Several different types of cancer can develop in the kidney. Conventional or clear cell renal cell cancer, also known as renal cell carcinoma, is by far the most common type of kidney cancer in adults. Renes is the Latin word for kidney. Renal cell carcinoma accounts for about 85% of cancers arising from the kidney. Renal cell carcinoma develops in the tubules of the kidney, part of the filtering system.It is the most common type of kidney cancer in adults. Initial treatment is surgery. It is notoriously resistant to radiation therapy and chemotherapy, although some cases respond to immunotherapy.
As a group, renal pelvis and ureter cancers account for no more than 5% of all cancers of the kidney and upper urinary tract. They affect men more often than women and are more common in people older than 65.Children are more likely to develop a kind of kidney cancer called Wilms' tumor.
Tumors of the renal pelvis and ureter are usually transitional cell cancers. Approximately 10% are squamous cell carcinomas.Each year, about 32,000 people in the United States are diagnosed with renal cell carcinoma. Of these diagnoses, most occur in people aged 50-70 years, but the disease can occur at any age. About twice as many men as women develop this cancer, and it occurs in all races and ethnic groups.
Like almost all cancers, renal cell cancer is most likely to be successfully treated when it is found early.The likelihood that renal cell cancer will be cured depends on its stage when it is diagnosed and treated. Renal cell cancers found in the early stages are cured over half the time.
Surgical removal of all or part of the kidney ( nephrectomy ) is usually recommended. This may include removal of part of the bladder and surrounding tissues or lymph nodes. If the tumor is in the ureter, it may be possible to remove it while preserving the kidney.
When the cancer has spread outside of the kidney or ureter, chemotherapy is often used. Because these tumors behave similarly to transitional cell carcinoma of the bladder, the chemotherapy regimens used are similar to those used for bladder cancer .
Two new drugs may offer people with metastatic kidney cancer a chance to slow the progression of their disease and perhaps even live longer.
New research, reported in the New England Journal of Medicine, details the phase III clinical trials of the drugs sunitinib and sorafenib -- two compounds that work in a similar manner, suppressing a genetic defect that turns off one of the body's normal tumor-suppressor genes.
The first study found progression-free survival was increased to 11 months for the drug sunitinib, compared to five months for the current standard-care medication interferon alfa, in previously untreated patients with metastatic kidney cancer. The second study found that progression-free survival in patients with metastatic cancer that had already been treated with interferon alfa was increased to 5.5 months if they took the drug sorafenib, compared with 2.8 months for those taking a placebo.
"Kidney cancer has always been regarded as a cancer in which there was no progress," explained the lead author of the sunitinib study, Dr. Robert Motzer, an attending physician at Memorial Sloan-Kettering Cancer Center in New York City. "Based on a better understanding of tumor biology, this new medication (sunitinib) was developed, and it has remarkable activity that has resulted in a complete change in the way we treat this cancer."
Motzer added that sunitinib is now "the new standard of care for metastatic kidney cancer."
Dr. James Brugarolas, an assistant professor of oncology at the University of Texas Southwestern Medical Center at Dallas, said the two new drugs represented "a major step forward in our fight against kidney cancer that was made possible by obtaining a greater understanding of the molecular genetics and biology of the disease. These drugs are clearly effective against the tumor. They make it shrink, but do not make it disappear."
Brugarolas, who wrote an accompanying editorial in the same issue of the journal, added, "We now have three therapies that have been approved by the FDA for kidney cell carcinoma, and the fourth is coming."
Motzer and his colleagues compared the use of sunitinib to what was considered the standard of care at the time, interferon alfa. Their study included 750 patients with metastatic kidney cancer who had previously been untreated.
The study volunteers were randomly assigned to receive either repeated six-week cycles of oral sunitinib or injected interferon alfa three times weekly. Study medications were provided by sunitinib's manufacturer, Pfizer Inc.
Sunitinib had a response rate of 31 percent, versus 6 percent for interferon alfa. The time of progression-free survival was also increased in the sunitinib group -- 11 months compared to five months for the interferon alfa group. Additionally, patients in the sunitinib group also reported a better quality of life than those in the interferon group.
Motzer said the researchers didn't design the study to look at survival time as an endpoint, and that it may be difficult to get such data from this trial, because many of those on interferon alfa later switched to sunitinib.
The second study focused on treating patients who had already been unsuccessfully treated with interferon alfa. This study included 903 people with metastatic kidney cancer who were randomly selected to receive either oral sorafenib or a placebo. The researchers reported receiving support from Bayer and Onyx Pharmaceuticals, the makers of sorafenib.
Partial responses -- considered the best response in this trial -- were reported in 10 percent of those taking sorafenib, versus only 2 percent of those on a placebo. The average progression-free survival was 5.5 months for the sorafenib group, compared to 2.8 months for those in the placebo group.
Both drugs, as with most cancer-fighting medications, can have serious side effects. Diarrhea, skin rash or sores and increased blood pressure were some of the adverse effects of both drugs.
"Both drugs have the capacity to slow down or shrink the tumor size. Clearly, they have activity against the tumor, and I expect that will translate to improvements in life expectancy, but the data isn't available yet," said Brugarolas, who pointed out that the toxicity of the drugs may affect any gains in life expectancy.
While both drugs work in a similar manner, affecting the genetic mutation that turns off a tumor-suppressing gene, both Brugarolas and Motzer said they couldn't compare the two medications because they haven't been tested in head-to-head trials, and they've both been studied in different patient populations.
Kidney cancer seldom causes problems in its early stages. But as a tumor grows, you may notice blood in your urine or experience unintentional weight loss or back pain that doesn't go away. Kidney cancer cells may also spread (metastasize) outside your kidneys to nearby organs as well as to more distant sites in the body. Yet if kidney cancer is detected and treated early, the chances for a full recovery are good.
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