Cancer Incidence in People With Glomerular Disease: A Population-Level Study.

RATIONAL &

OBJECTIVE

People with glomerulonephritis (GN) may be at an increased risk of cancer, but existing studies have not accurately clarified the cancer risk in patients with GN. A better understanding of these risks may inform cancer screening strategies and identify potentially modifiable risk factors. This study identified risk factors for cancer among Canadian patients with GN.

STUDY

DESIGN

Retrospective observational cohort study.

SETTING &

PARTICIPANTS

Adults with diagnosed GN (n = 4,039) identified using a centralized pathology registry in British Columbia, Canada, between 2000 and 2020.

EXPOSURE: Known cancer risk factors, including age, sex, ethnicity, smoking, alcohol abuse, obesity, diabetes, dyslipidemia, hypertension, and cardiovascular disease as well as GN-related potential risk factors, including GN disease type, estimated glomerular filtration rate (eGFR), and level of proteinuria.

OUTCOME: All-cause cancer, excluding non-melanoma skin cancer.

ANALYTICAL APPROACH: Standardized incidence ratios (SIRs) were calculated using an age- and sex-matched general population. The time to the first cancer event was modeled using a cause-specific hazards model, with death considered as a competing event.

RESULTS

The mean age of the cohort was 51 years, and 52% of the participants were male. During a median of 7.8 years of follow-up, 384 patients (9.5%) developed de novo cancer. The 20-year cancer risk was 23%, with an incidence rate 30% higher than the general population (SIR, 1.3 [95% CI, 1.2-1.4]). The risk was most pronounced in patients younger than 40, almost 3-fold higher than in the general population (SIR, 2.9 [95% CI, 1.6-4.6]). Significant increases in cancer incidence were observed for lymphoma (SIR, 3.5), kidney (SIR, 2.6), colorectal (SIR, 2.4), and lung cancers (SIR, 1.5). Elevated risk was observed both before and after the onset of end-stage kidney disease. Age, male sex, baseline eGFR, and GN disease type were independently associated with cancer risk.

LIMITATIONS: The lack of immunosuppression data.

CONCLUSIONS

Patients with GN have a substantially increased risk of cancer compared with the general population, particularly younger patients who are typically excluded from current screening programs. These findings suggest the need to raise awareness of the cancer risk among people with GN and may inform the further development of tailored cancer screening and prevention strategies, especially among younger adults with GN.

PLAIN-LANGUAGE SUMMARY: People with glomerulonephritis (GN) are thought to be at an increased risk of cancer, but previous studies had limitations that limited the accuracy of the cancer risk estimates in this population. This study of 4,039 patients with GN found the incidence of cancer to be 30% higher than in the general population. Among patients under 40 years of age, the risk was nearly 3-fold. The types of cancers at increased risk were colorectal, lung, kidney, and lymphoma. These findings highlight the need to raise awareness of cancer risk in patients with GN and may inform further development of targeted screening and prevention strategies, particularly among younger adults.