Steroid Dosing for Retroperitoneal Fibrosis
For idiopathic retroperitoneal fibrosis, initiate prednisone at 1 mg/kg daily (or 0.5-1 mg/kg daily) for 1-2 months, then taper gradually over 6-12 months to a maintenance dose, with total treatment duration of approximately 2 years. 1, 2
Initial Induction Therapy
Start with prednisone 1 mg/kg daily for the first month to achieve disease remission 1. An alternative regimen uses prednisolone 60 mg on alternate days for 2 months, which may reduce steroid-related side effects while maintaining efficacy 2.
- The goal of induction therapy is to achieve clinical remission, defined by symptomatic improvement and normalization of inflammatory markers 3
- Relief of symptoms typically occurs within the first 3 months of treatment 2
- Ureteral obstruction should be managed with nephrostomy tubes or ureteral stents prior to or concurrent with steroid initiation 2
Tapering and Maintenance Phase
After achieving remission at 1 month, reduce prednisone to 0.5 mg/kg daily and continue tapering over the next 8 months 1. The alternate-day regimen tapers from 60 mg to 5 mg daily over 2-4 months 2.
- Maintenance therapy should continue for a total duration of approximately 2 years to prevent relapse 2
- The relapse rate with prednisone monotherapy is approximately 6-17% when treatment is completed appropriately 1
- Patients require periodic monitoring for the rest of their lives, as late recurrences can occur 2
IgG4-Related Disease Considerations
Response to steroid monotherapy appears superior in RF associated with IgG4-related disease compared to idiopathic RF 4.
- RF-IgG4-RD cases show dramatic response to steroids alone, with complete remission achievable in most patients 4
- Idiopathic RF (non-IgG4-related) may benefit from initial combination therapy rather than steroid monotherapy 4
- Consider checking serum IgG4 levels to guide treatment strategy 4
Combination Therapy Options
For steroid-refractory cases or to reduce steroid exposure, consider adding immunosuppressive agents:
- Mycophenolate mofetil 2 g/day plus prednisone 1 mg/kg daily achieves remission in most patients, allowing steroid discontinuation after mean of 7 months and MMF withdrawal after 27 months 5
- Colchicine plus low-dose steroids (<0.5 mg/kg/day) produces similar remission rates to higher steroid doses alone, with potential recurrence prevention benefits 3
- Tamoxifen is less effective than prednisone, with relapse rates of 39% versus 6% at 8 months 1
Monitoring and Response Assessment
Assess treatment response at 3 months using objective parameters:
- Regression of retroperitoneal mass on CT/MRI (expect >50% reduction by 8-12 months) 3
- Normalization of inflammatory markers (CRP, ESR) 5
- Improvement in renal function (serum creatinine) 5
- Relief of symptoms and removal of ureteral stents when feasible 5
Common Pitfalls to Avoid
Do not taper steroids too rapidly - the 26-month cumulative relapse probability is 17% with appropriate tapering versus 50% with inadequate treatment 1.
Do not use tamoxifen as first-line monotherapy - it is significantly inferior to prednisone for preventing relapses 1.
Do not assume all RF responds equally to steroids - non-IgG4-related cases may require combination therapy from the outset 4.
Steroid-Related Adverse Effects
Monitor for Cushingoid features, hypercholesterolemia, impaired glucose tolerance, and urinary tract infections (particularly in patients with ureteral stents) 1, 5. The alternate-day regimen may reduce some side effects while maintaining efficacy 2.