Unenhanced MRI of the abdomen and pelvis for surveillance of patients with stage 1 testicular cancer post-radical orchiectomy.

To evaluate the ability of unenhanced magnetic resonance imaging (MRI) to detect metastatic lymphadenopathy in men with stage 1 testicular cancer on surveillance.

With IRB approval, we identified 23 consecutive men with stage 1 testicular cancer (diagnosed after orchiectomy) undergoing surveillance with unenhanced MRI of the abdomen and pelvis. Three blinded radiologists (2 inexperienced R1/R2 and 1 experienced R3) independently assessed MRI for: presence, location and size of abnormal lymph nodes and degree of confidence (5-point Likert scale) in diagnosis. Diagnostic accuracy was tabulated and compared between groups using ROC. Inter-observer agreement was assessed using Cohen's kappa statistic.

17.4% (4/23) men developed 6 metastatic lymph nodes (reference standard: interval development from baseline, size > 1.0 cm short axis). R1 and R2 detected 75% (3/4) patients with abnormal lymph nodes, compared to R3 who detected all four cases. False positive interpretations occurred in: 5.2% (1/19) R1, 10.5% (2/19) R2 and no patients for R3. Sensitivity, specificity and area under the ROC curve (AUC) were: R1: 75% (95% CI 19.4-99.4%), 94.7% (74.0-99.9%) and 0.85 (0.59-1.00), R2: 75% (19.4-99.4%), 89.5% (66.9-98.7%) and 0.82 (0.57-1.00) and, R3: 100% (95% 39.8-100.0%), 100% (82.4-100%) and 1.00 (1.00-1.00) with no difference in AUC between readers (p = 0.383). Comparison in accuracy between readers is limited due to the small sample size. Inter-observer agreement was substantial (K = 0.62). Median (range) degree of confidence scores were rated: R1 5 (5-5), R2 4 (3-5) and, R3 5 (5-5).

In this study, unenhanced MRI was adequate for surveillance of stage 1 testicular cancer; however, radiologist inexperience may lead to errors.

Abdominal radiology (New York). 2020 Sep 08 [Epub ahead of print]

Rishi Narine, Heba Osman, Sirote Wongwaisayawan, Scott Morgan, Luke T Lavallee, Nicola Schieda

Department of Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada., Division of Radiation Oncology, Department of Medical Imaging, The Ottawa Hospital, Ottawa, ON, Canada., Division of Urology, Department of Surgery, The Ottawa Hospital, Ottawa, ON, Canada., Department of Medical Imaging, The Ottawa Hospital, 1053 Carling Avenue, Room C159, Ottawa, ON, K1Y 4E9, Canada. .

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