The prevalence of TSAT<20% was computed in two subgroups of patients receiving early treatment of the disease: either adjuvant or neo-adjuvant treatment.Results: A total of 443 patients with a documented curative treatment were analysed: 300 (67.7%) received an adjuvant treatment and 143 (32.3%) a neo-adjuvant treatment, consisting in chemotherapy in most cases. TSAT<20% was found in 47.1% (41.5-52.8) of patients with adjuvant treatment and 51.0% (42.9-59.1) of patients with neo-adjuvant treatment. Among iron-deficient patients according to ESMO definition (based on both ferritin level and TSAT), 85.8% and 90.1% of patients had a TSAT <20%, in the two treatment groups respectively. Conclusions:The prevalence of ID in cancer patients receiving adjuvant or neoadjuvant treatment was high, and of the same magnitude than that reported in patients under metastatic treatment. Early diagnosis and treatment of ID in those patients at early-stage disease might limit the occurrence of anaemia and improve quality of life. TSAT < 20% as the sole criterion for defining ID had a high sensitivity and might be considered for ID diagnosis.Clinical trial identification: NCT03924271.Editorial acknowledgement: We thank Valérie Briand (IQVIA) for reviewing the abstract.Legal entity responsible for the study: Vifor Pharma Group.