The Predictive Value of the Neutrophil-to-Lymphocyte and Platelet-to-Lymphocyte Ratio in Patients with Recurrent Idiopathic Granulomatous Mastitis

Dear Editor,

We read the recent article ''The predictive value of the neutrophil-to-lymphocyte and platelet-to-lymphocyte ratio in patients with recurrent idiopathic granulomatous mastitis '' published by Cetinkaya et al. (1) with great interest. Authors stated that they investigated the relationship between the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and the prognosis of idiopathic granulomatous mastitis (IGM).

We do not agree with the authors' statement which indicated that although the etiology of IGM was unclear, tuberculosis (TB), sarcoidosis, mycotic, and parasitic infections may play a role in the development of the IGM. It is a common fact that granulomatous mastitis (GM) is classified into two according to the underlying etiology; primary (idiopathic) and secondary (specific) GM. Secondary GM is caused by various specific infectious (bacteria, fungi, parasites) and non-infectious diseases (sarcoidosis, Wegener’s granulomatosis, etc.). On the other hand, IGM is characterized by chronic non-caseification (non-necrotizing) granulomatous inflammation which does not have a specific underlying disease. TB should be included in the differential diagnosis in the endemic areas such as Turkey. Besides, TB and other infections have no direct relationship with IGM.

The authors have shown that patients with preoperative NLR ≥5.02 have 9.33 times higher risk of recurrence when compared to patients with NLR<5.02 (p=0.013). We have analyzed this result and calculated the categorical correlation coefficient for this relationship and the Phi coefficient (Ø) was calculated as 0.437 (p=0.005). This shows a positive and strong relationship between the high NLR and the risk of recurrence. The authors have shown that the sensitivity and specificity of high NLR for prediction of recurrences were 62.5% and 84.8%; respectively. The most important part of this analysis is the negative predictive value of high NLR for prediction of recurrence to be 90.3%. In other words, high NLR gives a better idea regarding patients that will not develop recurrence rather than predicting the recurrence of IGM. This theory is supported by the fact that high NLR had a specificity of 84.8% and a positive predictive value of 50.2%.

The authors should have performed a multivariate analysis to determine the independent risk factors for recurrence by using the variables with a p-value <0.1 that was determined in the univariate analysis. However, the authors did not perform any logistic regression analysis. We have used the methodology on the variables expressed in authors’ Table-2 and performed a logistic regression analysis. The only variable that fit the criteria was NLR and the multivariate analysis yielded similar results as the univariate analysis. We were able to show that NLR ≥5.02 was an independent risk factor determining the recurrence in patients with IGM (Logistic regression with backward LR; Wald: 6.49, p=0.011, OR=9.33 95% CI=1.67–52.06).

Recently, NLR is used as a surrogate marker for the systemic inflammatory process. During systemic inflammation, neutrophil counts increase, and lymphocyte counts decrease which increases NLR. For this reason. NLR can be used to predict the severity of the disease in various clinical conditions such as various infectious diseases, cancer, and critically ill patients. In literature, there is only one study analyzing the role of NLR in IGM. Kargin et al. (2) have compared NLR in patients with (n=7) and without (n=52) recurrence and have found that NLR was significantly higher in patients with a recurrence (p<0.001) but they have not performed a ROC analysis to support their observations.