EURURO Vol. 71 No. 4

559 692

the lines of a nomogram predicting the risk of overall
recurrence after RC for example, it would be worth
aiming for this moonshot of meticulously assessing
distinctive predictors of SUT and pooling them into a novel
nomogram or similar multivariate risk calculator. Specifi-
cally for rare potential scenarios, such as the development
of SUT, shared-decision making based on statistically
grounded evidence is mandatory and crucial to guide
management strategies
On the question of how to treat patients harboring SUT,
we are confronted with a dilemma of sorts. Considering
studies that provide detailed information on recurrence
location, 88% of 238 patients and 67% of 51 patients were
diagnosed with solitary upper tract SUT and urethral SUT
without distant metastases, respectively. This is interesting,
as it implies that within this subset of the literature, the
majority of recurrences indeed present as SUT without
further tumor spread. Considering a different set of studies
that describe explicit treatment strategies, the latter are
quite diverse. Of note, in both upper tract and urethral SUT,
approximately two-thirds of cases underwent radical
nephroureterectomy or urethrectomy, while a minority of
patients were offered systemic chemotherapy, endoscopic
treatment, or immunotherapy and bacillus Calmette-
Gue´ rin instillation. A major drawback here is that patients
were heterogeneous regarding tumor stage and grade, some
had distant metastases, and for some the tumor character-
istics were unknown. Thus, it may not be bold to conclude
that we are still vague about what to do best in the case of
solitary SUT, as there are no data available on comparative
effectiveness in this particular setting.
Given the often-cited clonality theory of multiple
urothelial tumors, we can approach this issue from two
different vantage points. According to the field canceriza-
tion theory , SUTs may be treated like primary upper tract
or urethral carcinomas, as it is hypothesized that SUTs are
metachronous nonrelated tumors at a different site. In this
case, it may be valid to rely on existing stage-specific
guideline recommendations for primary upper tract or
urethral carcinoma . Conversely, according to the most
recently updated guidelines, upper tract carcinoma in
patients with previous RC for urothelial cancer of the
bladder is considered high risk by definition, regardless of
tumor stage or grade, for which the monoclonality theory
may apply, according to which multiple metachronous
urothelial tumors are derived from a single genetically
transformed cell . In upper tract SUT, for example, this
would lead to more stringent recommendations towards
radical nephroureterectomy, except for patients with distal
ureteral tumors, for whom distal ureterectomy may be
considered as a secondary treatment option . Overall, we
believe that advanced risk assessment tools may improve
clinical algorithms on how to follow patients after RC at a
given risk of SUT, which might eventually increase early
detection. For those who ultimately suffer from solitary
SUT, treatment decisions should be made individually, but
radical approaches may confer benefits and should be
offered whenever possible.
Conflicts of interest: The authors have nothing to disclose.
References
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