COMMENTARY

Quantifying Cancer Risk in Patients With Glomerular Diseases

Tejas P. Desai, MD

Disclosures

May 11, 2018

Nephrology is often plagued by research studies that look at large databases. These observational studies dot the research landscape because they are relatively easy to perform and allow researchers to test several hypotheses concurrently. Although such studies have numerous limitations, they are not all unworthy of one's attention.

Researchers in Denmark recently published a particular observational study that might fit the bill of a worthy observational study.[1] It is known that many glomerular diseases are associated with cancer, although the exact prevalence and incidence of various forms of cancer associated with a particular glomerular lesion is not well defined. Using four large national databases, the researchers quantified the risk of having or developing various cancers on the basis of the type of glomerular lesion found and the time elapsed between glomerular disease diagnoses.

The Study

Denmark, like many countries, has maintained a variety of health-related databases. For this study, the researchers first analyzed the number and type of glomerulonephritis (GN) diagnosed through renal biopsy by inspecting the Danish Renal Biopsy Registry (up to 1999) and then the Danish Renal Biopsy Registry and the National Pathology Data Bank (from 2000 onward). Three decades of data were analyzed (beginning in 1985) to identify all patients with a biopsy-proven diagnosis of GN. Patients in both registries were listed according to their national patient identifier. This identifier was used to cross-reference the third database, the Danish Cancer Registry, to determine the risk of developing various forms of cancer on the basis of the type of GN.

Patients were subdivided into years before and years after GN diagnosis (0-1 year, 1-3 years, 3-5 years, and 5-10 years pre- and post-renal biopsy). The fourth large database used, the Nordic Cancer database (NORDCAN), was used to estimate age- and sex-matched cancer risk in the general population. Perhaps as a testimony to the relatively rarity of a diagnosis of GN, despite using three large databases to acquire patient-specific data, only 5594 patients were included in this observational investigation.

Study Outcomes

One should first note that 36% of all patients diagnosed with GN were already known to have cancer. Of patients whose GN could be classified, the individuals with the greatest prevalence of any cancer diagnosis were those with membranoproliferative GN (risk ratio, 3.1; 95% confidence interval, 1.9-4.7), followed closely by endocapillary GN (risk ratio, 3.0). The analysis indicates that the year before and up to 3 years after GN diagnosis are the times with the highest likelihood of cancer diagnosis. For such diagnoses as minimal change disease, mesangial proliferative GN, and focal segmental glomerulosclerosis, the highest incidence of cancer diagnosis occurs within the first year of diagnosis and then again 5 years later. When all of the data are combined, the greatest incidences of cancer diagnosis occur 1 year before and 1 year after GN diagnosis.

Analysis of the various databases also allowed stratification of cancer type by time of GN diagnosis. Multiple myeloma had the highest incidence of diagnosis 1 year before and 1 year after diagnosis of GN. Of note, nonmelanomatous skin cancer had the highest incidence of diagnosis at any interval before or after GN diagnosis, although the baseline incidence levels may already be high owing to the relatively all-white study population.

Viewpoint

Overall, this is a great observational study. The data should help refine the order and priority of cancer screening on the basis of renal biopsy findings and the time of GN diagnosis. I recognize that the data may not result in a replacement of the cancer screening guidelines put forth by the US Preventive Services Task Force; the Denmark data focus on white patients with GN. Such data have the potential to create a foundation on which the nephrology community can begin to customize its cancer screening protocols for our unique patient population.

Follow Tejas P. Desai, MD, on Twitter: @nephondemand

Follow Medscape Nephrology on Twitter for more nephrology news: @MedscapeKidney

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as:

processing....