Effect of ABO blood type on mortality in patients with urothelial carcinoma of the bladder treated with radical cystectomy

Abstract

Objective

ABO blood type is an inherited characteristic that has been associated with the prognosis of several malignancies, but there is little evidence in urothelial carcinoma of the bladder (UCB). The purpose of this study was to evaluate the effect of ABO blood type on mortality in patients with UCB treated with radical cystectomy (RC).

Methods

Multi-institutional data from 7,906 patients with UCB treated with RC between 1979 and 2012 were retrospectively analyzed. The effect of ABO blood type on UCB-related mortality was evaluated with univariable and multivariable competing-risks regression models.

Results

ABO blood type was O in 3,728 (47%), A in 2,748 (35%), B in 888 (11%), and AB in 532 (7%) patients. Blood type B was associated with a greater likelihood of lymphovascular invasion (P = 0.010) and positive soft tissue margins (P = 0.008). The median follow-up was 41 months. The 5-year cumulative UCB-related mortality rates for blood type O, A, B, and AB were 29.5%, 30.5%, 33.2%, and 25.8%, respectively. In univariable competing-risks regression, patients with blood type B had worse UCB-related mortality than those with blood type O (P = 0.026) and AB (P = 0.020). In multivariable analysis, however, blood type lost its statistical significance.

Conclusions

Among patients treated with RC, ABO blood type is associated with a statistically significant but clinically insignificant difference in UCB-related mortality. This association was not present in multivariable analysis. Our data therefore suggest no relevant association of ABO blood type with UCB-related prognosis.

Introduction

Urothelial carcinoma of the bladder (UCB) is the leading malignant tumor of the urinary system, with more than 70,000 newly diagnosed cases in the United States annually [1]. At initial diagnosis, approximately three-fourths of patients have non–muscle-invasive UCB, and approximately one-fourth present with muscle-invasive disease. For high-risk and recurrent non–muscle-invasive as well as muscle-invasive UCB, radical cystectomy (RC) and pelvic lymphadenectomy are the treatment of choice [2]. Despite aggressive treatment, mortality rates are high, with approximately 50% of patients succumbing in the first 5 years after the operation [2]. Established prognostic factors for UCB treated with RC include pathological T classification, lymph node involvement, grade, lymphovascular invasion (LVI), and soft tissue surgical margin (STSM) status [3], [4], [5], [6], [7], [8].

The ABO blood type is available for every patient who undergoes elective surgery and represents a potential prognostic biomarker. In North America and Europe, 37% to 44% of the population are blood type O, approximately 42% are A, 10% to 14% are B, and 4% to 6.5% are AB [9]. The corresponding ABO gene is located on chromosome 9q34.1-34.2, an area that is frequently affected in UCB [10], [11]. Studies show that ABO blood group antigen expression within the UCB decreases with grade [12] and may be linked with outcomes [13], [14]. In terms of patients' blood type status, studies conducted several decades ago suggested that blood type O and B are associated with a more unfavorable pathology and possibly worse prognosis, although the differences were clinically small or statistically insignificant [15], [16]. In contrast, data from other malignancies indicate that ABO blood type is significantly associated with stage and survival [17], [18], [19].

We hypothesized that ABO blood type is a prognostic factor in UCB and tested this hypothesis in an international cohort of more than 7,000 patients treated with RC.