Interobserver agreement and prognostic impact for MRI-based 2018 FIGO staging parameters in uterine cervical cancer

Abstract

Objectives: To evaluate the interobserver agreement for MRI-based 2018 International Federation of Gynecology and Obstetrics (FIGO) staging parameters in patients with cervical cancer and assess the prognostic value of these MRI parameters in relation to other clinicopathological markers.

Methods: This retrospective study included 416 women with histologically confirmed cervical cancer who underwent pretreatment pelvic MRI from May 2002 to December 2017. Three radiologists independently recorded MRI-derived staging parameters incorporated in the 2018 FIGO staging system. Kappa coefficients (κ) for interobserver agreement were calculated. The predictive and prognostic values of the MRI parameters were explored using ROC analyses and Kaplan-Meier with log-rank tests, and analyzed in relation to clinicopathological patient characteristics.

Results: Overall agreement was substantial for the staging parameters: tumor size > 2 cm (κ = 0.80), tumor size > 4 cm (κ = 0.76), tumor size categories (≤ 2 cm; > 2 and ≤ 4 cm; > 4 cm) (κ = 0.78), parametrial invasion (κ = 0.63), vaginal invasion (κ = 0.61), and enlarged lymph nodes (κ = 0.63). Higher MRI-derived tumor size category (≤ 2 cm; > 2 and ≤ 4 cm; > 4 cm) was associated with a stepwise reduction in survival (p ≤ 0.001 for all). Tumor size > 4 cm and parametrial invasion at MRI were associated with aggressive clinicopathological features, and the incorporation of these MRI-based staging parameters improved risk stratification when compared to corresponding clinical assessments alone.

Conclusion: The interobserver agreement for central MRI-derived 2018 FIGO staging parameters was substantial. MRI improved the identification of patients with aggressive clinicopathological features and poor survival, demonstrating the potential impact of MRI enabling better prognostication and treatment tailoring in cervical cancer.

Key points: • The overall interobserver agreement was substantial (κ values 0.61-0.80) for central MRI staging parameters in the 2018 FIGO system. • Higher MRI-derived tumor size category was linked to a stepwise reduction in survival (p ≤ 0.001 for all). • MRI-derived tumor size > 4 cm and parametrial invasion were associated with aggressive clinicopathological features, and the incorporation of these MRI-derived staging parameters improved risk stratification when compared to clinical assessments alone.

Keywords: Magnetic resonance imaging; Observer variation; Prognosis; Risk assessment; Uterine cervical neoplasms.

Conflict of interest statement

The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.

© 2022. The Author(s).

Figures

Fig. 1

Cervical cancer depicted by sagittal (top) and axial oblique (bottom) T2-weighted MRI views in three patients. a A 40-year-old woman with a moderately large cervical cancer (white arrows) with a maximum tumor size of 2.4 cm (dotted line). The tumor is confined to the cervical stroma, and there are no enlarged lymph nodes (2018 FIGO IB2). The patient received primary surgical treatment (radical hysterectomy and salpingectomy) and had no signs of recurrence at 4 years post treatment. b A 23-year-old woman with a large cervical cancer (white arrows) with a maximum tumor size of 6.0 cm (dotted line). The tumor invades the parametrium (short white arrow), and bilateral enlarged pelvic lymph nodes are depicted (black arrows) (2018 FIGO IIIC1). The patient was treated with primary chemoradiation therapy and died from cervical cancer 2.5 years after primary diagnosis. c A 70-year-old woman with a large, irregular cervical cancer (white arrows) that extends to the uterine fundus and the lower third of the vagina. The maximum tumor size is 10.0 cm (dotted line) and tumor invades the parametrium (short white arrows) and both the bladder and rectum (black dotted arrows) (2018 FIGO IVA). The patient received primary chemoradiation therapy and died from cervical cancer 8 months after primary diagnosis. FIGO, International Federation of Gynecology and Obstetrics

Fig. 2

Kaplan–Meier survival curves depicting significantly reduced disease-specific survival in patients with (a) 2009 FIGO stages IB2–IIA and ≥ IIB compared to stages ≤ IB1, (b) higher MRI–derived tumor size categories, (c) clinical tumor size ≤ 4 cm but MRI–derived tumor size > 4 cm, (d) 2009 FIGO stages I–IIA but parametrial invasion at MRI. For each category: total number of cases/number of cases with disease-specific death. FIGO, International Federation of Gynecology and Obstetrics

Fig. 3

Time-dependent receiver operating characteristic (ROC) curves for prediction of disease-specific death at 5 years after primary diagnosis for MRI–derived tumor size > 2 cm (a), tumor size > 4 cm (b), parametrial invasion (c), vaginal invasion (d), enlarged lymph nodes (defined as pelvic/paraaortic lymph nodes with short-axis diameter > 1 cm) (e), and bladder/rectum invasion (f), for the three readers and the consensus reading. p values refer to the test of equal AUC values across readers and consensus reading. For the pairwise comparisons, only significant p values are given (after Holm–Bonferroni correction: p < 0.008)

Fig. 4

Time-dependent ROC curves for prediction of disease-specific death at 5 years after primary diagnosis for MRI–derived tumor size > 2 cm, tumor size > 4 cm, parametrial invasion, vaginal invasion, enlarged lymph nodes (defined as pelvic/paraaortic lymph nodes with short-axis diameter > 1 cm), and bladder/rectum invasion (consensus reading for all variables). p values refer to the test of equal AUC values across the MRI–derived staging parameters. For the pairwise comparisons, only significant p values are given (after Holm–Bonferroni correction: p < 0.005)