EP288 Prospective intra/inter-observer evaluation of pre-brachytherapy cervical cancer tumor width measured in TRUS and MR imaging

• Published in: International journal of gynecological cancer Vol. 29; no. Suppl 4; p. A212
• Main Authors: Federico, M, Hernandez Socorro, CR, Ribeiro, I, Rey Baltar Oramas, MD, Zaiac, M, Lloret, M
• Format: Journal Article
• Language: English
• Published: Oxford BMJ Publishing Group LTD 01.11.2019
• Subjects: Cervical cancer; Radiation therapy
• ISSN: 1048-891X; 1525-1438
• DOI: 10.1136/ijgc-2019-ESGO.349

Introduction/BackgroundUS imaging due to its limited cost is under intense investigation as base for dose adaptation in cervical cancer brachytherapy. This work test inter/intra-observer uncertainties between MR and TRUS imaging defining maximum tumor width before first BT application in a prospective cohort of cervical cancer patients undergoing IGABT.Methodology110 consecutive cervical cancer patients were included. Before first BT implant underwent MR and TRUS scan with no applicator in place. Images were independently analyzed by three examiners, blinded to the other’s results. With clinical information at hand, maximum tumor width was measured on preBT TRUS and MR (figure.1). Quantitative agreement analysis was undertaken. Intra-class correlation coefficient (ICC), Passing-Bablok and Bland Altman plots were used to evaluate the intra/inter-observers agreement.ResultsAverage difference between HRCTVMR and HRCTVTRUS was 1.3±3.2 mm (p<0.001); 1.1±4.6 mm (p=0.01) and 0.7±3 mm (p=0.01). Error was less than 3 mm in 79%, 82% and 80% of the measurements for the three observers, respectively. Intra-observer ICC was 0.96 (CI 95% 0.94–0.97), 0.93 (CI 95% 0.9–0.95) and 0.96 (CI 95% 0.95–0.98) respectively. Inter-observer ICC for HRCTVMR width measures was 0.92 (CI 95% 0.89–0.94) with no difference among FIGO stages. Inter-observer ICC for HRCTVTRUS was 0.86 (CI 95% 0.81–0.9). For FIGO stage I/II, ICC HRCTVTRUS values were comparable to respective HRCTVMR values. For larger tumors HRCTVTRUS inter-observer ICC values were lower than respective HRCTVMR although remaining acceptable (table 1).ConclusionTRUS is equivalent to MR in assessing preBT tumor maximum width in cervical cancer FIGO stage I/II. In advanced stages TRUS is slightly inferior to MR.DisclosureNothing to disclose.Abstract EP288 Table 1Inter-observer agreement analysis of tumor maximum width measurements Tumor width MR Tumor width TRUS ICC (intrcalss correlation coefficient) CI 95 % ICC (intrcalss correlation coefficient) CI 95 % All stages 0.92 [0.89–0.94] 0.86 [0.81–0.9] FIGO I 0.87 [0.75–0.94] 0.88 [0.76–0.95] FIGO II 0.81 [0.74–0.87] 0.79 [0.7–0.86] FIGO III 0.88 [0.75–0.96] 0.69 [0.42–0.87] FIGO IV 0.93 [0.83–0.98] 0.62 [0.26–0.87] Abstract EP288 Figure 1