Exploring the prognostic impact of absolute lymphocyte count in patients treated with immune-checkpoint inhibitors
Michael Conroy, Hazel O’Sullivan, Delwood C. Collins, Richard Bambury, Derek G. Power, Stuart A. Grossman, Séamus O’Reilly
Abstract
BACKGROUND: The role of immune checkpoint inhibitors (ICI) expands but affordable and reproducible prognostic biomarkers are needed. We investigated the association between baseline and 3-month absolute lymphocyte count (ALC) and survival for patients on ICI. METHODS: A retrospective study investigated patients who received ICI July 2014-August 2019. Survival probabilities were calculated for lymphocyte subsets. Univariate and multivariate analyses were performed to investigate risk factors for lymphopenia. RESULTS: cells/L) and no significant difference in PFS or OS to those with normal ALC. However, 31% had lymphopenia at 3 months and significantly shorter OS than those without (9.8 vs 18.3 months, p < 0.001). Those with baseline lymphopenia who recovered counts at 3 months had no difference in PFS (median NR vs 13.0 months, p = 0.48) or OS (22 vs 18.3 months, p = 0.548) to those never lymphopenic. The strongest risk factor for lymphopenia on multivariable analysis was previous radiation therapy (RT). CONCLUSIONS: 3-month lymphopenia is a negative prognostic marker in cancer patients on ICI. Previous RT is significantly associated with lymphopenia.