ABO blood groups, rhesus types, and colorectal adenocarcinoma. A retrospective study of 747 cases.

The distribution of ABO blood groups and Rh types was studied retrospectively in 747 patients with single adenocarcinomas of the large intestine. The distributions were similar to those of healthy blood donors. Rh- patients had a more favourable stage distribution than Rh+ patients. The proportion of patients with localized disease was higher for Rh- patients than for Rh+ patients (66% versus 46%), whereas metastases into regional lymph nodes were more common among Rh+ patients (23% versus 9%). The observed relationship between Rh type and stage distribution suggests that Rh+ patients with colorectal cancer are less protected against tumour spread than Rh- patients, especially with regard to regional lymph node metastases.