Diagnostic utility of interleukin-6 (IL-6) for primary bile duct cancer and changes in serum IL-6 levels following photodynamic therapy.
OBJECTIVE
Difficult diagnoses and a lack of effective therapy complicate biliary tract malignancies. Interleukin-6 (IL-6) is a human bile duct epithelium growth factor correlated with tumor burden. We evaluated the usefulness of serum IL-6 in the diagnosis of primary BDC and measured changes in serum IL-6 levels following photodynamic therapy (PDT).


METHODS
We prospectively measured serum IL-6 levels in patients with BDC (N = 26: 14 patients treated with PDT, 12 with biliary drainage alone), hepatocelluar carcinoma (HCC, N = 26), and healthy adults (N = 23). Serum IL-6 levels were measured by an enzyme-linked immunosorbent assay. Patients with clinical conditions known to increase IL-6 levels were excluded.


RESULTS
IL-6 was detected in all patients with BDC and HCC, and in 6 of 23 healthy adults. Median and mean levels of IL-6 were higher in patients with BDC than in both other groups (P < 0.001). Using a 25.8 pg/mL cutoff, IL-6 provided a diagnostic sensitivity of 73% and a specificity of 92%; positive and negative predictive values were 83% and 87%, respectively. Serum levels of IL-6 were correlated with tumor burden in BDC patients. One month after treatment of BDC with PDT, the mean IL-6 level decreased significantly from 282.1 +/- 121.8 to 38.2 +/- 9.9 pg/mL (P= 0.008).


CONCLUSIONS
Serum IL-6 concentration is a useful addition to the available tests for the differential diagnosis of BDC, and serves as a marker for monitoring the response to treatment of BDC with PDT.
Cheon
Young Koog
YK
Institute for Digestive Research and Digestive Disease Center, Soon Chun Hyang University College of Medicine, Seoul, Korea.
Cho
Young Deok
YD
Moon
Jong Ho
JH
Jang
Jae Young
JY
Kim
Young Seok
YS
Kim
Yun Soo
YS
Lee
Moon Sung
MS
Lee
Joon Seong
JS
Shim
Chan Sup
CS
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001650:Bile Duct Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000628:therapy; D001653:Bile Ducts, Intrahepatic; D015415:Biomarkers / Q000097:blood; D018281:Cholangiocarcinoma / Q000097:blood* / Q000175:diagnosis* / Q000628:therapy; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D011237:Predictive Value of Tests; D047368:Tumor Burden / Q000502:physiology
D015415:Biomarkers; D015850:Interleukin-6