Anticipatory symptoms and anticipatory immune responses in pediatric cancer patients receiving chemotherapy: Features of a classically conditioned response?

There is considerable evidence from studies in adult patients that classica l conditioning contributes to anticipatory nausea and/or vomiting (ANV) in cancer chemotherapy: The stimuli predicting the infusion serve as condition ed stimuli (CS). When reexposed to the CS, some patients experience ANV pri or to infusion onset. In adult patients, anticipatory immunomodulation (AIM ) has also been observed. The present study examines whether ANV and AIM oc cur in pediatric cancer patients and whether they show features of a condit ioned response. Methods: Nineteen pediatric cancer patients (M = 10.1 years , > 2 previous chemotherapies) were studied over two consecutive cycles (A, B). In both cycles, self-reported symptoms, for example nausea and vomitin g, were recorded from two days prior to the onset (Day -2), during infusion , and two days after the end of the infusion (Day +2). In Cycle B, blood wa s drawn at home at Day -2, and at Day 0 in the hospital prior to infusion o nset, thus using a quasi-experimental variation of the CS content of the en vironment. Immune parameters valid for tumor defense and cytotoxic competen ce (natural killer cell activity [NKCA], plasma interleukin [IL]-1 beta, IL -2, IL-10, interferon [IFN]-gamma, tumor necrosis factor [TNF]-alpha) and c ortisol were measured. Results: ANV was reported by 7 patients in at least one cycle. In Cycle A, ANV was positively associated with emetogenity of ch emotherapy. Features of ANV-duration and occurrence-tended to be positively associated with those of posttreatment nausea and vomiting. AN increased a s infusion onset time approached. NKCA and IFN-gamma increased from home to hospital, independent from cortisol level. The NKCA increase was predomina ntly observed in patients with ANV. Conclusions: ANV in pediatric patients showed features of a CR. Immune parameters were sensitive to the CS content of the environment, predominantly in patients with ANV. This is consistent with the manifestation of multiple CRs. (C) 2000 Academic Press.