Over the last decade, nephron-sparing surgery (NSS) has emerged as a safe and effective alternative to radical nephrectomy for the treatment of small renal tumors, with documented benefits for renal function and health-related quality of life. Nevertheless, it is unclear to what extent NSS has been adopted as standard clinical practice, or how the growing popularity of laparoscopic radical nephrectomy has affected its use.OBJECTIVE
To define current US practice patterns for the surgical treatment of small renal masses.DESIGN AND INTERVENTION
Patients with localized or regional kidney cancer were identified from the US Surveillance, Epidemiology and End Results (SEER) registry for 1988-2001. Those with a primary tumor ≤7 cm in size, who underwent surgery as their first-line treatment, were included. Demographic and clinical information were obtained for each patient, including race, age, gender, marital status, year of diagnosis, SEER site, and tumor laterality, grade, and histology. Tumor size was categorized as <2 cm, 2-4 cm, or >4-7 cm. The proportion of patients treated with NSS (including local excision, wedge or segmental resection, and cryosurgery, laser therapy, and thermal ablation) versus radical nephrectomy (with or without lymph-node dissection) was calculated.OUTCOME MEASURES
Independent associations between patient and tumor characteristics and the use of NSS were investigated. The impact of patient-specific and cancer-specific factors on all-cause mortality was also examined.RESULTS
Of 14,647 eligible patients, 1,401 (9.6%) were treated with NSS. The remaining 13,246 (90.4%) underwent radical nephrectomy. The use of NSS increased over the study years, from 4.6% of patients in 1988-1989, to 17.6% of patients in 2000-2001 (P<0.001). A similar increase was observed in tumors <2 cm in size (from 14% to 42%, P<0.001) and tumors 2-4 cm in size (from 5% to 20%, P<0.001), but the proportion of tumors >4-7 cm in size treated with NSS remained ≤6% over the study period. Factors independently associated with the use of NSS were a younger patient age, smaller tumor size, and a more recent year of diagnosis (all P<0.05). Tumors <2 cm and 2-4 cm in size were 9.6 times and 3.8 times, respectively, more likely to be treated with NSS than were tumors >4-7 cm in size. The use of NSS rather than radical nephrectomy did not affect all-cause mortality (hazard ratio 0.9, 95% 0.8-1.1).CONCLUSION
The use of NSS for small renal masses increased between 1988 and 2001, but remained relatively low. Given the documented benefits of renal preservation, these findings could indicate a quality-of-care concern that warrants further investigation.