With a diagnosis of breast cancer, treatment and remission are only the first step on a long journey. Even patients whose cancer was caught in its earliest stages require long-term monitoring to protect against the return of the disease. But not all patients run the same risk of recurrence, and much like treatment, monitoring shouldn’t be a one-size-fits-all strategy. So how can we decide which patients to treat more aggressively, and which to monitor more closely after treatment? One metric useful in other types of cancers is the neutrophil-to-lymphocyte ratio (NLR) – but its utility in breast cancer has thus far been uncertain. Studies conducted in women of Asian descent, who generally have more favorable odds of survival than those of other ethnicities, have yielded inconclusive results. As a result, a team of researchers from Italy spent 15 years monitoring 300 white women diagnosed with stage I or II breast cancer to determine whether or not a high NLR is associated with poorer disease-free survival. “It has been reported to be able to predict prognosis in a variety of solid malignancies,” says Michele Orditura, lead author of the resulting paper (1). “However, evidence is scarce and controversial with regard to breast cancer. Therefore, we sought to determine whether NLR could be useful as a prognostic indicator in early breast cancer.”
Based on pre-treatment blood counts, his team stratified patients into low-NLR (≤1.97) and high-NLR (>1.97) groups. At each subsequent checkup (one, three, six, nine, 12 and 15 years after treatment), patients in the low-NLR group showed better disease-free survival than those in the high-NLR group (see Figure 1). The researchers also searched for other factors that potentially influence survival and identified two: a premenopausal state, and the presence of cancerous cells in axillary lymph nodes. Each of these, along with NLR, is independently associated with a patient’s risk of recurrence. But what’s the mechanism behind the ratio? “We can only speculate on the biological meaning of NLR at the moment,” says Orditura. “In simple terms, NLR may reflect both the role of systemic inflammation in favoring development of metastasis and the inability of the immune system to fight cancer cells.”
Although this observational study can only highlight the correlation between NLR and recurrence, Orditura hopes that it may one day guide treatment and monitoring plans. “Ideally, NLR evaluation should help physicians choose the most appropriate treatment in the individual patient in order to improve survival.”
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References
- M Orditura et al., “Neutrophil to lymphocyte ratio (NLR) for prediction of distant metastasis-free survival (DMFS) in early breast cancer: a propensity score-matched analysis”, ESMO Open, 1, e000038 (2016).