Patients who undergo radical cystectomy (RC) for bladder cancer are at increased risk of dying from the malignancy if they have blood type A rather than O, a study found.

In a retrospective study of 2,086 patients with urothelial carcinoma (UC) of the bladder treated with RC, a team at Mayo Clinic in Rochester, Minn., led by Boris Gershman, MD, found that non-O blood type was associated with significantly worse 5-year recurrence-free survival and cancer-specific survival compared with O blood type (65% vs. 69% and 64% vs. 70%, respectively). 

On multivariate analysis, blood type A was independently associated with a significant 22% increased risk of death from bladder cancer compared with blood type O, the researchers reported online ahead of print in Urologic Oncology. Blood types B and AB were not associated with bladder cancer-specific mortality compared with blood type O. The study, which the researchers believe is the first to demonstrate an association of blood type with mortality following RC, found no significant association between blood type and disease recurrence and all-cause mortality.

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“ABO blood type represents an appealing prognostic marker given its universal availability and simplicity,” Dr. Gershman told Renal & Urology News. “While it has previously been associated with oncologic outcomes for a number of malignancies, its potential prognostic utility for patients undergoing radical cystectomy has been understudied. We found that non-O blood type, particularly blood type A, was independently associated with an increased risk of cancer-specific mortality among patients undergoing radical cystectomy for urothelial carcinoma of the bladder, even after adjusting for a variety of clinicopathologic features.”

The study’s findings have several implications. “From a clinical standpoint, ABO blood may hold value in risk-stratification to identify patients who may benefit from more aggressive treatment and/or altered surveillance regimens,” Dr. Gershman said.

In addition, he said the findings are provocative with respect to the biologic mechanisms underlying the association of ABO blood type with oncologic outcomes, particularly in light of prior studies suggesting a potential role for ABO blood type in tumor immunology.

The researchers acknowledged that the study was limited by its retrospective design and selection bias, as all subjects underwent RC. “Therefore, although our findings may be used for prognostication among patients undergoing RC, these data cannot be extrapolated to predict the association between blood type and cancer biopsy for all patients with UC of the bladder.”

Previous studies have identified ABO blood type as a prognostic oncologic marker and found associations between blood type and outcomes for various urologic and non-urologic malignancies, the authors observed. Additionally, studies have shown that ABO blood group antigens are located on chromosome 9q34, an area frequently deleted in bladder cancer.

The study by Dr. Gershman and his colleagues included 913 (44%), 881 (42%), 216 (10%), and 76 (4%) patients with blood type O, A, B, and AB, respectively. The median post-RC follow-up among survivors was 11 years.

In a previous retrospective study of 931 patients with non-muscle invasive bladder UC treated with transurethral bladder resection, Tobias Klatte, MD, of the Medical University of Vienna in Austria, and colleagues found that patients with blood type O had significantly increased risks of disease recurrence and progression compared with other blood types, according to a paper published in The Journal of Urology (2014;191:1238-1243).

Furthermore, in a separate retrospective study of 7,906 patients undergoing RC for UC of the bladder, Dr. Klatte and colleagues found no independent association between ABO blood type and mortality, according to findings published in Urologic Oncology (2014;32:625-630).

“The somewhat contrasting results to the findings of our present series may reflect underlying differences between the study populations,” Dr. Gershman’s group stated. “Indeed, we noted that the association of blood type with outcome was particularly evident among patients with organ-confined disease.”

In the study by Dr. Klatte’s group, nearly 25% of patients had pN+ disease and about 42% had pT3/T4 disease, Dr. Gershman and colleagues pointed out.