Prognostic value of albumin-to-alkaline phosphatase ratio before radical cystectomy in patients with bladder cancer

Objective To investigate the relationship between preoperative albumin-to-alkaline phosphatase ratio and overall survival (OS) after radical cystectomy of bladder cancer. Methods The clinical date of patients with bladder cancer who underwent radical cystectomy and urinary diversion and confirmed by pathology from Jan 2007 to Dec 2015 were analyzed retrospectively, with 140 cases undergoing laparoscopic surgery and 26 cases undergoing open surgery. There were 148 males and 18 females, aged was 33-85 years, with an average age of (65.1±9.4) years. There were 55 cases of cutaneous ureterostomy, 96 cases of Brick diversion with ileum, and 15 cases of ileal neobladder. The AAPR range 0.03-1.67, with an average 0.62±0.23, and body mass index (BMI) was 16.79-32.65 kg/m2, with an average of (24.00±3.32) kg/m2. There were 33 cases with hydronephrosis and 133 no hydronephrosis, 31 cases with hypertension and 135 cases no hypertension, and 14 cases with diabetes and 152 cases no diabetes. Four cases were classified as grade 0, 65 cases as grade 1, 86 cases as grade 2, and 11 cases as grade 3. Based on the preoperative AAPR(0.62±0.23), they were divided into three groups, with 55 cases in the low AAPR (0.42±0.09)group, 55 cases in the middle AAPR(0.58±0.05)group, and 56 cases in the high AAPR(0.86±0.21)group. Cox proportional hazards regression methodology were used to evaluate the relationship between preoperative AAPR and overall survival. Survival analysis was conducted using the Kaplan-Meier method and compared with the log-rank test. Results 166 patients were followed up for 1-144 months, with a median of 63 months, and 71 cases died and 95 survived. The median serum AAPR level in all cases was 0.59(range 0.03-1.67). Results of univariate Cox regression model revealed that AAPR(HR=0.09, 95%CI 0.022-0.391, P=0.001), high AAPR (HR=0.40, 95%CI 0.216-0.742, P=0.003), age (HR=2.42, 95%CI 1.294-4.531, P=0.006), tumor size (HR=2.11, 95%CI 1.112-4.014, P=0.023), pT3 stage (HR=8.93, 95%CI 3.173-25.114, P<0.001), pT4 stage(HR=10.39, 95%CI 3.110-34.707, P<0.001), pN1 stage(HR=2.80, 95%CI 1.422-5.531, P=0.003), pN3 stage(HR=17.06, 95%CI 2.192-132.863, P=0.007), pathological grade (HR=0.30, 95%CI 0.113-0.817, P=0.019), hydronephrosis (HR=2.36, 95%CI 1.406-3.939, P=0.001), adjuvant chemotherapy (HR=2.66, 95%CI 1.674-4.247, P<0.001)were associated with OS. Compared with patients in the lowest of AAPR, the risk for death in the highest AAPR group decreased about 59%(HR=0.406, 95%CI 0.200-0.822, P=0.012)after adjustment for age, BMI, tumor size, number of tumor, T category, N category, pathological grade, hydronephrosis, ASA level, adjuvant chemotherapy in multiple Cox regression models. Each unit increase in the AAPR was associated with about 80% decreased risk of death (HR=0.199, 95%CI 0.051-0.779, P=0.020)after adjusting for the confounding variables. After adjusting for age, BMI, tumor size, number of tumor, T category, N category, pathological grade, hydronephrosis, ASA level, adjuvant chemotherapy, the curve fitting results showed that with the increase of AAPR, the risk of death decreased and the overall survival prolonged. Consistent with the linear trend test results, the relationship between AAPR and OS is linear. Conclusions AAPR was associated with overall survival of patients who underwent radical cystectomy of bladder cancer. Key words: Urinary bladder neoplasms; Bladder cancer; Albumin-to-Alkaline phosphatase ratio (AAPR); Radical cystectomy; Prognosis