Immunologic mediators of outcome for irradiated oropharyngeal carcinoma based on human papillomavirus status. 
To investigate the prognostic value of pre-treatment immune parameters including white blood cell count (WBC) and circulating lymphocyte count (CLC) among patients with oropharyngeal carcinoma treated by radiation therapy.  A total of 136 consecutive patients were treated by radiation therapy for locally advanced (stage III/IV) squamous cell carcinoma of the oropharynx with known human papillomavirus (HPV) status.  Medical records were reviewed to identify patients with documented pre-treatment laboratory bloodwork.  The Kaplan-Meier method and linear regression models were used to evaluate the association between pre-treatment CBC and CLC values with survival endpoints.  One hundred and eleven patients satisfied inclusion criteria.  Median age was 62 years (range, 22-91).  Eighty-four patients were HPV-positive (76%) and 27 (24%) were HPV-negative.  There was no difference in WBC and CLC mean values at baseline between HPV-positive and HV-negative (p > 0.05, for both).  Trends were detected in the HPV-positive cohort favoring patients with higher CLC, with respect to 2-year local-regional control (93% vs. 82%, p = 0.06) and distant control (88% vs. 82%, p = 0.10) using the median CLC as cut-off.  HPV-positive patients with CLC values in the lowest quartile had inferior local-regional control compared to those in the upper 3 quartiles (69% vs. 89%, p = 0.01).  Low pre-treatment CLC was correlated with local-regional recurrence and distant failure among HPV-positive patients.  These associations were not observed in the HPV-negative cohort.