Changes in plasma levels of inflammatory cytokines in response to paclitaxel chemotherapy

Background: Flu-like symptoms are common, early transient side effects of paclitaxel chemotherapy. We hypothesized that these symptoms may be due to release of inflammatory cytokines in response to treatment. The objective of this study was to assess changes in plasma levels of interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12, and TNF-α during chemotherapy and to correlate these changes with musculoskeletal symptoms. Methods: Ninety patients with breast cancer were included; 70 patients received single agent paclitaxel either weekly or every 3 weeks and 20 received FAC (5-FU, doxorubicin, cyclophosphamide) chemotherapy. Fifteen healthy volunteers were included as controls. Cytokines and symptoms were measured before starting therapy, on day 3 and on the last day of one treatment cycle. Results: At baseline, all subjects had measurable levels of IL-8 but only 49% had IL-12, 45% had IL-10, 32% had IL-6, and 21% had IL-1β or TNF-α in their plasma. There was no difference in baseline cytokine levels between cancer patients and the healthy volunteers. Schedule-dependent transient changes in the levels of 3 cytokines were observed in the paclitaxel treated patients. In the every 3-week paclitaxel group, IL-6 and IL-8 increased whereas in the weekly paclitaxel group IL-10 increased significantly compared to baseline. Fatigue and flu-like symptoms were also worse on day 3. In the weekly paclitaxel group, increase in IL-10 level correlated positively with joint pain (p=0.003). In the every 3-week paclitaxel group, increase in IL-8 level correlated positively with flu-like symptom (p=0.008). In the FAC-treated group and among the healthy volunteers none of these cytokines increased significantly. Conclusion: Weekly paclitaxel induces transient increase in IL-10 levels whereas every 3-week higher dose treatments induce IL-8 and IL-6 in the plasma. These changes correlate with joint pain and flu-like symptoms.