Background
Most renal tumors are diagnosed by diagnostic investigation performed for other medical reason. Traditionally, US, CT and MRI are gold standard for detecting and characterising renal masses. Most renal masses are diagnosed accurately by imaging alone. CT or MRI imaging must be performed before and after administration of intravenous contrast material to demonstrate lesion enhancement. In some cases, contrast-enhanced US can be helpful. In this context, the recently introduced contrast-enhanced ultrasound (CEUS) may provide the opportunity to asses small renal masses (pT1) as well as choose therapeutic plan and follow-up.
Purpose
Objective of this study is to assess the feasibility and diagnostic efficacy of CEUS technique as compared with traditional CT or MRI in detecting and characterizing small renal masses.
Methods and Materials
Consecutive patients with previous detected small renal mass lesion at ultrasound, CT or MRI will be prospectively CEUS by an expert radiologist blinded to CT/MRI result. The imaging result will be compared with CT/MRI and surgical and pathological result in order to asses the sensitivity and specificity in tumor detection and characterization. The diagnostic accuracy (sensitivity, specificity, positive predictive value and negative predictive value) of CEUS will be estimated and compared using ROC curve analysis.
Over the last two decades the incidence of renal cell cancer increased by about 2% in worldwide and in Europe. The incidence varies globally, with the highest rates in developed countries such as North America and Europe and the lowest rates in Asia and Africa. In western European countries this incidence stabilised over the past decades. In 2012 there were approximately 84400 new cases of renal cell tumors and 34700 kidney related deaths in the European Union. [Ferlay J camcer incidence and mortality Eur J Cancer 2013]
Data from United States also show increased incidence.
Therefore, early detection is crucial for improving patient prognosis.
A smaller tumor can be treated with a conservative intention and a better outcome in terms of RF and kidney-surgery related risk as cardiovascular events.
CT/MRI and conventional US are gold standard and more used diagnostic methods. However, CT and MRI with contrast material are invasive, expansive and unachievable for some patients with comorbidity or high risk of adverse sides to contrast.
To date, a reliable, non invasive, imaging method that can be used for diagnosis and follow up of small renal mass has yet to be established.
In this context CEUS may represent a non invasive, more sustainable for patients, tool for characterising and follow up of renal cancer. It might gradually replace the use of more invasive CT and MRI as gold standard for the diagnosis. That would help to decrease the use of more invasive methods as well as costs for patients and national health system.