Risk and prognosis of cancer in patients with nephrotic syndrome.
BACKGROUND
Nephrotic syndrome may be a marker of occult cancer, but population-based studies of this association are lacking. Therefore, we examined the risk and prognosis of cancer in patients with nephrotic syndrome.


METHODS
We conducted this population-based cohort study in Denmark, including all individuals diagnosed with nephrotic syndrome between 1980 and 2010 without a preceding cancer history. We computed the 5-year risk of cancer accounting for competing risk by death and standardized incidence ratios (SIRs) of cancer in patients with nephrotic syndrome relative to the general population. We compared the 5-year mortality for patients with cancer after nephrotic syndrome with that for a cancer cohort without a history of nephrotic syndrome using Cox regression adjusted for age, gender, and comorbidity.


RESULTS
Of 4293 individuals with nephrotic syndrome, 338 developed an incident cancer during a median follow-up of 5.7 years. The 5-year risk of any cancer was 4.7% in patients with nephrotic syndrome, a 73% increased risk (SIR, 1.73; 95% confidence interval [CI], 1.55-1.92). The association was most pronounced for lung cancer, kidney cancer, lymphoma, and multiple myeloma. It was highest within 1 year of nephrotic syndrome diagnosis (SIR, 4.49; 95% CI, 3.68-5.42), but remained increased beyond 1 year (SIR, 1.34; 95% CI, 1.17-1.53). The 5-year mortality after cancer was 68.5% in patients with cancer with nephrotic syndrome and 63.4% in the cancer comparison cohort (adjusted hazard ratio, 1.20; 95% CI, 1.02-1.42).


CONCLUSIONS
Nephrotic syndrome is a marker of occult solid tumors and hematologic malignancies and is associated with a worsened cancer prognosis.
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: cfc@clin.au.dk.
Christian F
CF
Christiansen
Departments of Medicine and Community and Family Medicine and the Norris Cotton Cancer Center, Dartmouth Medical School, Hanover, NH.
Tracy
T
Onega
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
Claus
C
Sværke
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
Dóra
D
Körmendiné Farkas
Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark.
Bente
B
Jespersen
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; Department of Medicine, University of North Carolina, Chapel Hill.
John A
JA
Baron
Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
Henrik Toft
HT
Sørensen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003718:Denmark / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology / Q000401:mortality; D009404:Nephrotic Syndrome / Q000209:etiology*; D011379:Prognosis; D016016:Proportional Hazards Models; D012042:Registries; D012307:Risk Factors
Cohort studies; Mortality; Neoplasms; Nephrotic syndrome; Prognosis; Risk