Circulating CD4-positive lymphocyte levels as predictor of response to induction chemotherapy in patients with advanced laryngeal cancer.

BACKGROUND Tumor regression after induction chemotherapy (ICT) identifies laryngeal cancers that are responsive to chemoradiation. Patient immune parameters have recently been associated with response to chemotherapy and may identify responding patients. A retrospective analysis was performed to determine if pretreatment, circulating T lymphocyte levels predicted ICT response in patients with advanced laryngeal cancer. METHODS Pretreatment, circulating T lymphocyte subpopulations were correlated with response to therapy and survival. Results were compared with similar data from an identical phase II trial involving patients with oropharyngeal cancer. RESULTS An increased percentage of CD4+ cells predicted response to ICT and suggested improved survival in patients with laryngeal, but not oropharyngeal, cancer. In the combined group of patients, increased CD4 levels predicted response to ICT. CONCLUSION These findings demonstrate the potential importance of the immune system in chemotherapy response and clinical outcome. Differences in findings between patients with advanced laryngeal and oropharyngeal cancer may reflect different cellular immunity function in the patients with human papillomavirus (HPV)-16+ oropharyngeal cancer.