As the incidence of small renal masses (SRMs) increases, management options are increasing, and different modalities for biopsy and treatment are becoming available.
At the “Diagnosis and Treatment of Local Renal Cancer” general session, held on February 18 at the 2017 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium in Orlando, Florida, the latest advances in managing SRMs, including the role of active surveillance, radiographic biopsy, percutaneous biopsy, and ablation, will be discussed.
Biopsy Strategies
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SRMs are localized, renal tumors smaller than 4 cm that are often found incidentally. Current biopsy strategies for SRMs are limited by a relatively low accuracy, and ASCO guidelines do not recommend a particular technique.1 According to Mohamad E. Allaf, MD, of the Johns Hopkins University School of Medicine in Baltimore, Maryland, the negative predictive value is about 68%, and the non-diagnostic rate is about 15%. Dr Allaf will discuss advanced imaging technology to pinpoint SRM histology at the general session.
“Given this, my group has developed and adapted several nuclear medicine tests to look at both localized and metastatic disease,” Dr Allaf told Cancer Therapy Advisor. In a small study, prostate-specific membrane antigen–targeted 18F-DCFPyL PET/CT accurately identified sites of metastatic renal cell carcinoma.2
“For localized disease, we have been using sestamibi imaging, which measures the mitochondrial content of the tumor, to determine whether the tumor is benign or malignant,” Dr Allaf said. This nuclear imaging technique uses (99m) Tc-sestamibi single-photon emission computed tomography (SPECT)/CT to differentiate oncocytomas and hybrid oncocytic/chromophobe tumors from other renal tumors.3 In a study of 50 patients with solid clinical T1 renal mass, sestamibi imaging demonstrated an overall sensitivity of 87.5% and a specificity of 95.2%.
According to Dr Allaf, one advantage of this noninvasive biopsy technique is a limitation of the number of unnecessary surgeries for patients found to have benign tumors.
Another approach is percutaneous biopsy, which will be discussed at the general session by Alessandro Volpe, MD, associate professor of urology at the University of Easter Piedmont and chairman of the division of urology at the Maggiore della Carità Hospital in Italy.
Historically, percutaneous biopsy was limited by concerns of safety. During the past 10 years, however, interest in percutaneous biopsy has increased as clinicians seek less invasive strategies and prefer to avoid unnecessary surgical treatment.4 The overall accuracy is estimated at over 90%, with a study of over 2000 renal masses indicating a technical failure rate of 5%, sensitivity of 92%, and specificity of 90%.
