Tesis

Performa Circulating Tumour Cells dan Carcinoembryonic Antigen dalam Mendiagnosis Kanker Kolorektal Metastatik = Internal Medicine Subspeciality : Gastroenterology-Hepatology Title : Performance of Circulating Tumour Cells and Carcinoembryonic Antigen in Diagnosing Metastatic Colorectal Cancer.

Latar Belakang : Kanker kolorektal (KKR) merupakan kanker yang ditemukan pada kolon dan rektum dan sering telah mengalami metastasis saat diagnosis ditegakkan. Pemeriksaan baku emas untuk menegakkan diagnosis KKR metastatik adalah dengan histopatologi yang didapatkan dari biopsi saat kolonoskopi dan pemeriksaan pencitraan seperti CT scan atau PET CT. Kolonoskopi dan pemeriksaan pencitraan bersifat invasif dan memiliki risiko sehingga dikembangkan metode biopsi cair untuk mendeteksi circulating tumour cells (CTC) pada darah perifer. Pemeriksaan carcinoembryonic antigen (CEA) juga makin berkembang dan digunakan dalam diagnosis KKR metastatik. Pemeriksaan CTC, CEA dan kombinasi kedua pemeriksaan ini diharapkan dapat digunakan sebagai penanda diagnosis non-invasif dalam mendiagnosis KKR metastatik. Tujuan : Penelitian ini bertujuan untuk mengetahui performa CTC, CEA, dan kombinasi keduanya dalam mendiagnosis KKR metastatik. Metode : Penelitian ini merupakan studi potong lintang pada pasien KKR di RSCM, RS Kanker Dharmais dan RS Fatmawati Jakarta selama bulan Desember 2024 hingga April 2025. Analisis uji diagnostik digunakan untuk mencari titik potong, area under curve (AUC) serta nilai sensitivitas, spesifisitas, nilai duga positif (NDP), nilai duga negatif (NDN), rasio kemungkinan positif (RKP) dan rasio kemungkinan negatif (RKN) dalam mendiagnosis KKR metastatik. Hasil : Sebanyak total 160 subjek penelitian, didapatkan KKR metastatik sebanyak 72 orang (45%) dan KKR nonmetastatik 88 orang (55%). Performa CTC dengan metode gradien densitas dalam mendiagnosis KKR metastatik buruk. Pada titik potong CTC ≥ 34,5 sel/3 ml didapatkan AUC 0,579 dengan sensitivitas 56,94% dan spesifisitas 50%. Performa CEA dalam mendiagnosis KKR metastatik baik. Pada titik potong CEA ≥ 18,31 ng/ml didapatkan AUC 0,811 dengan sensitivitas 72,22% dan spesifisitas 72,73%. Performa kombinasi CTC dan CEA dalam mendiagnosis KKR metastatik sedang, dengan AUC 0,703, sensitivitas 91,67% dan spesifisitas 37,5%. Simpulan : Performa CTC metode gradien densitas dalam mendiagnosis KKR metastatik adalah buruk, performa CEA baik dan performa kombinasi CTC dan CEA sedang.
Kata kunci : Kanker kolorektal , circulating tumour cells, carcinoembryonic antigen, gradien densitas.


Background : Colorectal cancer (CRC) is a type of cancer found in the colon and rectum, and it is often already metastatic at the time of diagnosis. The gold standard for diagnosing metastatic CRC is histopathological examination obtained from a biopsy during colonoscopy, along with imaging tests such as a CT scan or PET-CT. Colonoscopy and imaging are invasive and carry certain risks, which has led to the development of liquid biopsy methods to detect circulating tumour cells (CTCs) in peripheral blood. The carcinoembryonic antigen (CEA) test has also been increasingly developed and used in diagnosing metastatic CRC. CTC testing, CEA testing, and a combination of are expected to serve as non-invasive diagnostic markers for identifying metastatic colorectal cancer. Objective : This study aims to evaluate the performance of CTC, CEA, and their combination in diagnosing metastatic colorectal cancer. Method : This study is a cross-sectional study conducted on CRC patients at Cipto Mangunkusumo Hospital (RSCM), Dharmais Cancer Hospital, and Fatmawati Hospital from December 2024 to April 2025. Diagnostic test analysis was used to determine cutoff points, the area under the curve (AUC) as well as the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) in diagnosing metastatic colorectal cancer. Result : A total of 160 study subjects were included, consisting of 72 (45%) with metastatic CRC and 88 (55%) with non-metastatic CRC. The performance of CTC with density gradient method in diagnosing metastatic CRC was poor. Using a cutoff point of ≥34.5 cells/3 ml, CTC showed AUC of 0.579, a sensitivity of 56.94% and a specificity of 50%. The performance of CEA in diagnosing metastatic CRC was good. At a cutoff point of ≥18.31 ng/ml, CEA demonstrated AUC of 0.811, a sensitivity of 72.22% and specificity of 72.73%. The performance of the combined CTC and CEA in diagnosing metastatic CRC was moderate, with an AUC of 0.703, sensitivity of 91.67%, and specificity of 37.5%. Conclusion : The performance of CTC with density gradient method in diagnosing metastatic colorectal cancer is poor, CEA is good, and the combination of CTC and CEA is moderate.
Key words : Colorectal cancer, circulating tumour cells, carcinoembryonic antigen, density gradient.