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.

Sign of Kidney Cancer

Kidney cancer presents as signs and symptoms of either the local tumor in the kidney or as signs and symptoms resulting from spread of disease to other locations in the body (metastatic disease). Symptoms resulting from local tumor extension include hematuria (blood in the urine), abdominal pain, and a flank mass. Hematuria is the most common symptom and present as either gross hematuria, where the blood is visible in the urine, or as microscopic hematuria, where the blood is only detected by laboratory testing. Therefore, any presence of blood in the urine that is detected in a urine sample should be investigated. In medical textbooks, patients present with the "classic triad" of all three symptoms, though only about 10% of patients actually have all three symptoms at diagnosis.

Symptoms caused by metastatic disease include fever, weight loss, and night sweats (drenching sweats that require changing of clothes or bedsheets). Other symptoms include hypertension, increased calcium in the blood, and liver problems. These more unique symptoms are thought to be caused by chemical signals released by the tumor cells into the bloodstream and the body's reaction to them.

Kidney Cancer

The definition of a tumor is a mass of abnormally growing cells. Tumors can be either benign or malignant. Benign tumors have uncontrolled cell growth, but without any invasion into normal tissues and without any ability to spread to distant parts of the body. A tumor is called malignant, or cancer, if tumor cells gain the propensity to invade tissues and spread locally as well as to distant parts of the body. In this sense, kidney cancer occurs when cells in either the cortex of the kidney or cells in the renal pelvis grow uncontrollably and form tumors that can invade normal tissues and spread to other parts of the body.

Cancers are described by the types of cells from which they arise. Again, when discussing kidney cancer, the cortex and the renal pelvis must be discussed separately. In the kidney cortex, the vast majority of cancers arise from the cells that line the collecting tubules, more specifically, the proximal tubules. Cancers that develop from lining such as this are called carcinomas. In this case, they are called renal cell carcinomas. Over 75% of renal cell carcinomas are called clear cell carcinomas, named after the characteristics they display when looking at them under the microscope. Other classifications, in decreasing order of prevalence, include chromophilic, chromophobic, oncocytic, and collecting duct cancers. However, it does not appear that these various types of renal cell carcinoma differ in presentation or prognosis.

Cancers of the renal pelvis, or medulla, are uncommon. Over 90% of cancers that develop in the renal pelvis are called transitional cell carcinomas. They are so named because they develop from cells that line the renal pelvis and upper ureters.

Am I at risk for kidney cancer?

Kidney cancer occurs in approximately 31,000 Americans per year and cancers of the renal pelvis will occur in approximately 3,000 Americans per year. Most patients are diagnosed between the ages of 50 and 70. Kidney cancer is more common in men than women, with an equal preponderance in whites and blacks. A number of risk factors are associated with an increased probability of renal cell cancer: The most prominent risk is cigarette smoking. Persons who smoke have twice the risk of developing kidney cancer as people who don’t smoke, and smoking is directly responsible for up to one out of every three cancers. The risk for kidney cancer also increases fourfold in persons with a first-degree relative who had kidney cancer. Other, less-proven risk factors include obesity (especially in women), analgesic abuse, high blood pressure, and several uncommon hereditary diseases, including von Hippel-Lindau disease and polycystic kidney disease.