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Updated: Dec 6, 2025
In Vivo, Percutaneous, Needle Based, Optical Coherence Tomography of Renal Masses
Published on: March 30, 2015
Small Renal Masses With Tumor Size 0 to 2 cm: A SEER-Based Study and Validation of NCCN Guidelines
Angela Pecoraro1,2, Giuseppe Rosiello1,3, Stefano Luzzago1,4
11Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Center, Montreal, Quebec, Canada.
Background:
The NCCN Clinical Practice Guidelines in Oncology for Kidney Cancer recommend active surveillance as an option for initial management of T1a 0- to 2-cm renal lesions, in addition to partial nephrectomy, radical nephrectomy, and focal ablation. However, contemporary data regarding the distribution of patient and renal cell carcinoma characteristics within this special patient group are scarce.
Methods:
Within the SEER database (2002-2016), 13,364 patients with T1aNanyMany 0- to 2-cm renal lesions treated with nephrectomy were identified. Data were tabulated according to histologic subtype, Fuhrman grade (FG1-2 vs FG3-4), age category, and sex. In addition, rates of synchronous metastases were quantified.
Results:
Overall, clear-cell (69.3%), papillary (21.4%), chromophobe (6.9%), multilocular cystic (2.0%), sarcomatoid dedifferentiation (0.2%), and collecting-duct histologic subtypes (0.2%) were identified. Advanced age was associated with a lower rate of FG1-2 clear cell histologic subtype (70.8%-50.3%) but higher rates of FG1-2 papillary (11.1%-23.9%) and chromophobe histologic subtypes (6.2%-8.5%). Overall, 14.5% individuals harbored FG3-4 clear cell (9.8%) or FG3-4 papillary histologic subtypes (4.8%), and both were more prevalent in men. FG3-4 clear-cell and FG3-4 papillary histologic subtypes increased with age, more so in women than in men. The overall rate of synchronous metastases was 0.4% and ranged from 0 in the multilocular cystic subtype to 0.9% in the FG3-4 papillary histologic subtype, respectively, except for 13.8% in the sarcomatoid dedifferentiation histologic subtype.
Conclusions:
Most T1a 0- to 2-cm renal cell carcinoma represents the low-grade clear-cell or low-grade papillary histologic subtype, with an FG3-4 minority. Even in patients with the FG3-4 histologic subtype, rates of synchronous metastases are virtually zero.
Insights
Most small kidney cancers (T1a, 0-2 cm) are low-grade clear-cell or papillary subtypes. Even high-grade tumors rarely have metastases, supporting active surveillance for these renal lesions.
Area of Science:
- Oncology
- Urology
- Nephrology
Background:
- National Comprehensive Cancer Network (NCCN) guidelines suggest active surveillance for T1a renal lesions (0-2 cm).
- Data on patient and tumor characteristics for this specific group are limited.
- Understanding these characteristics is crucial for guiding treatment decisions.
Purpose of the Study:
- To analyze patient and renal cell carcinoma characteristics in T1a (0-2 cm) renal lesions.
- To determine the distribution of histologic subtypes and Fuhrman grades (FG).
- To quantify the rates of synchronous metastases in this cohort.
Main Methods:
- Utilized the SEER database from 2002-2016.
- Identified 13,364 patients with T1a (0-2 cm) renal lesions treated with nephrectomy.
- Tabulated data by histologic subtype, Fuhrman grade, age, and sex; quantified metastasis rates.
Main Results:
- Clear-cell (69.3%) and papillary (21.4%) were the most common subtypes.
- FG3-4 subtypes constituted 14.5% of cases, more prevalent in men and increasing with age.
- Synchronous metastases were rare (0.4%), with higher rates in sarcomatoid dedifferentiation (13.8%) and FG3-4 papillary (0.9%) subtypes.
Conclusions:
- T1a (0-2 cm) renal cell carcinoma predominantly comprises low-grade clear-cell or papillary subtypes.
- A minority of these tumors are high-grade (FG3-4).
- Synchronous metastases are exceedingly rare, even in high-grade tumors, supporting conservative management options.
