Annals of Oncology

abstracts
86P
Serum interleukin-6 as a prognostic biomarker for survival in
patients with unresectable pancreatic cancer
I. Chen 1 , C. Dehlendorff 2 , B.V. Jensen 1 , P. Pfeiffer 3 , S.E. Nielsen 1 , N.H. Holländer 4 ,
M.K. Yilmaz 5 , J. Johansen 1
1 Oncology, Herlev and Gentofte Hospital, Herlev, Denmark, 2 Research Center,
Danish Cancer Society Institute of Cancer Biology, Copenhagen, Denmark,
3 Department of Oncology, Odense University Hospital, Odense, Denmark,
4 Oncology, Zealand University Hospital, Naestved, Denmark, 5 Department of
Oncology, Aalborg University Hospital, Aalborg, Denmark
Background: Patients with pancreatic cancer (PC) have the highest mortality rate of all
major cancers. Interleukin-6 (IL-6) is produced by PC cells and macrophages, regulates
inflammation and plays an important role in cachexia. The aim of this biomarker study
was to determine the clinical utility of serum IL-6 as a prognostic factor. We further
explored age, sex, CA 19.9, PS, stage and chemotherapy type as predictors of outcome
in patients receiving palliative chemotherapy.
Methods: 452 patients with unresectable PC (M/F: 242/210; median age 67.5 (IQR
61.8, 73.0); ECOG Performance Status (PS) of 0/1/2: 150/247/55; locally advanced
disease/metastatic: 97/355; treated with gemcitabine n = 337, FOLFIRINOX n= 83,
gemcitabine and nab-Paclitaxel n = 14 or capecitabine-containing regimens n = 18)
were included in the BIOPAC study from five hospitals in Denmark (2008-2016).
Pretreatment and longitudinal serum CA 19.9 (Siemens) and IL-6 were determined
(ELISA, R&D Systems).
Results: Patients were grouped into quartiles according to baseline IL-6 values (0.8 to
3.2, 3.2 to 6.4, 6.4 to 14, and ≥14 pg/ml) and CA 19.9 values (1 to 119, 119 to 992, 992
to 7280, and 7280 to 687.000 U/ml. On univariate analysis, IL-6 ≥6.4 pg/ml, CA 19.9,
PS, stage, chemotherapy type were identified as significant risk factors for overall
survival (OS). Hazard ratio (HR) in quartiles with lowest quartile as reference were 1.20
(95% confidence interval (CI), 0.91–1.57; P = 0.19), 1.87 (95% CI, 1.43–2.46;
P < 0.001), and 2.81 (95% CI, 2.14–3.70; P < 0.001), for IL-6 groups 2–4, respectively.
Multivariate cox analysis showed that apart from age and sex all variables were
independently associated with short OS. The hazard rate of death for patients with
IL-6 ≥ 14 pg/ml was 2.23 times as high as those with IL-6