volume parameters and subsequent normal tissue complication probability (NTCP) values for dysphagia-related endpoints. Materials and methods Nine different SWOARs were delineated according to five different delineation guidelines in 29 patients. Reference delineation was performed according to the guidelines and NTCP-models of Christianen et al. Concordance Index (CI), dosimetric consequences, as well as differences in the subsequent NTCPs were calculated. Results The median CI of the different delineation guidelines with the reference guidelines was 0.54 for the pharyngeal constrictor muscles, 0.56 for the laryngeal structures and 0.07 for the cricopharyngeal muscle and esophageal inlet muscle. The average difference in mean dose to the SWOARs between the guidelines with the largest difference (maxΔD) was 3.5 ± 3.2 Gy. A mean ΔNTCP of 2.3 ± 2.7% was found. For two patients, ΔNTCP exceeded 10%. Conclusions The majority of the patients showed little differences in NTCPs between the different delineation guidelines. However, large NTCP differences >10% were found in 7% of the patients. For correct use of NTCP models in individual patients, uniform delineation guidelines are of great importance.
AB - Purpose To test the hypothesis that delineation of swallowing organs at risk (SWOARs) based on different guidelines results in differences in dose-volume parameters and subsequent normal tissue complication probability (NTCP) values for dysphagia-related endpoints. Materials and methods Nine different SWOARs were delineated according to five different delineation guidelines in 29 patients. Reference delineation was performed according to the guidelines and NTCP-models of Christianen et al. Concordance Index (CI), dosimetric consequences, as well as differences in the subsequent NTCPs were calculated. Results The median CI of the different delineation guidelines with the reference guidelines was 0.54 for the pharyngeal constrictor muscles, 0.56 for the laryngeal structures and 0.07 for the cricopharyngeal muscle and esophageal inlet muscle. The average difference in mean dose to the SWOARs between the guidelines with the largest difference (maxΔD) was 3.5 ± 3.2 Gy. A mean ΔNTCP of 2.3 ± 2.7% was found. For two patients, ΔNTCP exceeded 10%. Conclusions The majority of the patients showed little differences in NTCPs between the different delineation guidelines. However, large NTCP differences >10% were found in 7% of the patients. For correct use of NTCP models in individual patients, uniform delineation guidelines are of great importance.
KW - Delineation guidelines
KW - Head and neck
KW - Interobserver variability
KW - NTCP
UR - http://www.scopus.com/inward/record.url?scp=84902123198&partnerID=8YFLogxK
U2 - 10.1016/j.radonc.2014.01.019
DO - 10.1016/j.radonc.2014.01.019
M3 - Article
C2 - 24560759
AN - SCOPUS:84902123198
VL - 111
SP - 148
EP - 152
JO - Radiotherapy and oncology
JF - Radiotherapy and oncology
SN - 0167-8140
IS - 1
ER -