A Low Systemic Inflammatory Response Index Is Associated With Improved Survival in Adenoid Cystic Carcinoma Patients.

BACKGROUND

Predicting the long-term survival in adenoid cystic carcinoma (ACC) patients remains challenging. Inflammatory cell-based indices are emerging as prognostic indicators of oncology.

PURPOSE: This study aimed to determine the associations between the preoperative systemic inflammatory response index (SIRI) and the systemic immunoinflammatory index (SII) and the 10-year survival rates in patients with ACC of the head and neck (ACCHN).

STUDY DESIGN, SETTING, SAMPLE: This retrospective cohort study comprised ACCHN patients treated at the Chinese People's Liberation Army General Hospital between November 2003 and December 2020.

PREDICTOR VARIABLE: The inflammatory response, assessed using the SIRI and SII, was the predictor variable. The optimal cutoff values were based on the maximum Youden index values (sensitivity ＋ specificity－1). The patients were divided into two groups each, based on the SIRI (low, ≤ 0.15) and (high, > 0.15), and SII (low, ≤ 562.8 and high, > 562.8) values.

MAIN OUTCOME VARIABLE(S): Overall survival (OS), or the number of days, weeks, or months between treatment initiation and death (or the last follow-up date), was the primary outcome variable.

COVARIATES: The covariates were classified as demographic (age, gender, body mass index), medical (hypertension, diabetes), inflammatory (neutrophils, lymphocytes, monocytes, platelets, lymphocyte-monocyte ratio, platelet-lymphocyte ratio, neutrophil-lymphocyte ratio), and perioperative (tumor stage, lymph node metastasis, tumor size, treatment type).

ANALYSES: Descriptive, univariate, and multivariate Cox proportional risk regression analyses were performed to determine whether the SIRI and SII were independent prognostic factors for OS. Kaplan-Meier survival curves and log-rank tests were used to determine their associations with the OS.

RESULTS

The study sample comprised 162 patients (mean age, 52 ± 14; males, 39.5%). The median follow-up time was 6.81 ± 0.23, and the 10-year OS rate was 7.68 ± 0.25. The low and high SIRI groups comprised 109 and 53 patients, while the low and high SII groups comprised 116 and 46 patients, respectively. SIRI was identified as a prognostic factor (P < .01; hazard ratio, 2.45; 95% confidence interval, 1.35-4.45).

CONCLUSION AND RELEVANCE: The SIRI has the advantages of reproducibility, convenience, noninvasiveness, and affordability, making it a promising prognostic inflammatory index for patients with ACCHN.