Abstract
Background: The association between glomerulonephritis (GN) and cancer has been well known for decades. However, studies evaluating long-term de novo cancer development in patients with GN are limited. This study aimed to evaluate the incidence of cancer development among patients with renal biopsy-proven GN during post-biopsy follow-up and the differences in outcomes according to cancer occurrence. Methods: We conducted a retrospective cohort study of adult patients who underwent renal biopsy at Seoul National Bundang Hospital between 2003 and 2017. After excluding 671 patients who are inappropriate for the analysis, 929 patients were included in the analysis. Data on baseline clinical characteristics, renal biopsy results, and types and doses of immunosuppressant agents used during follow-up were collected from electronic medical records. The incidence of cancer was censored on the date when the first cancer was diagnosed. We evaluated rates of mortality and end-stage renal disease (ESRD) development during follow-up. Results: During a mean follow-up period of 52.4 (range: 1.0–166.7) months, 49 subjects (5.3%) developed de novo cancer. A comparison of clinical characteristics between subjects who did and did not develop cancer revealed that cancer patients were older and had higher comorbidities and immunosuppressant use. Overall, patients with GN had an elevated standardized incidence ratio (SIR) of 7.17 (95% confidence interval (CI): 5.3–9.51) relative to the general population. In particular, the SIR was significantly higher in GNs such as membranous nephropathy (MN), IgA nephropathy, lupus nephritis, and focal segmental glomerulosclerosis. Multivariable Cox proportional hazard model adjusted for confounding variables revealed that patients with a pathologic diagnosis of MN had an increased risk of cancer development, with a hazard ratio of 2.6 [95% CI: 1.32–5.30]. Patients with MN who developed cancer had a significantly higher risk of mortality (hazard ratio: 5.95; 95% CI: 1.36–26.09, P=0.018) than those without cancer, but there was a non-significant difference in ESRD development. Conclusions: Patients with GN without concurrent cancer, particularly those with MN, have significantly higher risks of cancer development and subsequent mortality and should remain aware of the potential development of malignancy during follow-up.
Cancer development and mortality differences in patients with glomerulonephritis after renal biopsy: a single center retrospective cohort study