ATLANTA—Delayed intervention for treating small renal masses may be appropriate for selected patients, especially those with competing comorbidities, a study found. This conservative approach has little adverse effect on pathological and clinical outcomes, researchers note.


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Over the past two decades, the incidence of renal cell carcinoma (RCC) has increased by approximately 3% annually, with as many as two thirds of cases picked up incidentally through imaging studies, said investigator Raj Pruthi, MD, associate professor of surgery/urology and director of urologic oncology at the University of North Carolina at Chapel Hill. There is a growing concern about the best management of these incidental tumors, which are typically less than 4 cm in diameter. The researchers evaluated outcomes of those initially managed expectantly and who subsequently underwent intervention to characterize those who require subsequent therapy versus continued observation.


The team analyzed data on 43 patients with 46 renal masses who underwent initial planned expectant management of solid, enhancing renal tumors. The researchers characterized the clinical findings among those requiring intervention and they also evaluated the type of intervention and the impact of delaying therapy in terms of clinical and pathological outcomes.


“This is one of the largest expectant management series, but it still represents a relatively small cohort size,” said Dr. Pruthi, who reported the findings here at the American Urological Association annual meeting. “There have been a handful of other series, and all seem to suggest that observation may be a reasonable approach for certain patients, especially those with significant medical comorbidities. Our follow-up of three years is relatively long for such case series, and this study uniquely evaluates the impact of delay in intervention in a subgroup of patients who underwent surgery after an initial period of observation.


“Interestingly,” he continued, “we also observed in our entire cohort that younger patients had more rapidly growing tumors than older patients, and that tumor size did not significantly predict growth rate.”


In fact, 11 of the 46 masses (24%) were greater than 4 cm in diameter and their median growth rates (0.35 cm/yr) were not different than patients with tumors less than 2 cm (0.35 cm/yr), he said.


Fifteen patients required intervention at a mean interval of 13 months. Eight cases required laparoscopic partial nephrectomy, two required open partial nephrectomy, and four required laparoscopic radical nephrectomy. These 15 patients had a mean age of 56.2 years and had an initial tumor mass of 2.6 cm in diameter. Among these, the mean tumor growth was 0.90 cm per year and the median growth was 0.77 cm per year. Only 31% of these patients had significant medical comorbidities.


The patients who did not require intervention were older, with a mean age of 71.5 years, and the initial mass size was 3.1 cm. The mean annual growth rate was 0.61 cm per year and the median growth rate per year was only 0.27 cm, suggesting that over half of these patients had tumors that grew at less than 0.3 cm per year. Eighty percent of these patients had other significant medical problems.


Among the 14 patients undergoing subsequent intervention, 12 (86%) had RCC, and all of these tumors were pT1, and 10 out of the 12 had a tumor grade of 2 or less. All the patients were followed for a mean of 40 months. One patient who had a subsequent intervention died of other causes 30 months after surgery. No patient had upstaging of disease secondary to delay. In addition, on retrospective re-evaluation, no patient who ultimately underwent radical nephrectomy would have been a candidate for a nephron-sparing approach, even if intervention took place earlier.


“Renal masses may be managed conservatively, especially in the appropriately selected patients, such as those with significant medical comorbidities,” Dr. Pruthi said. “Although we always want things to be black and white in deciding who to treat and who to observe, this decision-making remains a gray area.”