Most early stage kidney cancers are renal cell carcinomas (RCCs), and most are diagnosed incidentally by imaging as small renal masses (SRMs). Indirect evidence suggests that most small RCCs grow slowly and rarely metastasize.
To determine the progression and growth rates for newly diagnosed SRMs stratified by needle core biopsy pathology.
Design, setting, and participants
A multicenter prospective phase 2 clinical trial of active surveillance of 209 SRMs in 178 elderly and/or infirm patients was conducted from 2004 until 2009 with treatment delayed until progression.
Patients underwent serial imaging and needle core biopsies.
We measured rates of change in tumor diameter (growth measured by imaging) and progression to ≥4
Results and limitations
Local progression occurred in 25 patients (12%), plus 2 progressed with metastases (1.1%). Of the 178 subjects with 209 SRMs, 127 with 151 SRMs had
This is the first SRM active surveillance study to correlate growth with histology prospectively. In the first 2 yr, the rate of local progression to higher stage is low, and metastases are rare. SRMs appear to grow very slowly, even if biopsy proven to be RCC. Many patients with SRMs can therefore be initially managed conservatively with serial imaging, avoiding the morbidity of surgical or ablative treatment.
Keywords: Active surveillance, Kidney cancer, Small renal mass.
a Division of Urology, Departments of Surgery and of Surgical Oncology, Princess Margaret Hospital and the University Health Network, University of Toronto, Canada
b Division of Urology, Department of Surgery, University of Ottawa, Canada
c Division of Urology, St. Joseph's Health Care London, University of Western Ontario, Canada
d Department of Urology, Queen's University, Canada
e Division of Urologic Oncology, Department of Surgery, McGill University Health Centre, Canada
f Department of Urology, Queen Elizabeth II Health Sciences Centre and Dalhousie University, Canada
g Division of Urology, The Prostate Centre, Vancouver General Hospital, Canada
h Department of Surgery, Section of Urology, University of Manitoba, Canada
i Department of Health Informatics, Princess Margaret Hospital, Canada
j Division of Urology, London Health Sciences Centre, University of Western Ontario, Canada
k Department of Pathology, Princess Margaret Hospital and the University Health Network, University of Toronto, Canada
l Ontario Cancer Institute and Princess Margaret Hospital, University of Toronto, Canada
m Department of Medical Imaging, Princess Margaret Hospital and the University Health Network, University of Toronto, Canada
n Department of Biostatistics, Princess Margaret Hospital, Canada
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© 2011 European Association of Urology, Published by Elsevier B.V.