📃 Paper Title: Small renal masses progressing to metastases under active surveillance: a systematic review and pooled analysis
🧍 Author: Smaldone
🕒 Year: 2012
📚 Journal: Cancer
🌎 Country: USA
ㅤContext to the study:
What do you know about the evidence for surveillance of small renal masses? (Smaldone and Jewett could be referenced)
ㅤ✅ Take-home message of study:
This paper is a systematic review and pooled analysis of active surveillance (AS) for small renal masses (SRMs) assessing the incidence of metastases whilst on AS.
• Approximately 2% of patients with SRM under AS were identified with metastases, identified at mean 3-4 years.
• Lesions that metastasised tended to be larger and grow faster than those that did not. No lesions that remained stable in size metastasised (there is one case report in literature of this happening).
• Of a subgroup with data (n=284 masses), almost half (45.4%) ultimately underwent delayed intervention.
• The conclusion is that an initial period of AS may be acceptable for patients with competing health risks, with delayed intervention an option for cases demonstrating significant growth (albeit no threshold identified).
ㅤ Systematic review and pooled analysis
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Study participants:
All clinical series reporting outcomes of surveillance for SRMs
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Key study outcomes:
• Included 18 series overall and 6 for pooled analysis
• Ultimately, 18 of 880 (2.05%) patients (936 masses) had progression with metastases, dx at mean 40.2 months.
• Analysis of these lesions showed their initial size (diametric and volumetric; mean 4.1 ± 2.1 cm diametric), and their growth rate (mean 0.8 ± 0.65 cm/year diametric, mean 27.1 ± 24.9cm3 volumetric) to exceed those of lesions that did not metastasise (mean 0.3 ±
0.4cm/year diametric growth). Patients also tended to be older (mean 75 vs 66 years).
• Overall, on pooled analysed of 284 with individual-level data, at mean 33.5 months, the mean linear growth rate for SRM was 0.13 ±
0.38cm/year and mean volumetric growth rate was 6.3cm3/year • Of masses that demonstrated no interval growth on surveillance (n=65), no cases of metastases were identified.
• Approx. 100 had histology available, 80% of these malignant (predom clear cell) and 88% low grade
• Of a subgroup with data (n=284 masses), 45.4% underwent delayed intervention (for patient preference, lesion growth, improved health etc.)
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Study Limitations:
• Applies to subgroup with competing health risks only
• Presumed heterogeneity of included series between imaging approach, histological sampling, threshold for intervention
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