Most reports of active surveillance (AS) of small renal masses (SRMs) lack biopsy confirmation, and therefore include benign tumors and different subtypes of renal cell carcinoma (RCC).
We compared the growth rates and progression of different histologic subtypes of RCC SRMs (SRMRCC) in the largest cohort of patients with biopsy-characterized SRMs on AS.
Data from patients in a multicenter Canadian trial and a Princess Margaret cohort were combined to include 136 biopsy-proven SRMRCC lesions managed by AS, with treatment deferred until progression or patient/surgeon decision.
Growth curves were estimated from serial tumor size measures. Tumor progression was defined by sustained size ≥4 cm or volume doubling within 1 yr.
Median follow-up for patients who remained on AS was 5.8 yr (interquartile range 3.4-7.5 yr). Clear cell RCC SRMs (SRMccRCC) grew faster than papillary type 1 SRMs (0.25 and 0.02 cm/yr on average, respectively, p = 0.0003). Overall, 60 SRMRCC lesions progressed: 49 (82%) by rapid growth (volume doubling), seven (12%) increasing to ≥4 cm, and four (6.7%) by both criteria. Six patients developed metastases, and all were of clear cell RCC histology. Limitations include the use of different imaging modalities and a lack of central imaging review.
Tumor growth varies between histologic subtypes of SRMRCC and among SRMccRCC, which likely reflects individual host and tumor biology. Without validated biomarkers that predict this variation, initial follow-up of histologically characterized SRMs can inform personalized treatment for patients on AS.
Many small kidney cancers are suitable for surveillance and can be monitored over time for change. We demonstrate that different types of kidney cancers grow at different rates and are at different risks of progression. These results may guide better personalized treatment.
European urology. 2020 Jul 14 [Epub ahead of print]
Antonio Finelli, Douglas C Cheung, Ashraf Al-Matar, Andrew J Evans, Christopher G Morash, Stephen E Pautler, D Robert Siemens, Simon Tanguay, Ricardo A Rendon, Martin E Gleave, Darrel E Drachenberg, Joseph L Chin, Neil E Fleshner, Masoom A Haider, John R Kachura, Jenna Sykes, Michael A S Jewett
Division of Urology, Department of Surgery, Princess Margaret Cancer Centre and the University Health Network, University of Toronto, Toronto, ON, Canada. Electronic address: ., Division of Urology, Department of Surgery, Princess Margaret Cancer Centre and the University Health Network, University of Toronto, Toronto, ON, Canada., Department of Pathology, Princess Margaret Cancer Centre and the University Health Network, University of Toronto, Toronto, ON, Canada., Division of Urology, Department of Surgery, University of Ottawa, Ottawa, ON, Canada., Divisions of Urology and Surgical Oncology, Western University, London, ON, Canada., Department of Urology, Queen's University, Kingston, ON, Canada., Division of Urology, Department of Surgery, McGill University Health Centre, Montreal, QC, Canada., Department of Urology, Queen Elizabeth II Health Sciences Centre and Dalhousie University, Halifax, NS, Canada., Department of Urologic Sciences, University of British Columbia, Vancouver, BC, Canada., Department of Surgery, Section of Urology, University of Manitoba, Winnipeg, MB, Canada., Joint Department of Medical Imaging, Sinai Health System, Princess Margaret Cancer Centre and the University Health Network, University of Toronto, Toronto, Ontario, Canada., Department of Biostatistics, Princess Margaret Cancer Centre, Toronto, ON, Canada.
PubMed http://www.ncbi.nlm.nih.gov/pubmed/32680677