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

Background. Severe treatment-related lymphopenia occurs commonly in many cancers and is associated with early tumor progression. Data are lacking as to whether this occurs in squamous cell head and neck cancer.

Methods. Serial total lymphocyte counts were retrospectively reviewed in patients with newly diagnosed squamous head and neck cancer undergoing chemoradiation and associated with treatment outcomes.

Results. The median baseline total lymphocyte count in 56 patients was 1660 cells/mm3, which fell by 73% to 445 cells/mm3 2 months after initiating chemoradiation (p < .0001). Human papillomavirus negative (HPV-) patients with a total lymphocyte count <500 cells/mm3 at 2 months had significantly earlier disease progression than those with higher total lymphocyte counts (hazard ratio [HR], 5.75; p 5 .045).

Conclusion. Baseline total lymphocyte counts were normal, but at 2 months approximately 60% of patients had severe treatment-related lymphopenia regardless of HPV status. Severe treatment-related lymphopenia in HPV- patients is independently associated with earlier disease progression. Prospective studies are needed to confirm these findings, which suggest that immune preservation is important in this cancer.