Blood transfusions and prognosis in colorectal cancer: long-term results of a randomized controlled trial.

Perioperative blood transfusions may adversely affect survival in patients with colorectal malignancy, although definite proof of a causal relationship has never been reported. We report the long-term outcomes of a randomized controlled trial performed between 1986 and 1991 to compare the effects of allogeneic blood transfusions and an autologous blood transfusion program in colorectal cancer patients. All 475 randomized patients operated upon for colorectal cancer were tracked via a national computerized record-linkage system to investigate survival and cause of death. Kaplan-Meier survival curves were constructed and multivariate Cox regression analysis was performed to study 20 years' overall survival. Colorectal cancer-specific survival was analyzed over the 10-year time period after surgery. The overall survival percentage at 20 years after surgery was worse in the autologous group (21%) compared to the allogeneic group (28%) (P = 0.041; log-rank test). Cox regression, allowing for tumor stage, age, and sex, resulted in a hazard ratio (autologous vs allogeneic group) for overall mortality of 1.24 (95% confidence interval 1.00-1.54; P = 0.051). Colorectal cancer-specific survival at 10 years for the whole study group was 48% and 60% for the autologous and allogeneic group, respectively (P = 0.020; log-rank test). The adjusted hazard ratio was 1.39 (95 confidence interval 1.05-1.83; P = 0.045). At long-term follow-up colorectal cancer patients did not benefit from autologous transfusion compared with standard allogeneic transfusion. On the contrary, the overall and colorectal cancer-specific survival rates were worse in the patients in the autologous transfusion group.

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