Time-dependent dose-response relation for absence of vaginal elasticity after gynecological radiation therapy
2016 (English)In: Radiotherapy and Oncology, ISSN 0167-8140, E-ISSN 1879-0887, Vol. 120, no 3, 537-541 p.Article in journal (Refereed) Published
Background and purpose: To investigate the dose-response relation between the dose to the vagina and the patient-reported symptom absence of vaginal elasticity and how time to follow-up influences this relation. Material and methods: The study included 78 long-term gynecological cancer survivors treated between 1991 and 2003 with external beam radiation therapy. Of those, 24 experienced absence of vaginal elasticity. A normal tissue complication model is introduced that takes into account the influence of time to follow-up on the dose-response relation and the patients age. The best estimates of the dose-response parameters were calculated using Probit, Probit-Relative Seriality (RS) and Probit-time models. Log likelihood (LL) values and the Akaike Information Criterion (AIC) were used to evaluate the model fit. Results: The dose-response parameters for absence of vaginal elasticity according to the Probit and Probit-time models with the 68% Confidence Intervals (CI) were: LL = 39.8, D-50 = 49.7 (47.2-52.4) Gy, gamma(50) =1.40 (1.12-1.70) and LL = 37.4, D-50 = 46.9 (43.5-50.9) Gy, gamma(50) = 1.81 (1.17-2.51) respectively. Conclusions: The proposed model, which describes the influence of time to follow-up on the dose response relation, fits our data best. Our data indicate that the steepness of the dose-response curve of the dose to the vagina and the symptom absence of vaginal elasticity increases with time to follow-up, while D-50 decreases. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
Place, publisher, year, edition, pages
ELSEVIER IRELAND LTD , 2016. Vol. 120, no 3, 537-541 p.
Dose-response relation; NTCP; Gynecological radiation therapy; Vaginal elasticity; Time-response relation
Radiology, Nuclear Medicine and Medical Imaging
IdentifiersURN: urn:nbn:se:liu:diva-132545DOI: 10.1016/j.radonc.2016.02.013ISI: 000385328000027PubMedID: 26907514OAI: oai:DiVA.org:liu-132545DiVA: diva2:1046354
Funding Agencies|Swedish Cancer Society - Sweden [CAN 2006/1321, CAN 2009/1099]; Cancer Research Funds of Radiumhemmet; King Gustav V Jubilee Clinic Cancer Foundation in Gothenburg - Sweden; Swedish State under the ALF agreement in Stockholm - Sweden; Swedish State under the ALF agreement in Gothenburg - Sweden2016-11-142016-11-132016-11-14