WATCHFUL WAITING APPROPRIATE FOR SOME RENAL TUMORS  

Surveillance may be a feasible option for patients with small renal masses who are not acceptable candidates for surgery. According to the findings of a new study, surveillance with imaging, such as MRI, ultrasound, and CT scan, does not appear to adversely affect renal cancer-specific survival.

"Surveillance is a reasonable option for patients with small kidney tumors, particularly those who are older or have considerable co-morbid conditions," said lead author William C. Huang, MD, assistant professor of urologic oncology at New York University Medical Center in New York. "Surveillance of small kidney tumors did not increase the risk of dying of kidney cancer, and surgical treatment — particularly radical nephrectomy — was associated with cardiovascular complications and poorer survival over time."

Dr. Huang presented highlights of his study during a presscast held in advance of the 4th Annual Genitourinary Cancers Symposium, being held February 14 through 16, 2013, in Orlando, Florida.

The incidence of renal cancer is on the rise, but that is believed to be due to an increase in imaging for unrelated conditions, Dr. Huang explained. Thus, even though there is no routine screening for renal tumors, most newly diagnosed kidney cancers are now found at a very small size, roughly less than 2 inches.

"We also know that kidney cancers at this size represent a heterogeneous group of tumors, and therefore not all of these tumors are necessarily dangerous," he said.

But nevertheless, for years surgery has been the standard treatment for these tumors and usually involves removal of the entire kidney. But emerging evidence now shows that surgical intervention in an older or morbidly ill patient may be unnecessary and can have an adverse affect on nononcologic outcomes, Dr. Huang added.

No Differences in Cancer Specific Survival

Dr. Huang and colleagues conducted a nonrandomized retrospective cohort study to identify predictors of surveillance and analyze the impact of surveillance on overall survival, kidney cancer-specific survival, and cardiovascular (CV) events, as compared with surgical intervention.

Using the Surveillance, Epidemiology, and End Results (SEER) cancer registry data that is linked with Medicare claims, the authors identified patients who were aged 66 years or older and who had received surgery or surveillance for small lesions (< 4 cm). Surveillance was defined by the absence of a claim for surgery within the first 6 months following diagnosis.

Of the 8317 patients who were diagnosed between 2000 and 2007, 7148 had a pathologic diagnosis. Within this group, 78% had surgery while 22% had surveillance. The use of surveillance varied from 25% to 37%. Dr. Huang pointed out that the use of surveillance had slowly increased over the study period.

At a median follow-up of 59 months, only 3% of patients died of kidney cancer, and cancer-specific survival did not vary by the type of treatment the patient received (hazard ratio [HR] 0.66; confidence interval [CI] 0.42 - 1.02; P = not significant).

However, about a quarter of patients (24%) had at least 1 CV event and 21% of patients died, Dr. Huang explained.

Surveillance was associated with a significant lower risk for a CV event (HR 0.51; CI 0.44 - 0.60; P < .00001), and surveillance over time was associated with significant lower risk for death from any cause; 6 months: HR 1.27; 7 - 36 months: HR 0.70; > 36 months: HR 0.37.

"Surveillance over time was associated with a significantly lower risk of death from any cause, and this was apparent over time," Dr. Huang said. "From 7 months on, this was statistically significant."

He added that while this is a reasonable strategy for patients with small kidney tumors who are older or have considerable comorbid conditions, a number of small tumors can become lethal over time. "Therefore, surgery remains the treatment of choice for patients with a normal life expectancy," Dr. Huang concluded.

As the majority of renal lesions are found incidentally, via nonkidney imaging, questions arise when the patient is referred, Bruce J. Roth, MD, who moderated the presscast, commented.

"There is some question of how to approach this," said Dr. Roth, a professor of medicine at Washington University School of Medicine, St. Louis, Missouri. "Certainly if there was a very aggressive cancer you would want to take it out when it is small, but by the same token, lesions of this size can be non malignant or very indolent with very slow growth patterns. We would prefer not to do surgery on patients who are unlikely to benefit from it."

This study is important because it shows that there is not a negative impact by watching these lesions, but also that surgery can have negative impact on CV mortality, he noted. "So I think this will help patients realize that a watchful waiting approach is a reasonable option medically," Dr. Roth said.

The authors have disclosed no relevant financial relationships.

4th annual Genitourinary Cancers Symposium. Presented February 16, 2013. Abstract 343.