Background: Primary medical treatment of idiopathic retroperitoneal fibrosis (RPF) increasingly is accepted. However, the optimum treatment strategy is still unclear.
Study design: Case series.
Setting & participants: Single tertiary care referral center. 24 patients with idiopathic RPF treated with prednisone for 1 year, if needed, with (urgent) renal drainage from June 1991 through October 2006.
Outcome & measurements: Clinical improvement, laboratory parameters, repeated computed tomographic (CT) scanning. Treatment was considered successful if the following criteria were met at the end of the 1-year treatment period: significant subjective clinical improvement, (near-)normalization of acute-phase reactants, improvement in renal function with disappearance of ureteral obstruction, and CT-documented mass regression. Recurrence is defined as need for retreatment because of return of signs and symptoms after the 1-year treatment period in patients with initial treatment success.
Results: 22 patients reported significant to complete resolution of symptoms after median treatment duration of 2.0 weeks (0.7 to 3.0). Follow-up showed decreases in erythrocyte sedimentation rate, C-reactive protein level (both P < 0.0001), and serum creatinine level (P = 0.0230) at 6 weeks, which persisted during the treatment period. Repeated CT scanning showed mass regression in 19 patients during the treatment period. Six patients were considered treatment failures, and there were 23 recurrences 10 months (7 to 14) after prednisone withdrawal in 13 of 18 patients with initial treatment success. At the end of follow-up (median, 55 months), 7 patients had impaired renal function; 1 patient reached end-stage renal disease. The mortality rate was 8%.
Limitations: There was no comparison with other treatments.
Conclusion: One-year treatment with prednisone is associated with a high rate of initial success, but a high recurrence rate. Despite frequent disease relapse, long-term renal and patient outcome was good.