Topic Discussion: Why does OncoNephrology matter?

Cancer affects the kidney in many ways. Education of the cancer specialists is important. Lately I have felt that the "kidney" has been ignored in many ways in the oncology world.

Recently, a review was published in NEJM on cancer survivorship and how long patients with cancer are living and the non cancer related complications. There was no mention of CKD and kidney related complications. Several studies have shown that CKD is an independent factor for mortality and cancer related mortality in cancer patients.  Few of us wrote a letter to the editor raising this concern. The response from the author was that “ CKD has a high mortality and not specific to cancer survivors”. This is an important message for our heme/onc colleagues to understand that CKD can add to the risk for cancer survivors. Having early nephrology care and co-managing and preparing for CKD related complications is important.

Another important ignored concept in Oncology is lack of studies that include patients with low GFR. In a recent analysis published in JAMA, Eighty-five percent of recent trials of therapies for the 5 most common malignancies (published in selected high–impact factor journals) excluded patients with CKD. This proportion exceeds that observed in cardiovascular trials published from 1985 through 2005. This finding is concerning because it was estimated that 32% of deaths among patients with CKD in 2005-2009 were attributable to malignancy. As a result of trial under-representation, patients with CKD may not be considered for cancer therapies that have potential to improve morbidity and mortality.

Also, most trials used serum creatinine or CrCl thresholds to exclude patients, despite data demonstrating that these are sub-optimal measures of kidney function in cancer patients. Given the availability of more accurate and validated methods for estimating kidney function, the oncology drugs trials cannot just rely on creatinine measurements.

Finally, two recent reviews published in NEJM and JAMA on immunotherapy related toxicities failed to mention renal toxicities. Liver and kidney are two organs that are responsible for most drug metabolisms. Ignoring those side effects is probably not a good idea. Space limitations and % incidence of renal incidence being low were cited reasons for not including renal toxicities.

As a renal community, it is important that we respond back and make sure the voice of the nephrologists is heard as more and more novel agents are in the market to treat cancer.