Best of AUA 2014: Kidney Cancer

July 10, 2014

Monish Aron, MD, presents the take home messages on kidney cancer from the AUA annual meeting in Orlando, FL.

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• A comparison of active surveillance and primary surgical intervention in patients with small renal tumors found no difference in overall or disease-specific survival over a 4-year follow-up. No patient progressed to metastatic disease, indicating that active surveillance is a viable option for T1a tumors.

• Several abstracts suggested that microRNAs may have a role as prognostic markers in renal cell carcinoma (RCC) and may open the door for novel targeted therapies. A microRNA expression profile has been used to potentially differentiate benign tumors from cancer on needle biopsy and may also differentiate among RCC subtypes.

• A dendritic cell-based vaccine was highly effective in eradicating both primary and metastatic cells in a mouse model of metastatic RCC, proving more effective than sunitinib (Sutent) monotherapy.

• Contrary to popular belief, kidney cancer mortality is decreasing as a result of early diagnosis and treatment, a population-based dataset found. Over 30 years, kidney cancer mortality has declined from 4.3 per 100,000 to 3.5 per 100,000.

• Lifestyle modification can help reduce mortality from kidney cancer. Physical activity leads to a 50% reduction in cancer-specific mortality, while obesity leads to a threefold increase in kidney cancer deaths and smoking leads to a twofold increase in kidney cancer deaths.

• Magnetic resonance spectroscopy was able to reliably differentiate between benign and malignant lesions in the kidney, suggesting this technology could potentially allow for better diagnosis of benign versus malignant tumors and thereby potentially decrease overtreatment of small renal masses.

• There is a difference in the DNA methylation signature between benign and malignant kidney biopsies, potentially paving the way for a panel of DNA methylation markers that may improve the reproducibility and predictability of renal mass biopsies for preoperative planning.

• Renal mass biopsies accurately predicted histology in only 72% of patients and accurately predicted grade in only 24%. The biopsy complication rate was 22%, with 6% being high grade.

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• In a more mature dataset, renal tumor biopsies could provide a diagnosis in up to 89% of patients and surgery could be avoided in 23% based on a negative preoperative biopsy. Final agreement between biopsy and histopathology could be achieved in 92% of patients, and from 2001 to 2013, the non-diagnostic rate dropped from 15% to 6%, signifying a learning curve in performing and interpreting biopsy correctly.

• Active surveillance may be reasonable even for patients with T1b tumors. Tumors >4 cm in diameter grow at about 0.44 cm per year, about the same as smaller tumors. Fifteen percent showed no growth, and 34% progressed to intervention.

• Partial nephrectomy decreased the incidence of cardiovascular events by 50% versus radical nephrectomy. But 10-year other-cause mortality rates were the same for partial and radical nephrectomy, and partial nephrectomy did not confer a survival advantage.

• In partial nephrectomy, tumor enucleation is a reasonable technique to treat small renal masses that maximizes preservation of normal-functioning parenchyma. Ischemia time for enucleation was 4 minutes shorter and OR time 32 minutes shorter than that for sharp tumor excision.

• A study showing a 5% positive surgical margin rate after partial nephrectomy showed no difference in progression-free survival between patients who had positive versus negative margins.

• Contrary to a common belief, patients who have compromised kidneys prior to undergoing partial nephrectomy and those who have healthy kidneys have the same rate of kidney function recovery after ischemic insult.

• Patients who have surgically induced chronic kidney disease have a slower rate of kidney function decline and superior other-cause mortality than patients who have medical or medical/surgical chronic kidney disease.

• In patients with locally advanced T2 and T3 tumors, axitinib (Inlyta) was able to reduce tumor size by about 28%, with 46% of patients showing a response and 54% showing stable disease.

• In patients with inferior vena cava (IVC) thrombus treated with targeted therapies, mean tumor size decreased in 74% of patients. Mean reduction was about 14 mm, and the level of the thrombus was changed in 16%, indicating that the benefit of targeted therapy is limited.

• In patients with IVC thrombus and metastatic RCC, adding surgery to targeted therapy did not confer any benefit in progression-free or overall survival compared with targeted therapy alone.

• Those patients with metastatic RCC who are on statins tend to have superior cancer-specific survival compared with those who are not on statins, and on multivariate analysis, statins independently predicted cancer-specific survival.UT

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