Purpose

The proportion of renal cell carcinoma cases diagnosed at stage I is known to be increasing significantly. We characterized stage I tumors further in terms of tumor size at diagnosis using a large national cancer registry.

Materials and methods

The National Cancer Data Base captures approximately 75% of all newly diagnosed cancer cases in the United States. The database was queried for all adults who were diagnosed between 1993 and 2004 with stage I renal cell carcinoma. Trends were assessed in mean size with time as well as in the proportion of stage I tumors diagnosed at less than 2.0, less than 2.5 and less than 3.0 cm.

Results

There were 104,150 patients in the National Cancer Data Base diagnosed with stage I renal cell carcinoma during the study period. A total of 10,279 stage I tumors (9.9%) were less than 2.0 cm, 26,621 (25.6%) were 2.5 cm or less and 39,879 (38.3%) were 3.0 cm or less. Analysis of stage I renal cell carcinoma diagnoses with time demonstrated a statistically significant increase in the proportion of renal masses 3.0 cm or less between 1993 and 2004 (32.5% vs 43.4%). Of tumors 3.0 cm or less the proportion smaller than 2.0 cm increased significantly during the study period from 24.1% in 1993 to 29.4% in 2004. Mean tumor size decreased from 4.1 to 3.6 cm between 1993 and 2004 (p <0.001).

Conclusions

Tumor size at diagnosis is decreasing with time in patients with stage I renal cell carcinoma. These data likely underestimate the proportion of all enhancing renal masses diagnosed at a small size. Patients with small masses may be appropriate candidates for nephron sparing surgery, energy based ablative therapy or active surveillance. Better technologies are needed to determine the diagnosis and prognosis of small enhancing renal masses.

Background

Evidence exists to suggest a pattern of increasing early diagnosis of renal cell carcinoma (RCC). The aim of the study was to analyze patterns of disease presentation and outcome of RCC by AJCC stage using data from the National Cancer Data Base (NCDB) over a 12-year period.

Methods

The NCDB was queried for adults diagnosed between 1993 and 2004 presenting with ICD-O-2 of 3 renal cell tumors arising in the kidney. Cases were classified by demographics, 2002 AJCC stage (6th edition), and histology. The Cochran-Armitage Test for Trend was used to determine statistical significance of trends over time. Cox regression multivariate analysis was used to evaluate the impact of stage and histology on relative survival. SPSS 14.0 was used for analyses.

Results

Between 1993 and 2004 a total of 205,963 patients from the NCDB fit our case definition of RCC. Comparisons between 1993 and 2004 data show an increase in stage I disease and decrease in stage II, III, and IV disease (P < or = .001). The size of stage I tumors also decreased from a mean of 4.1 cm in 1993 to 3.6 cm in 2003. In multivariate analysis, stage, but not histology, predicted relative survival. A 3.3% increase in survival was found for patients diagnosed in 1998 compared with patients diagnosed in 1993.

Conclusions

A greater proportion of newly diagnosed patients with RCC currently present with stage I disease compared with earlier years. Stage predicts relative survival for patients with kidney cancer. More recently diagnosed patients have improved relative survival.

Purpose

Renal cell carcinoma is increasingly diagnosed at stage I, and among stage I cases mean tumor size has been decreasing. Previous reports suggest that nephron sparing surgery is underused for small renal cell carcinomas. We determined updated, population based treatment trends for stage I renal cell carcinoma.

Materials and methods

The National Cancer Data Base, which captures approximately 70% of all cancer diagnoses in the United States, was queried for renal cell carcinoma in adults diagnosed between 1993 and 2007. Trends in treatment, including no surgery, total nephrectomy, partial nephrectomy and focal ablation, were analyzed among all stage I tumors and small stage I tumors categorized by size. Logistic regression was used to identify predictors of nephron sparing surgery (partial nephrectomy or focal ablation).

Results

During the study period we identified 242,740 renal cell carcinomas, of which 127,691 were stage I. For all stage I tumors partial nephrectomy increased from 6.3% to 32.2% of cases and ablation increased from 1.0% to 6.8%. For tumors less than 2.0, 2.0 to 2.9 and 3.0 to 3.9 cm partial nephrectomy increased from 15.3% to 61.1%, 11.0% to 44.2% and 7.2% to 31.1%, respectively (each p<0.001). Female gender, black race, Hispanic ethnicity, lower income, older age and treatment at community hospitals were associated with lower use of nephron sparing.

Conclusions

While total nephrectomy is still likely overused for small renal cell carcinoma, nephron sparing surgery for stage I renal cell carcinoma has increased substantially in the last 15 years with about 4-fold increases across tumor sizes. These trends appear to be ongoing but sociodemographic disparities exist which must be rectified.