While elevated concentrations of pro-inflammatory cytokines IL-6 and IL-1β were observed in patients with poorer response speed performance and perceived cognitive disturbances receiving chemotherapy for breast cancer, IL-4 may be protective against chemotherapy-associated cognitive impairment, a new study published online early in the journal Annals of Oncology has shown.

“This study is important because cytokines would potentially be mechanistic mediators of chemotherapy-associated cognitive changes,” the study authors said.

For the study, researchers sought to investigate whether an association exists between pro-inflammatory cytokines and post-chemotherapy cognitive impairment in patients with breast cancer.

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Researchers enrolled 99 chemotherapy-receiving patients with breast cancer. Pro-inflammatory cytokine concentrations were assessed prior to chemotherapy, 6 weeks after, and 12 weeks after chemotherapy initiation. 

Questionnaires and assessments were used to evaluate patients’ self-perceived cognitive disturbances, memory, attention, response speed, and processing speed.

Results showed that higher plasma IL-1β was associated with poorer response and speed performance (P = 0.023), and an increased concentration of IL-4 was associated with better response speed performance (P = 0.022).

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Researchers found that higher concentrations of IL-6 and IL-1β were associated with more severe self-perceived cognitive disturbances (P = 0.018 and 0.001, respectively).

The study also showed that patients with higher plasma concentrations of IL-4 was associated with less severe cognitive disturbances (P = 0.022).


  1. Cheung YT, Ng T, Shwe M, et al. Association of pro-inflammatory cytokines and chemotherapy-associated cognitive impairment in breast cancer patients: a multicentered, prospective, cohort study. Ann Oncol. 2015. [Epub ahead of print]. doi: 10.1093/annonc/mdv206.