Kidney Cancer Research
Michael Blute, MD
Differentiating lymph node positive from node negative RCC
A little over 60,000 renal cell carcinoma (RCC) cases occur on a yearly basis in the United States. Approximately 30-45% of all those diagnosed with RCC are advanced or metastatic and can be associated with high morbidity and mortality rates. Lymph node positive RCC represents an advanced stage with survival rates mirroring that of metastatic disease. Today, clinicians will often attempt to radiographically classify lymph node status based on cross-sectional imaging (ie CT scan). However, as previously demonstrated, the sensitivity or predictive quality of CT scanning to diagnosis lymph node metastasis is only 42%. The most effective manner in which to appropriately stage a patient is through retroperitoneal lymph node dissection (RPLND) at the time of radical nephrectomy. While RPLND for advanced/metastatic RCC has yet to show a significant survival benefit, it allows clinicians to accurately stage patients, and consider adjuvant treatment or clinical trial enrollment.
Identifying those with advanced RCC for aggressive surgical management will be important going forward particularly with the changing landscape of new systemic agents. Systemic therapy does not cure patients of RCC, however, it prolongs overall and progression free survival rates. As survival rates improve, patients are living with the development of new metastatic lesions commonly occurring within the retroperitoneum. Thus, it becomes important to select those who would benefit from RPLND at nephrectomy. Furthermore, surgical removal represents the only potential cure for locally advanced and metastatic RCC.
To this end, detecting biomarkers to help identify patients who would most likely benefit from a RPLND at the time of a radical nephrectomy would further advance surgical management of this aggressive disease. We propose to perform immunohistochemical analysis of surgically resected RCC to determine if certain biomarkers stain positive in lymph node positive vs lymph node negative RCC. If a difference is detected among tissue staining, this study may help identify those who harbor lymph node metastases preoperatively who would benefit from an RPLND and spare those who remain low risk.
Li-Ming Su, MD
Differentiating Cancerous Versus Benign Kidney Tumors
Tumors of the kidney are being identified at smaller sizes and earlier stages than years previous due to the wide spread use of CT and MRI scanning (see Figure 1). As a result, this has provided urologists with the opportunity to achieve higher success rates in curing patients with kidney tumors. Despite earlier diagnosis, however, CT and MRI scans are unable to differentiate between benign (i.e. not cancerous) versus cancerous tumors. Furthermore, up to 30% of these small kidney tumors that are surgically removed are later found to be benign. Although a needle biopsy is an option for preoperative diagnosis of such small kidney tumors, it carries the risk of bleeding, infection, transfusion and more importantly the risk of tumor spread. This highlights the importance in exploring efforts at improving the diagnostic accuracy of kidney tumors with preoperative imaging tools.
One set of imaging technologies that may hold promise is that of optical imaging such as Fiberoptic Confocal Endomicroscopy (Figure 2). This imaging tool has shown promise at differentiating biological tissues on the cellular level. Dr. Su is actively collaborating with the Department of Pathology in investigating this technology and studying the appearance of benign and cancerous kidney tissues. The eventual hope is to develop an “optical biopsy” imaging tool to preoperatively determine the nature of a patient’s kidney tumor and to help select which patients are at greatest need for surgery and which can be simply observed and monitored.
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