The effect of the history of tonsillectomy on the pathological and clinical features of breast cancer patients

Evidence is growing that the history of tonsillectomy may be a risk factor for breast cancer. The aim of this study was to investigate the effect of tonsillectomy history on the pathological and clinical features of breast cancer patients. The study included 200 patients who had a history of tonsillectomy and 400 patients who had not a history of tonsillectomy who were followed up in Hacettepe University Oncology Hospital between 2005 and 2020 due to breast cancer. Demographic and clinicopathological features of the patients were recorded. In addition, tumor tissues of a group of 34 patients (19 with and without tonsillectomy history) were assessed for presence of tumor infiltrating lymphocyte (TIL), which is known to be predictive and prognostic in breast cancer. For this purpose, CD4 and CD8 expression were evaluated immunohistochemically. Patients in the control and tonsillectomy group were selected equally according to their age and molecular subtypes in the large sample group. The frequency of perineural invasion of the control group was found to be significantly higher (30.3 vs 8.9 p <0.01) and the clinical and pathological features of the groups were similar. The median disease-free survival times (101.0 vs. 105.7 months, p = 0.17) and median overall survival times (103.4 vs. 106.4 months, p = 0.177) of the control and tonsillectomy group were similar. In the subgroup that was examined immunohistochemically, the mean number of CD4 + T cells of the control group was calculated as 62.40 (± 69.60) and 41.05 (± 27.18) of the tonsillectomy group, and there was no statistically significant difference between the number of cells in the two groups (p = 0.115), in the same way, the average CD8 + T cell number of the control group was calculated as 72.07 (± 86.44), tonsillectomy group as 40.95 (± 34.10), and there was no significant difference between the cell number of the groups (p = 0.066). When the number of CD4 + and CD8 + T cells of both groups was examined graphically, it was found that the number of cells was lower in the tonsillectomy group compared to the non-performed group, although it was not statistically significant. The absence of statistical significance was evaluated due to insufficient number of patients. As a result, tonsillectomy may cause a decrease in TIL count in patients with breast cancer. Given that TILs have become the target of developing immunotherapy, a history of tonsillectomy may have predictive value.