Accuracy of 18F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography for Detection of Recurrent or Metastatic Colorectal Carcinoma in Patients with Rising Carcinoembryonic Antigen Levels

Full Article

WL Yu, SM Wong, K Wang, AT Ahuja

Hong Kong J Radiol 2014;17:9-15

DOI: 10.12809/hkjr1413186

Objective: A rise in carcinoembryonic antigen level is commonly encountered during follow-up of patients with colorectal carcinoma. This study aimed to evaluate the diagnostic performance of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) studies for detection of recurrent or metastatic colorectal carcinoma in patients with rising carcinoembryonic antigen levels.

Methods: Patients with colorectal carcinoma in clinical remission with rising carcinoembryonic antigen levels who underwent PET/CT in Prince of Wales Hospital, Hong Kong from 2008 to 2011 were included. Patient demographics, carcinoembryonic antigen levels, and clinical follow-up data were recorded. Outcomes were determined by histopathological findings or at least 12-month follow-up.

Results: Forty-two PET/CT studies of 37 patients (16 men and 21 women; mean [standard deviation] age, 65.8 [11.6] years) were included. Carcinoembryonic antigen levels ranged from 1.8 to 45 µg/l (9 patients had normal carcinoembryonic antigen levels of <5 µg/l, but serial carcinoembryonic antigen measurements showed a rising trend). Among the 42 events, 23 (55%) had a positive final diagnosis. The sensitivity, specificity, and positive and negative predictive values of PET/CT for recurrence or metastases were 91.3%, 89.5%, 91.3%, and 89.5%.

Conclusion: 18F-FDG PET/CT is a useful imaging modality to evaluate recurrence or metastases in patients with colorectal carcinoma in clinical remission but showing rising carcinoembryonic antigen levels.




余黃莉、王先民、王琪、AT Ahuja


目的:癌胚抗原(CEA)水平上升常出現於結直腸癌患者隨訪期間。本研究針對CEA水平上升的結直腸癌患者,評估使用18F-脫氧葡萄糖正電子發射斷層掃描/電腦斷層掃描(18F-FDG PET / CT)診斷腫瘤復發或轉移的表現。

方法:2008至2011年期間於香港威爾斯親王醫院接受18F-FDG PET / CT掃描,臨床症狀緩解而CEA水平上升的結直腸癌患者被列入研究範圍。本研究記錄病人的人口學資料、CEA水平和臨床隨訪資料。由組織病理學發現或至少12個月的隨訪來決定結果。

結果:37名患者的42次PET / CT掃描納入研究,包括16名男性和21名女性,平均年齡65.8歲(標準差11.6歲)。患者的CEA水平介乎1.8至45 µg/l(其中9例為5 µg/l以下,屬正常水平,但連續檢測呈上升趨勢)。42例中,23例(55%)最終診斷為陽性。PET / CT對復發或轉移結直腸癌的敏感性、特異性、陽性和陰性預測值分別為91.3%、89.5%、91.3%和89.5%。

結論:對於臨床緩解但CEA水平上升的結直腸癌患者,18F-FDG PET / CT是評估腫瘤復發或轉移的有效成像工具。