POWER4 Data: Anemia Flags Risk but Isn’t a Confirmed Driver of Recurrence

The multicenter POWER4 cohort analysis reports that preoperative anemia and perioperative red blood cell transfusion associate with worse disease-free survival on univariable analysis, but associations attenuate with multivariable adjustment, supporting anemia as a vulnerability marker rather than a proven independent driver of recurrence.

Among 386 patients, 47% had preoperative anemia and 28% received perioperative transfusion; unadjusted DFS event rates ranged from 13% to 38% across exposure groups and showed marked univariable differences. Multivariable Cox models attenuated those effects and removed statistical significance. The models adjusted for age, ASA ≥ III, MUST high-risk nutritional status, TNM stage, and moderate-to-severe postoperative complications. A causal mediation analysis estimated transfusion explained ~26% of the anemia–DFS association, without statistical significance. Residual confounding (e.g., tumor biology or inflammatory status) may partly explain attenuation.

For multidisciplinary teams, it's important to prioritize preoperative anemia workup and integrate PBM pathways into perioperative planning, using anemia as a flag for vulnerability and higher perioperative risk. In addition, balance transfusion decisions to secure immediate patient safety while acknowledging that current cohort evidence does not establish a causal oncologic effect. Prospective interventional studies remain needed to test whether targeted anemia correction or altered transfusion practices change recurrence risk.