Influence of tumor stage, symptoms, and time of blood draw on serum concentrations of organochlorine compounds in exocrine pancreatic cancer

Knowledge is scant on the relationships between pathophysiologic processes common during cancer progression and changes in blood concentrations of organochlorine compounds (OCs). To analyze the influence of tumor stage, cancer symptoms, and time of blood extraction on serum concentrations of OCs in exocrine pancreatic cancer (EPC). Subjects were 144 incident cases of EPC prospectively recruited in eastern Spain. Blood was drawn and face-to-face interviews with patients were conducted during hospital admission. Information on signs and symptoms was obtained from medical records and patient interviews. OCs were analyzed by high-resolution gas chromatography with electron-capture detection. General linear models were applied to analyze log-transformed OCs corrected for total lipids. Lower concentrations of six of the seven OCs analyzed (p,p'-DDE, three polychlorinated biphenyls, hexachlorobenzene, and beta-hexachlorocyclohexane) were observed in patients with cholestatic syndrome (jaundice, hypocholia, and choluria). The constitutional syndrome increased only p,p'-DDT. The lowering effect of the cholestatic syndrome was stronger than the increasing effect of the constitutional syndrome (fatigue, anorexia, and weight loss), except for p,p'-DDT. When symptoms were considered, stage had only weakly inverse relationships with OC levels. The effects of symptoms on p,p'-DDE, p,p'-DDT, and the three PCBs remained significant after adjusting by the interval from blood extraction to first symptom of EPC, and even when further adjusting by stage. Restriction or adjustment by stage and timing of blood draw may be insufficient to prevent biases associated with cancer progression. Symptoms may enable investigators to assess disease-induced changes in lipophilic exposure biomarkers.