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Page 12 of 19 Deivasigamani et al. Mini-invasive Surg 2023;7:9 https://dx.doi.org/10.20517/2574-1225.2022.99

Oncological outcomes - assessment
Analysis of oncologic outcomes comparing nephron-sparing techniques is limited in reliability and utility
due to biases in patient and tumor selection, disparities in success criteria, differences in follow-up
timeframes, and variability in malignancy rates since many studies report outcomes that are not limited to
patients with positive tissue diagnosis. Additionally, although many studies discuss the local tumor
recurrence rate, patients who undergo CA for treatment of SRM often undergo repeat treatment with CA,
so the local tumor recurrence rate is likely of less clinical relevance than metastasis-free survival and cancer-
specific survival. Similarly, in a long-term follow-up study of patients who underwent PCA, the majority of
patients who did have local tumor recurrence after initial technical success underwent repeat PCA .
[72]

CA AND ITS IMPLICATIONS ON T1B RENAL MASSES
As discussed in complications and oncologic outcomes, both the rate of complications and the rate of
recurrence are higher with increased maximum tumor diameter [51,58,69,70] . This explains why the guidelines
from the AUA, NCCN, and EUA do not currently recommend the use of ablation techniques for the
treatment of renal cancer for cT1b renal masses [16,17] . The SIR guidelines do discuss the consideration of CA
for the treatment of cT1b tumors, but they also suggest the need for continued investigation and improved
[19]
evidence to make stronger recommendations regarding the use of ablation techniques for cT1b tumors .
There have been several studies reporting outcomes on patients with cT1b renal tumors treated with CA,
but no randomized trials have been performed to compare CA to PN or other ablative techniques, so any
comparisons made with retrospective studies that attempt to control for patient factors and tumor factors
will have limited reliability and utility. Nonetheless, in a recent systematic review of reports on ablation
techniques for the treatment of cT1b renal tumors treated with CA, the reported outcomes show that CA
appears to be a safe and effective treatment strategy . Further long-term and higher-quality evidence will
[83]
be necessary to truly assess the efficacy of CA in treatment of larger renal masses, but this appears to be a
reasonable treatment strategy for select patients with cT1b renal tumors in the hands of experienced
providers. Table 2 shows the comprehensive review of CA and its implications on T1b renal masses.

POST-TREATMENT MONITORING
Post-procedure follow-up imaging is used for assessment of technical success following ablation procedures
since there is no surgical margin for pathology to assess for complete treatment of the tumor margins.
When there is residual tumor evident at initial follow-up imaging 1-3 months following CA, this is
considered a “Residual Unablated Tumor” , and the rate of patients with residual unablated tumor is used
[66]
to assess the “primary technical efficacy” of treatment . When patients have residual unablated tumors,
[83]
they most often undergo another ablation procedure, and the rate of patients with residual unablated
tumors after including those who underwent a second ablation procedure is used to assess “secondary
technical efficacy” . The terms “local tumor progression” and “local tumor recurrence” are used when there
[83]
is a tumor focus on the margin of the ablation zone after initial follow-up imaging shows the technical
success of complete tumor ablation [68,83] . Reports on patients who underwent ablative procedures must be
interpreted with caution when cancer-specific outcomes including the rate of technical efficacy and rate of
local tumor recurrence are discussed because accurate analysis of cancer-specific outcomes requires that
patients have undergone a biopsy to prove they had malignancy, but many reports will include all patients
treated instead of limiting to patients with positive biopsy .
[90]

There appears to be a survival benefit to follow-up surveillance after treatment of renal cancer [91,92] , but there
is not a universally agreed upon follow-up surveillance strategy for patients who underwent treatment for
renal cancer. Post-treatment monitoring should include history and physical, as well as imaging of the
abdomen and chest to assess for recurrence and metastasis, but the interval of follow-up and imaging, as