The natural history of incidentally detected small renal masses

Abstract

BACKGROUND The incidence of renal cell carcinoma (RCC) is increasing, largely due to the widespread use of cross‐sectional imaging. Most renal tumors are detected incidentally as small, asymptomatic masses. To study their natural history, the authors prospectively followed a series of patients with this type of lesion who were unsuited for or refused surgery. METHODS Twenty‐nine patients with 32 masses that measured < 4 cm in greatest dimension (25 solid masses and 7 complex cystic masses) were studied. The primary outcome was tumor size, which was calculated as volume over time. All patients were followed with serial abdominal imaging, and each mass had at least three follow‐up measurements. The median follow‐up was 27.9 months (range, 5.3–143.0 months). RESULTS Overall, the average growth rate did not differ statistically from zero growth (P = 0.09; 95% confidence interval, − 0.005–0.2 cm per year) and was not associated with either initial size (P = 0.28) or mass type (P = 0.41). Seven masses (22%) reached 4 cm in greatest dimension after 12–85 months of follow‐up. Eight masses (25%) doubled their volumes within 12 months. Overall, 11 masses (34%) fulfilled 1 of these 2 criteria of rapid growth. Nine tumors were removed surgically after an average of 3.1 years of follow‐up because it was believed that they were growing fast. No patient had disease progression. CONCLUSIONS Approximately one‐third of small renal masses that are presumed RCCs grow if they are managed conservatively and are followed with serial imaging. The growth rate is slow or undetectable in the majority of patients. These observations raise the possibility of a period of initial observation in selected patients, particularly the elderly or infirm. Cancer 2004;100:738–45. © 2004 American Cancer Society.

Five‐year survival after surgical treatment for kidney cancer

“…With respect to this treatment paradigm, an important underlying assumption, one not supported by several case series, [17][18][19][20][21][22] is that all small renal masses have the universal capacity to grow and metastasize. This assumption, however, has several possible flaws.…”

CUA guideline on the management of cystic renal lesions

“…With the increased use of abdominal imaging, there is a growing number of individuals being diagnosed with renal cystic disease. 1 It is estimated that up to one-third of individuals over 60 years of age will be diagnosed with at least one simple renal cyst following abdominal imaging. 2 Therefore, patients are often referred to urologists for opinions about diagnosis and management of these lesions.…”

Parcial Nephrectomies - results of 12 years from an Oncology Institution

“…Concomitantly there has been a shift towards the detection of small tumors in asymptomatic patients and ultimately in lower stages. 3,4 Although there is some controversy on the true values of mortality rate of RCC, it seems that mortality rates are decreasing. 5,6 Currently the cornerstone treatment of T1a tumors is partial nephrectomy (PN), and this is supported in the European Association of Urology Guidelines on Renal Cell Carcinoma albeit nephron-sparing surgery is indicated for tumors up to 7 cm diameter, whenever technically feasible.…”