EURURO Vol. 72 No. 2

E43 320

Letter to the Editor
Re: Archie Fernando, James Pattison,
Catherine Horsfield, David D’Cruz, Gary Cook,
Tim O’Brien. [18F]-Fluorodeoxyglucose Positron
Emission Tomography in the Diagnosis, Treatment
Stratification, and Monitoring of Patients with
Retroperitoneal Fibrosis: A Prospective Clinical Study.
Eur Urol 2017;71:926–33
We read with great interest the article by Fernando et al ,
who suggest a promising role for [18F]-fluorodeoxyglucose
positron emission tomography (FDG-PET) in discriminating
malignancy, deciding on treatment, and surveillance of
patients with retroperitoneal fibrosis (RPF). The authors
found that the avidity of FDG-PET seems to be associated
with patient response to steroids, which could guide more
personalized treatment. We would like to point out several
concerns.
In the past few years, small case series have suggested
that immunosuppressive agents may be effective treat-
ments for patients with RPF. Thus, management of this
disease has shifted from principally a surgical approach to
therapy aimed at regulating the immune system. How-
ever, no immunosuppressive treatment protocol has been
universally accepted owing to lack of persuasive studies.
For medical treatment of RPF, most studies use steroid
monotherapy or combined therapy with other immuno-
suppressants. In the study by Fernando et al , the
authors mentioned that the starting steroid dose was
20 mg twice daily, but they did not described the tapering
and maintenance protocols for steroids in detail, and did
not indicate the follow-up regimens. More importantly,
the poor response rate in their cohort was high: 75.5%
(37/49) of patients failed to respond to steroids. Despite
differences in treatment response criteria, the response
rate is clearly lower than that in all previous studies
. van Bommel et al and Vaglio et al reported that
prednisone can effectively induce remission in patients
with idiopathic RPF, with remission achieved in 22/24
patients on prednisone for 1 yr and in 36/40 patients on
prednisone for 1 mo, respectively. Scheel et al
described the outcomes for 28 patients with RPF who
received combination therapy of prednisone and myco-
phenolate mofetil. Their results indicate that systemic
symptoms were resolved and laboratory abnormalities
were normalized in all patients. Moreover, 25 patients
experienced a reduction in periaortic mass of at least 25%,
as detected by computed tomography. It is unclear
whether an improper treatment strategy or outcome
evaluation method lead to such a low response rate in the
study by Fernando et al , including possible issues such
as a fast tapering regimen, a lacking of maintenance
steroids, or early assessment of treatment response. The
study would have more implications, especially with
regard to steroid therapy, for readers if the authors could
describe their treatment strategy in detail. Furthermore,
the authors should separately analyze previously untreat-
ed patients and pretreated patients because of differences
in baseline characteristics. Analyses that include all of
these patients could involve potential for huge confound-
ing factors.
In summary, the aforementioned results should be
interpreted with caution. We believe that consideration
of our comments by Fernando et al could lead to further
substantiation and elaboration of their valuable results.
Conflicts of interest: The authors have nothing to disclose.
References
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DOI of original article: .
0302-2838/# 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.