Kidney cancer diagnosed and staged

Diagnosis

Work up of a kidney cancer usually starts after the patient develops symptoms, with the exception of those cancers that are found incidentally. The point of all of the tests done prior to treatment of kidney cancer is to determine the extent of disease that is present so that treatment can be adjusted accordingly. This includes documenting the extent of disease both locally, in the tissues and lymph nodes surrounding the kidney, as well as ensuring there is no spread distantly, outside the area of the kidney (called metastases). The most sensitive test to document local disease is the CT scan, which has been shown to predict the tumor extent 90% of patients. MRI scans have been used to ensure the tumor has not involved any of the large blood vessels that are in the vicinity of the kidney. Other tests, including basic laboratory blood tests and analysis of the urinemay be used to evaluate general health and the extend of the cancer. In addition, chest x-ray and bone scan are usually done, to ensure that metastatic spread to the lungs and bones, respectively, has not occurred. To obtain a diagnosis of any cancer, tissue or cells must be examined by a pathologist. Therefore, to obtain a diagnosis of kidney cancer, a biopsy is often obtained by inserting a needle into the presumed tumor mass during a CT scan. However, there are also times that the CT scan and/or MRI is so convincing that the mass is a tumor, that the initial biopsy is done during an open surgical procedure, which is done to ultimately remove the kidney as treatment for the kidney cancer. The most appropriate surgical approach must be determined on an individual basis.

Staging

After all of these tests are performed, the stage of the cancer is known. The staging of a cancer basically describes how much it has grown before the diagnosis has been made, documenting the extent of disease. This is often extremely important in terms of what treatment is offered to each individual patient. Before the staging systems are introduced, we will first describe some of the ways that cancers may grow and spread.

Cancers cause problems because they spread and can disrupt the functioning of normal organs. One way kidney cancer can spread is by local extension to invade through the normal structures. This initially includes the kidney, hence causing hematuria, a mass, and abdominal pain. If more growth occurs, cancer can grow to involve the main vein that leaves the kidney (the renal vein), the large vein that returns blood from the bottom half of the body to the heart (the inferior vena cava), or into other organs-most commonly the adrenal glands which sit atop the kidneys.

Kidney cancer can also spread by accessing the lymphatic system. The lymphatic circulation is a complete circulation system in the body (somewhat like the blood circulatory system) that drains into various lymph nodes. When cancer cells access this lymphatic circulation, they can travel to lymph nodes and start new sites of cancer. This is called lymphatic spread. Kidney cancer can spread, at times, into the lymph nodes surrounding the kidney, called the perirenal lymph nodes.

Kidney cancers can also spread through the bloodstream. Cancer cells gain access to distant organs via the bloodstream and cause distant metastases. Cancers of the kidney generally spread locally into the fat surrounding the kidney, the adrenal glands, or the veins prior to spreading via the lymphatic system or the bloodstream. However, tumors, especially larger tumors, can access the bloodstream and spread to the lungs and bones, most commonly. Kidney tumors have also been known to spread to the testis and ovaries through the testicular or ovarian veins that are in close proximity to the kidney.