BCOP Updates 2025: Using Cystatin C to Evaluate Kidney Dysfunction in Patients with Malignancy & Caring for Pregnant Patients with Malignancy

Creatinine is a widely available biomarker utilized in estimating glomerular filtration rate (GFR). Despite its universal application, creatinine concentration is confounded by many factors including but not limited to reduced muscle mass, advanced age, protein intake, and administration of anticancer therapies that inhibit multiple solute carrier (MSC) transporters limiting its utility as a reliable measure of renal function in select patients with malignancy. While the pathogenesis of renal toxicity associated with traditional chemotherapy and vascular endothelial growth factor inhibitors are well described in the literature, the mechanism of creatinine elevation with certain targeted anticancer agents is rarely elucidated in clinical trials, making it challenging for clinicians to discern if the elevation is due to true kidney damage or primarily due to reversible inhibition of renal MSC transporters. While the majority of creatinine is filtered in the kidneys, 10% to 40% of creatinine is cleared via active tubular secretion making it a less ideal biomarker for GFR estimation in patients receiving inhibitors of MSC transporters. Cystatin C is not subject to active renal secretion and is not affected by changes in muscle mass or diet, making it an attractive alternative to creatinine when estimating GFR in select patients.

The first portion of this module describes mechanisms of serum creatinine elevation observed with certain targeted anticancer agents and discusses utility and limitations of Cystatin C as a potential alternative biomarker of estimating GFR in select patients with malignancy.

The second portion of this presentation will discuss epidemiology of cancer occurrence in pregnancy, probable reasons for increasing incidence, and types of cancer that commonly occur. There are many physiological changes that occur during pregnancy to the woman's body that affect therapeutic drug concentrations. Cancer treatment involves several different modalities that may not all be safe during the different stages of pregnancy. Different cancer treatment modalities, including surgery, chemotherapy, radiation, and targeted therapies, will be discussed for each of the trimesters of pregnancy and during breast feeding. In addition to medical therapy, issues related to delay in diagnosis and examples of ethical dilemmas that can arise will be discussed.

Finally, the importance of discussing fertility preservation with pregnant patients will be introduced. It would be incorrect to assume that since the woman is having one child, she does not desire more children. Options for fertility preservation will be briefly reviewed.