A modified diffusion-weighted MRI-based model from the radiologist’s perspective: improved performance in determining the surgical resectability for advanced high-grade serous ovarian cancer

Background Complete resection of all visible lesions during primary debulking surgery is associated with the most favorable prognosis in patients with advanced high-grade serous ovarian cancer. An accurate preoperative assessment of resectability is pivotal for tailored management. Objective To assess the potential value of a modified model that integrates the original eight radiological criteria of the Memorial Sloan Kettering Cancer Center model with imaging features of the subcapsular/diaphragm and mesenteric lesions depicted on diffusion-weighted MRI, and growth patterns of all lesions, for predicting the resectability of advanced high-grade serous ovarian cancer. Study design This study included 184 patients with high-grade serous ovarian cancer who underwent preoperative diffusion-weighted MRI between December 2018 and May 2023 at two medical centers. The patient cohort was divided into three subsets: a study cohort (n=100), internal validation cohort (n=46), and external validation cohort (n=38). Preoperative radiological evaluations were independently conducted by two radiologists using both the Memorial Sloan Kettering Cancer Center model and the modified diffusion-weighted MRI-based model. The morphological characteristics of the ovarian tumors depicted on MRI were assessed as either mass-like or infiltrative, and transcriptomic analysis of the primary tumor samples was performed. Univariate and multivariate statistical analyses were performed. Results In the study cohort, both the scores derived using the Memorial Sloan Kettering Cancer Center (intraclass correlation coefficients of 0.980 and 0.959, respectively, both p < 0.001) and modified diffusion-weighted MRI-based models (intraclass correlation coefficients of 0.962 and 0.940, respectively, both p < 0.001) demonstrated excellent intra- and inter-observer agreement. The Memorial Sloan Kettering Cancer Center model (odds ratio = 1.825; 95% CI, 1.390–2.395; p < 0.001) and the modified diffusion-weighted MRI-based model (odds ratio = 1.776; 95% CI, 1.410–2.238; p < 0.001) independently predicted surgical resectability. The modified diffusion-weighted MRI-based model demonstrated improved predictive performance, with an area under the curve of 0.867 in the study cohort, and 0.806 and 0.913 in the internal and external validation cohorts, respectively. Using the modified diffusion-weighted MRI-based model, patients with scores of 0–2, 3–4, 5–6, 7–10, and ≥ 11 achieved complete tumor debulking rates of 90.3%, 66.7%, 53.3%, 11.8%, and 0%, respectively. Most patients with incomplete tumor debulking had infiltrative tumors, and both the Memorial Sloan Kettering Cancer Center and the modified diffusion-weighted MRI-based models yielded higher scores. The molecular differences between the two morphological subtypes were identified. Conclusion Compared to the Memorial Sloan Kettering Cancer Center model, the modified diffusion-weighted MRI-based model demonstrated enhanced accuracy in the preoperative prediction of resectability for advanced high-grade serous ovarian cancer. Patients with scores of 0–6 were eligible for primary debulking surgery.