Preoperative risk stratification using ¹⁸F-FDG PET/CT in women with endometrial cancer

Summary

The aim of this study is to evaluate the usefulness of ¹⁸F-FDG PET/CT for preoperative stratification of high-risk and low-risk carcinomas in patients with endometrial cancer. Patients, methods: 60 women (mean age 53.8 ± 9.9 years) with endometrial cancer, who underwent ¹⁸F-FDG PET/CT for preoperative staging work-up, followed by primary cytoreductive surgery, were enrolled in this study. Maximum and mean standardized uptake values (SUVmax, SUVmean) of endometrial tumors were measured, and compared with the various clinicopathologic findings obtained after surgery. Tumour aggressiveness was classified as high-risk and low-risk carcinomas. Patients with stage I or II, endometrioid adenocarcinoma, histologic grade 1 or 2, invasion of less than half of the myometrium, maximum tumor size less than 2.0 cm, and absence of cervical invasion and lymphovascular space involvement (LVSI) were classified as the lowrisk carcinoma group. The remaining patients were classified as the high-risk carcinoma group. Results: In univariate analysis, SUVmax of the primary endometrial tumor was significantly higher in patients who were in a postmenopausal state (p = 0.047), large (> 2 cm) primary tumor (p <0.001), nonendometrioid subtype (p = 0.024), invasion of more than half of the myometrium (p = 0.020), or LVSI (p = 0.004). SUVmax differed significantly according to FIGO stage (p = 0.013) and histologic grade (p <0.001). In multivariate analysis, FIGO stage, histologic grade, LVSI, and maximum tumor size demonstrated a significant association with SUVmax (p <0.001; r = 0.843, r² = 0.711). SUVmean showed similar results. Forty-one (68.3%) patients were diagnosed postoperatively as high-risk and 19 patients (31.7%) as low-risk carcinoma. Patients with high-risk carcinoma (12.1 ± 6.1) showed significantly higher SUVmax than patients with low-risk carcinoma (5.8 ± 2.8, p <0.001). The optimal SUVmax cut-off value of 8.7, determined by ROC analysis, revealed 75.6% sensitivity, 89.5% specificity, and 81.7% accuracy for risk stratification. Conclusion: High-risk endometrial cancer might be differentiated by means of higher SUVmax from low-risk endometrial cancer. ¹⁸F-FDG FDG PET/CT can be applied preoperatively for stratification of risk in patients with endometrial cancer.

Zusammenfassung

Das Ziel dieser Studie ist die Nutzenbewertung der ¹⁸F-FDG PET/CT für die präoperative Stratifizierung von Hochrisiko- und Niedrigrisiko- Karzinomen bei Patientinnen mit Endometriumkarzinom. Patienten, Methoden: Es wurden 60 Frauen (mittleres Alter 53,8 ± 9,9 Jahre) mit Endometriumkarzinom in diese Studie aufgenommen, die im Rahmen des präoperativen Stagings einer ¹⁸F-FDG-PET/CT und einer anschließenden primären zytoreduktiven Operation unterzogen wurden. Die maximalen und mittleren standardisierten Aufnahmewerte (SUVmax, SUVmean) des endometrialen Tumors wurden gemessen und mit den verschiedenen, postoperativ erhobenen klinisch-pathologischen Befunden verglichen. Die Aggressivität des Tumors wurde als Hochrisikound Niedrigrisiko-Karzinom klassifiziert. In die Gruppe der Niedrigrisiko-Karzinome wurden Patientinnen eingeordnet, die ein Stadium I oder II, endometrioides Adenokarzinom, einen histologischen Grad 1 oder 2, eine Invasion von weniger als der Hälfte des Myometriums, maximale Tumorgröße von weniger als 2,0 cm und keinen Befall der Zervix oder Lymphgefäßeinbruch (LVSI) aufwiesen. Die verbleibenden Patientinnen wurden als Gruppe der Hochrisikokarzinome klassifiziert. Ergebnisse: In der univariaten Analyse war SUVmax des primären Endometriumtumors signifikant höher bei postmenopausalen Patientinnen (p = 0,047), großen (> 2 cm) Primärtumoren (p <0,001), nicht endometrioidem Subtyp (p = 0,024), Invasion von mehr als der Hälfte des Myometriums (p = 0,020) oder LVSI (p = 0,004). SUVmax zeigte signifikante Unterschiede je nach FIGO-Stadium (p = 0,013) und histologischem Grad (p <0,001). In der multivariaten Analyse zeigten das FIGO-Stadium, der histologische Grad, LVSI und die maximale Tumorgröße einen signifikanten Zusammenhang mit SUVmax (p <0,001; r = 0,843, r² = 0,711). SUVmean ergab ähnliche Resultate. Bei 41 Patientinnen (68,3%) wurde der Tumor postoperativ als Hochrisikokarzinom und bei 19 Patientinnen (31,7%) als Niedrigrisikokarzinom diagnostiziert. Patientinnen mit Hochrisikokarzinom (12,1 ± 6,1) wiesen signifikant höhere SUVmax-Werte auf als Patientinnen mit Niedrigrisikokarzinom (5,8 ± 2,8, p < 0,001). Der optimale, durch ROC-Analyse bestimmte Cut-off-Wert von 8,7 für SUVmax zeigte 75,6% Sensitivität, 89,5% Spezifität und 81,7% Treffsicherheit bei der Risikostratifizierung. Schlussfolgerung: Das Hochrisiko-Endometriumkarzionom kann mittels hÖherer SUVmax-Werte vom Niedrigrisiko-Endometriumkarzinom abgegrenzt werden. Die 18F-FDG FDG PET/CT kann präoperativ für die Stratifizierung von Risikopatientinnen mit Endometriumkarzinom eingesetzt werden.

Keywords

FDG PET/CT - SUV - preoperative risk stratification - endometrial cancer

Schlüsselwörter

FDG PET/CT - SUV - präoperative Risikostratifizierung - Endometriumkarzinom

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