Despite Positive Studies, Neutrophil-to-lymphocyte Ratio Not Ready for Clinical Use
Neutrophil-to-lymphocyte ratio is an attractive candidate prognostic biomarker for patients with cancer, but mixed study results draw cautions.
Based on readily available clinical data, patient neutrophil-to-lymphocyte ratio (NLR) is an attractive candidate prognostic biomarker for patients with genitourinary and other types of cancer, suggest a spate of recently published studies. But results are mixed and it is too soon for its routine use for patient stratification, researchers cautioned.
Complete blood count (CBC) is a routine clinical exam for patients diagnosed with cancers, and prognostic biomarkers based on such laboratory data would be a welcome addition to patient-stratification criteria.
Recent studies suggest that patients' baseline—and even postoperative—NLRs, (measured by dividing neutrophil counts by lymphocyte counts) might be a prognostic marker of outcomes across several cancer types.1-5
The association of NLR with cancer patients' outcomes is biologically plausible because NLR is a proxy of inflammation processes.
Unfortunately, that also leaves NLR nonspecific to tumor progression that is likely confounded by such comorbidities as metabolic syndrome, diabetes, hypertension, thyroid dysfunction, infection, and other conditions or disorders affecting inflammation—not to mention medications used to manage these conditions.6
“Some people say NLR is a measure of the systemic inflammatory state, and that this could impact cancer progression,” explained Eric Ojerholm, MD, physician in radiation oncology at the Hospital of the University of Pennsylvania in Philadelphia. “Other researchers observed that patients with high levels of neutrophils also had high levels of pro-growth signals [cytokines] for tumors. And low levels of lymphocytes might mean the body's immune system can't respond well to cancer. So a high level of neutrophils plus a low level of lymphocytes (high NLR) could reflect an environment that promotes cancer progression.”
RELATED: Neutrophil, Lymphocyte Ratio May Predict Survival in Head and Neck Cancer
Recent studies indicated that NLR predicted progression, recurrence, and even patient overall survival in genitourinary cancers such as bladder cancer and clear cell renal cell carcinoma.1,2
“Elevated preoperative NLR is associated with poor prognosis in patients with metastatic kidney cancer,” concluded authors of one study.2 “Preoperative NLR is a useful tool, which can predict prognosis, stratify patients for postoperative surveillance, and help guide decisions for therapy.”
But other experts contacted by Cancer Therapy Advisor urged caution.