Prognostic significance of the preoperative systemic immune‐inflammation index in patients with oral cavity squamous cell carcinoma treated with curative surgery and adjuvant therapy

Objectives To investigate the prognostic value of the preoperative systemic immune‐inflammation index (SII) in patients with oral cavity squamous cell carcinoma (OC‐SCC) treated with curative surgery followed by adjuvant radiotherapy (RT) or chemoradiotherapy (CCRT). Materials and Methods We retrospectively reviewed the clinical records of patients with OC‐SCC who received surgery and postoperative adjuvant RT/CCRT between January 2005 and December 2012. Blood samples were drawn in the 2 weeks preceding surgery. SII was calculated by multiplying the absolute neutrophil and platelet counts, and then, divided by the absolute lymphocyte count, and its optimal cutoff value was identified using the Youden’s index. The study endpoints included overall survival (OS), local control (LC), regional control (RC), and distant control (DC). Results The study sample consisted of 993 patients (58.8% of them treated with CCRT). The optimal cutoff value for SII was 810.6. A total of 347 (34.9%) study participants had high preoperative SII values. After allowance for potential confounders in multivariable analysis, high SII values were independently associated with less favorable DC (adjusted hazard ratio [HR] = 1.683, p = 0.001) and OS (adjusted HR = 1.466, p
The SII is defined as platelet × neutrophil/lymphocyte counts. Increased SII values predict poor distant control and overall survival in patients with oral cancer treated with curative resection and adjuvant RT/CCRT. Owing to the higher risk of systemic failure in this patient group, a tight follow‐up surveillance schedule or adjuvant systemic treatment may be advisable pending independent confirmation of our data.