The neutrophil-to-lymphocyte ratio (NLR) may not be as reliable as previously believed at predicating cancer progression and which drugs will be the most effective, according to results published in Cancer.
Risk stratification is a significant challenge in bladder cancer. A number of prior studies have linked elevated NLR with worse overall survival after patients with bladder cancer undergo cystectomy. It has also been reported that NLR correlates with the amount of cancer found during surgery, which led many to suspect that a blood test might help to predict the patients most likely to benefit from pre-surgery chemotherapy to shrink their tumors.
In an unplanned secondary analysis of the SWOG 8710 trial, researchers led by Eric Ojerholm, MD, University of Pennsylvania, Philadelphia, assessed how NLR levels affected overall survival in patients with bladder cancer who received cystectomy with or without neoadjuvant chemotherapy (NAC) by analyzing prospectively collected complete blood counts.
Of 317 total patients included in the original trial, researchers identified 230 for a prognostic analysis of NLR to see if it could serve as a predictor of how long patients would live after curative treatment. Another 263 patients were included in a predictive analysis designed to determine whether NLR could predict patients most likely to respond to chemotherapy. Medium follow-up was 18.6 years.
Overall, there were 172 and 205 deaths in the prognostic and predictive cohorts, respectively. Researchers found that, in a multivariable analysis, NLR was not a prognostic indicator of overall survival (hazard ratio [HR], 1.04; 95% confidence interval [CI], 0.98-1.11; P = .24), nor was it capable of predicting the overall survival benefit derived from NAC (HR, 1.01; 95% CI, 0.90-1.14; P = .86).
Researchers concluded that, despite evidence from previous studies, their findings indicate that NLR is neither a prognostic nor predictive biomarker for overall survival in bladder cancer.
In commenting on why prior studies may have supported NLR as a biomarker, Dr Ojerholm pointed to several factors beyond methodology and statistical design.
"There's also the problem of publication bias. Sometimes authors won't submit negative results, and sometimes journals won't accept them. That could be a real issue as NLR research continues,” Dr Ojerholm explained. "Yet this study does raise questions about NLR for bladder cancer and we need more evidence before using this biomarker in clinical practice."
