The association between severe treatment-related lymphopenia and progression-free survival in patients with newly diagnosed squamous cell head and neck cancer.

Abstract

6068 Background: Severe treatment-related lymphopenia (TRL) occurs in 50% of glioblastoma and pancreatic cancer patients and is associated with early death from tumor progression. We sought to determine if similar findings were seen in head and neck squamous cell carcinoma (HNSCC). Methods: Eligible patients for this retrospective study had: 1) HNSCC cancer diagnosed in 2007-2009, 2) good performance status, 3) platinum-based chemoradiation, and 4) follow-up at Johns Hopkins. Serial total lymphocyte counts (TLC), overall survival (OS) and progression-free survival (PFS) were analyzed accounting for known prognostic factors. Results: Fifty-six adults met eligibility criteria: median age: 57 years, female: 21%, HPV+: 61%, surgery prior to chemoradiation: 16%, stage IVA-IVB: 77%, T stage 3-4: 40% and N stage 2b-3: 56%. Changes in TLC are shown below (Table). 14/56 patients (25%) had tumor recurrence and 9 (16%) died of their tumor. HPV+ patients had longer PFS (p=0.01) and OS (p=0.006) than HPV- patients. 10/22 HPV- patients had disease progression and 7 died. HPV- patients who developed grade III-IV TRL two months after beginning chemoradiation had a strikingly higher hazard rate for disease progression than those whose TLC remained higher (multivariate analysis HR 6.2, 95%CI: 1.1-35.2; p=0.039). Too few events occurred in the HPV+ cohort for analysis. Conclusions: TLCs were normal before chemoradiation. However, two months after chemoradiation ~60% of patients had severe TLC regardless of HPV status. HPV- patients with severe TRL were much more likely to have disease progression than those without TRL. Prospective studies are needed to confirm these findings which are similar to those reported in other cancers. Preservation of the immune system during chemoradiation may be important to improving PFS and OS. [Table: see text]