The Renal Insufficiency and Anticancer Medications (IRMA) study is a French national, observational study, which demonstrated the high prevalence of abnormal renal function in a population of 4,684 solid tumour patients, treated in 15 cancer centers. Among them, 7.2% had a SCR level ≥ 110 mmol/L. In the 1,898 patients with breast cancer, only 31 patients (1.63%) had a SCR level ≥ 110 mmol/L. Nevertheless, respectively 51.8 and 50.8% had a creatinine clearance estimated with the Cockcroft-Gault and aMDRD formulae, below 90 mL/min. Even if the most used medications (anthracyclins, taxanes, trastuzumab, hormone therapies) are not nephrotoxic, these results are important because bevacizumab modifies the need for renal management. In case of renal insufficiency, some other treatments such biphosphonates IV, capecitabin and platin salts need drug dosage adjustment or interruption.