In recent years, with eligibility for newer drugs and clinical trials highly dependent on kidney function, it has been recognized that CKD is an important aspect of the cancer patient's care. CKD can affect the bioavailability of the cancer treatment, leading to under-dosing, which affects treatment outcome (21). Conversely, the cancer treatment may lead to further renal injury and therefore progressive CKD, limiting further treatment options. With the emergence of targeted therapies and the associated prolonged survival, it has become evident that there is an associated increased risk of renal impairment. This is most evident in patients with renal cell cancer (RCC) who have only one kidney (22, 23). A few large-scale observational studies in Europe have systematically examined the prevalence of CKD among patients with solid tumors. The Renal Insufficiency and Anticancer Medications (IRMA)-1 and-2 are French national observational studies which included about 5,000 cancer patients each (4,684 patients in IRMA-1 and 4,945 in IRMA-2), representing mainly breast, colorectal, lung, ovarian, and prostate cancers (1, 2). About half of the patients in each trial had nonmetastatic disease, and none of them were on dialysis at the time of enrollment. The mean patient ages were 58.1 in IRMA-1 and 59.4 years in IRMA-2. Kidney functions of the patients in these cohorts were assessed with the abbreviated Modification of Diet in Renal Disease formula (aMDRD). The investigators showed that 52.9% of the patients in IRMA-1 and 50.2% of the patients in IRMA-2 had decreased estimated glomerular filtration rate (eGFR) of <90 mL/min/1.73 m 2. CKD stage 3 or higher (eGFR <60 mL/min/1.73 m 2) was observed in 12% of