Blood group O in patients with renal cell carcinoma (RCC) is associated with a lower risk of lymph node metastases but a higher risk of bilateral disease, according to researchers. It is not associated with survival.

A team led by Tobias Klatte, MD, of the Medical University of Vienna in Austria reviewed data from 556 patients who underwent surgery for RCC to evaluate the relationship between blood groups and clinical and pathologic variables. Subjects had a median follow-up of 39 months. Blood group O was associated with a significantly lower risk of lymph node metastases (1% vs. 4%), the investigators reported online ahead of print in BJU International. Of 16 patients with positive nodes, 14 (87.5%) had a non-O blood group. In multivariable analysis, patients with a non-O blood group had a 5.8 times increased risk for lymph node metastases compared with those who had blood group O. Of 29 patients with bilateral RCC, 17 (58.6%) had blood group O compared with 193 (36.6%) of 527 patients with unilateral disease.

ABO blood group overall was not associated with RCC prognosis.

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Of the 556 patients, 93 died, 61 from RCC. The five-year overall and cancer-specific survival rates were 75% and 83%, respectively, with no significant difference between blood group O and non-O blood group. The researchers noted that their study did not confirm a previously reported finding of an association between ABO blood group and overall survival. Last year, researchers published study results in BJU International (2012;110 [11 Pt B]:E641-E646) demonstrating that RCC patients with a non-O blood type had a significant 68% increased death risk compared with those who had blood type O. The patient groups did not differ significantly with respect to cancer-specific survival.

Dr. Klatte’s group noted that their study may have been underpowered to detect a significant difference in overall survival. “Since the study population and inclusion criteria differed considerably, the two studies should be interpreted as complementary, not oppositional,” they wrote.

Additionally, Dr. Klatte and his colleagues observed no association between blood group and age, gender, body mass index, T stage, M stage, histologic subgroup, or Charlson comorbidity index.

“The mechanisms through which blood group may influence cancer risk and progression are largely unknown,” the authors pointed out. Blood group antigens may affect cell adhesion, membrane signaling, and immune surveillance, they stated, and this in turn may influence cancer development and progression.

Previous research has shown that the risk of pancreatic cancer is increased in patients with a non-O blood group and that a non-O blood group decreases the risk of skin cancer. Other studies have found no association of blood group with cancer risk.

Dr. Klatte and his colleagues acknowledged some study limitations, including the retrospective design and the relatively small number of patients and short follow-up.