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.

中文摘要

使用18F-脫氧葡萄糖正電子發射斷層掃描／電腦斷層掃描為癌胚抗原水平上升的結直腸癌患者檢測腫瘤復發或轉移的準確度

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。