O-positive blood type is associated with prolonged recurrence-free survival following curative resection of pancreatic neuroendocrine tumors

Background: The ABO blood group may influence the development and progression of cancer. In particular, the prognosis of patients with blood type O is better for pancreatic adenocarcinoma, although this has not been extensively explored in pancreatic neuroendocrine tumors (PanNET).

Objective: To assess the influence of the ABO and Rhesus blood types on the risk of recurrence in patients who underwent curative intent PanNET surgical resection.

Methods: All consecutive patients operated on for well-differentiated panNET in an expert center from 2003 to 2018 were retrospectively included. Blood group, Rhesus system, demographic and clinical data were collected. The primary endpoint was recurrence free survival (RFS). Factors associated with RFS were explored using Cox proportional hazard models.

Results: Overall, 300 patients (male 43%) were included, median age 54 years old (IQR 45-64). The ABO blood group distribution was similar to that of the French population. There was no association between blood group and tumor features. The median postoperative follow-up was 43.9 months (17.0-77.8). The 5- and 10-year RFS rates were 85 ± 4% and 71 ± 13% in O RhD + patients, versus 72 ± 4% and 63 ± 6% otherwise, respectively (p = 0.035). The O RhD + blood group was associated with a decreased risk of recurrence (HR 0.34, 95% CI [0.15-0.75]), p = 0.007 in multivariable analysis adjusted for age, ki67, functioning syndrome, resection margins, tumor size, lymph node status, oncogenetic syndrome.

Conclusions: After curative-intent surgical resection for PanNET, patients with a non-O RhD + blood group may have an increased risk of recurrence and could benefit from closer follow-up.