Active surveillance for selected patients with renal masses

Abstract

BACKGROUND. The objective of the current study was to evaluate the outcome of a surveillance strategy in patients with renal masses. METHODS. The medical records of patients with renal masses diagnosed between January 1992 and May 2006 were reviewed retrospectively. In all, 45 patients with renal masses under observation were identified. Of these, 35 patients with 44 renal masses measuring <4 cm in dimension at the time of diagnosis and who were followed for at least 6 months were included in the review. Patients elected observation because of age, comorbidity, solitary kidney, or bilateral renal masses. Medical records were reviewed to determine tumor size and volume changes as well as clinical progression requiring treatment, the development of metastatic disease, or death. RESULTS. A total of 35 patients (21 men and 14 women) with 44 renal masses were observed for a mean follow‐up of 47.6 months. The mean age of these patients was 71.8 years. The majority of the patients (89%) were asymptomatic at the time of diagnosis. The mean and median initial tumor dimension was 2.2 cm and 2.2 cm, respectively (range, 0.5–4 cm). Of the 35 patients, 2 (5.7%) were lost to follow‐up, 8 (22.9%) underwent surgical resection, and 9 (25.7%) died of other causes. The mean dimension growth rate was 0.21 cm/year (range, 0.03–1.9 cm/year). The mean and median volume growth rate was 2.7 cc/year and 1.4 cc/year, respectively. Progression to metastatic disease was identified in 2 patients (5.7%). CONCLUSIONS. The majority of renal masses will grow if observed and some may require treatment. Initial tumor size cannot predict the natural history of renal masses. A small but non‐negligible risk of developing metastatic disease exists in this patient population. Further research should focus on the role of biopsy and on identification of prognostic parameters allowing more accurate prediction of tumor growth and metastasis. Cancer 2007. © 2007 American Cancer Society.

Renal Mass Biopsy to Guide Treatment Decisions for Small Incidental Renal Tumors: A Cost-effectiveness Analysis

“…To address the possibility that contemporary NSS mortality rates could be lower, we varied this estimate substantially to determine the potential effects on our results. We found that below a rate of 1%, the NSS strategy would yield a slightly higher quality-adjusted life expectancy (38)(39)(40)(41)(42)(43)(44)(45)67 ). Furthermore, adequate data were not available to validate our model predictions for patients with biopsynegative RCC using an independent data source.…”

“…However, because practitioners have become more confi dent in renal mass biopsy results, fewer correlative surgical histologic results for biopsy-negative tumors are available ( 9,10,14,26,29,62 ), and the use of tumor indolence as a proxy for surgical confi rmation of benignity has increased. However, clinical follow-up of false-negative results does not prove tumor benignity, and the assumption that tumor indolence and benignity are equivalent may contribute to higher ( 38,41,44 ). † Although growth data were reported, the percentage of tumors that grew during follow-up was not reported; thus, data from this study could not be incorporated for this statistic.…”

“…Lane et al (14) found an overall complication rate of 4.7% (17 of 362), a major complication rate of 0.3% (one of 362), and no surveillance was terminated and tumors were treated with surgery or ablation (38)(39)(40)(41)(42)(43)(44)(45). We therefore conservatively assumed that 29% of tumors that grew at each surveillance point would be treated surgically but varied this assumption widely in sensitivity analysis.…”

“…First, a selection bias could be present, causing tumors followed by surveillance to be more indolent, on average, than those that are immediately surgically resected. Second, the average follow-up surveillance period in the literature was intermediate in length (33 months) (38)(39)(40)(41)(42)(43)(44)(45)67 ). Considering these factors, we calculated the 95% confidence interval surrounding the adjusted value (0.014; 95% confi dence interval: 0.032, 0.004) and used the upper boundary (ie, 0.032) for further calculations, thereby assuming a higher probability of metastasis for biopsy-negative RCC than reported in the literature.…”

“…However, we found that, even if the accuracy of biopsy were to be substantially lower, the resulting effect on life expectancy would be minimal. This is because of the relatively low propensity for patients with small unresected RCC to develop metastases during surveillance (38)(39)(40)(41)(42)(43)(44)(45)67 ). From a life-expectancy perspective, the small risk of incorrectly triaging a biopsy-negative RCC to imaging surveillance potential for false-negative results and the possibility of biopsy track seeding with cancer cells ( 11-13 ).…”