Frequently Asked Questions

How does cancer grow and spread?

Cancer is an extremely difficult disease to treat because of its growth process. In normal cells, the ability to replicate is controlled by signals that come from outside the cell and enter through the cell membrane. Cancer cells have the unique ability to generate their own signals to further growth. In addition, cancer cells are able to disrupt many signals designed to stop normal cell division.⁹

Cancer cells also include mutations that allow them to avert normal control signals that would cause the cell to die or limit its replication cycles. The ability of cancer cells to grow is bolstered by angiogenesis, the process by which new blood vessels created. As cancer cells replicate and begin to form a tumour, they require oxygen and waste removal—in essence, these cells need access to blood vessels. Cancer cells have the ability to release their own angiogenic factors that start the creation of new blood vessels and suppress angiogenic inhibitors that limit such activity.¹⁰

Once a tumour establishes itself, its cancer cells can metastasize, the process by which cells break away from the original tumour site and move to another site via the blood vessels feeding the tumour.¹⁰

How common is kidney cancer?

Kidney cancers account for approximately 2% of all cancers.¹¹ Lung cancer, in comparison, is the most prevalent form of cancer, accounting for 12% of all cancers. Data from the International Agency for Research on Cancer (IARC) show that 208,000 cases of all kidney cancer types were reported worldwide in 2002, with more than 102,000 deaths.¹¹To put this in perspective, the leading causes of cancer-related mortality are lung cancer (almost 1.2 million deaths per year), stomach cancer (700,000), liver cancer (598,000), and colorectal cancer (almost 529,000).¹¹

What is advanced renal cell carcinoma (RCC)?

The most common form of kidney cancer, advanced RCC, accounts for 90% of cancerous kidney tumours in adults and usually develops in one kidney as a solitary lesion. Rare forms of cancer that affect the kidneys include transitional cell cancer and Wilms' tumour, an embryonic malignancy.¹²

Advanced RCC and other forms of kidney cancer strike men almost twice as often as women and are most common in more developed countries.^11,¹²

Are there different types of advanced RCC?

There are five classifications of advanced RCC based on its location within the kidney (Figure 1), listed from least aggressive to most aggressive¹²:

Oncocytic: located in the cortical collecting tubule, this type of advanced RCC consists of large epithelial cells derived from the collecting duct that contains vast numbers of mitochondria; accounts for 3% to 4% of cases and usually behaves in a benign fashion
Chromophobic: located in the cortical collecting tubule, this type of advanced RCC consists of cells that are resistant to the staining process used in the laboratory setting; accounts for 4% to 6% of cases and is generally accompanied with an excellent prognosis
Chromophilic: located in the proximal tubule, this type of advanced RCC consists of cells that are easily stained; accounts for 12% to 14% of advanced RCC cases, and commonly manifests as a small, manageable, early stage tumour
Clear-cell: located in the proximal tubule, this type of advanced RCC consists of cells with cytoplasm that appears empty; accounts for 75% to 85% of advanced RCC cases, and has an unfavorable prognosis
Collecting duct (Bellini's duct): located in the medullary collecting tubule, this type of advanced RCC contains white cells that are confined to the collecting duct; accounts for 1% of advanced RCC cases, and is the most aggressive form of the disease

What are the risk factors for advanced RCC?

Several risk factors have been linked to advanced RCC. In particular, smoking has been shown to increase the risk for advanced RCC in a dose-dependent manner and is likely responsible for 25% of advanced RCC cases in women and 30% of cases in men. Other risk factors include obesity, environmental, and occupational factors, including asbestos, cadmium, the industrial solvent trichloroethylene, and certain petroleum products; and long-term abuse of some analgesics.¹³ Hereditary advanced RCC occurs in a relatively small number of cases.

How is advanced RCC diagnosed?

Unfortunately, advanced RCC often remains clinically silent until the tumour is either locally advanced or has metastasized. However, more than 50% of patients will eventually present with haematuria (blood in the urine) and a considerable number will have systemic symptoms such as anaemia, fever, and weight loss.^12,¹³ Growing use of computed tomography (CT) and ultrasound diagnostic tools for unrelated medical conditions have led to increased incidental findings of advanced RCC. Between 25% and 40% of advanced RCC diagnoses are made following incidental detection of a renal mass.¹²

Is recurrence of advanced RCC common?

Approximately 20% to 30% of patients with localized advanced RCC experience recurrence of disease after surgical removal of the primary tumour (radical nephrectomy).¹² The median time to relapse (or recurrence) is 15 to 18 months with 85% of relapses occurring within three years post surgery. Most advanced RCC recurrences primarily involve metastases to the lung, a disease state with a poor prognosis.¹²

What is the best supportive care for advanced RCC?

Supportive care for advanced RCC includes surgery for patients with solitary metastasis, spinal cord compression, or impending/actual fractures in weight-bearing bones. Radiation therapy is also an option for palliation, particularly of painful bone metastases. The frequency of visits or assessments depends on the individual needs of the patient.¹²

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