Login to Access Video or Poster Abstract: MP55-18
Sources of Funding: National Institutes of Health (NIH), Grant Number TL1 TR001078.

Introduction

Little prospective data exists evaluating comparative oncologic, renal function, and quality of life outcomes for patients with small renal masses (cT1a, ≤4.0 cm). We sought to elucidate these outcomes in the prospectively-maintained Delayed Intervention and Surveillance for Small Renal Masses (DISSRM) registry.

Methods

Patients were enrolled following a choice of primary intervention or active surveillance (AS). Patients who received intervention were further defined by the type of treatment: partial nephrectomy (PN), radical nephrectomy (RN), or ablation. Cancer-specific and overall survival rates were estimated with the Kaplan-Meier method and compared using the log-rank test. Glomerular filtration rate (GFR) was compared across groups at enrollment, 3, 6, and 12 months, and last available measurement. The Short Form 12 (SF-12) questionnaire was administered at enrollment, 6 and 12 months, and every year thereafter. The Physical Component Summary (PCS) and Mental Component Summary (MCS) of the SF-12 were evaluated among groups and over time using ANOVA and linear regression mixed modeling.

Results

Of the 615 enrolled patients, 317 originally chose AS. A total of 256 patients underwent PN, 47 RN, and 36 ablation. PN patients were younger (P < 0.001) and had fewer comorbidities (P < 0.001) than AS patients. Cancer-specific survival at 7 years did not differ among groups (P = 0.5), but overall survival was lower in the AS group (65.9%, P = 0.01) compared to PN (91.9%), RN (89.6%), and ablation (82.9%). From 193 patients, median GFR at enrollment was similar at 71.3, 68.1, 55.5, and 69.5 mL/min/1.73 m² in the PN, RN, ablation, and AS groups, respectively (P = 0.7); at a median follow-up time of 1.5 years, the median GFR was 69.3, 43.7, 55.7, and 68.0 mL/min/1.73 m² across the respective groups (P = 0.2). From a total of 1,932 SF-12 questionnaires, PN patients reported significantly higher PCS scores compared to AS patients at enrollment and annually thereafter until year 5. Patients in AS demonstrated lower PCS scores over time (P = 0.01), but MCS was not meaningfully different among groups or across time.

Conclusions

Superior overall survival and PCS outcomes in PN patients compared to AS patients are attributable to more favorable health characteristics at baseline. However, kidney function at enrollment was not a factor in determining management and does not vary appreciably after intervention type.

Funding

National Institutes of Health (NIH), Grant Number TL1 TR001078.