‘Cancer’ is not an all-inclusive or singular term. For each location in the body where cancer can occur, whether lung, skin, kidney or elsewhere, there are differences in disease characteristics, and how it can be treated.
Kidney cancer is a unique type of cancer with distinctive characteristics. Detection of kidney cancer is difficult because there are often no obvious signs or symptoms until a tumour may be quite large. Many of the symptoms that might occur – palpable mass, flank pain, or blood in the urine – may become manifest only when the cancer has grown to a large size. These considerations may lead to important delays in diagnosing kidney cancer, which may in turn lead to more advanced disease stage at diagnosis and may undermine treatment efficacy.
Fortunately, the majority of patients with kidney cancer do not belong to this category of patients. Most patients are diagnosed with incidental kidney cancer. This form of kidney cancer is discovered when the individual is being tested for something completely different, by ultrasound, CT scan, or another type of test.
The terms ‘kidney cancer’ and ‘renal cell carcinoma’ are often used interchangeably, but in fact renal cell carcinoma is the most common type of kidney cancer. Renal cell carcinoma includes several types of kidney cancer that are classified according to their appearance under the microscope, which is termed “histological type”. The three most common are the clear cell, chromophobe and papillary types.
Renal cell carcinoma is also classified according to its extent or stage.
Pediatric renal tumours
Types of kidney cancer
Kidney cancer is a term that encompasses many different types of cancer that may arise in the kidney. The kind of kidney cancer that you may have depends on which cells of the kidney became abnormal or cancerous. The best treatment is based upon the type of kidney cancer you have and its size. In very rare cases, kidney cancer may be related to a hereditary disorder such as VHL Syndrome (see Genes, Genetics and Kidney Cancer )
- Clear Cell Renal Cell Carcinoma
- Papillary Renal Cell Carcinoma
- Chromophobe Renal Cell Carcinoma
- Collecting Duct Renal Cell Carcinoma (Bellini Duct Carcinoma)
- Oncocytoma
- Genetic Translocation Cancer
- Renal Medullary Cancer
- Transitional Cell Carcinoma of the Kidney, Renal Pelvis
CLEAR CELL RENAL CELL CARCINOMA
The most common type of kidney cancer is called clear cell renal cell carcinoma (RCC). This accounts for up to 80% of kidney cancer. It is more common in men than women and usually occurs after age 55. Clear cell RCC is thought to arise from the cells that line the kidney tubules where urine is made. Through a microscope, the cells look clear and pale. This type of kidney cancer is usually due to a mutation in the von Hippel Lindau (VHL) gene. There are families with inherited mutations of VHL who develop kidney cancers in addition to other medical problems (see VHL Syndrome below). The majority of people, however, who develop clear cell RCC have a non-inherited or “sporadic” version. As a result of the medical research that has found this gene abnormality, there have been great advances in the treatment of this type of kidney cancer.
PAPILLARY RENAL CELL CARCINOMA
The second most common type is called papillary renal cell carcinoma (RCC). Papillary rcc accounts for about 15% of kidney cancers. The name is from microscopic finger-like projections (called papillae) in some, if not most, of the tumours.
Two main types of Papillary kidney cancer:
Type 1 is generally less aggressive. There is a small subset of people who can inherit this type of papillary renal cell carcinoma. Papillary type I RCC, in both the sporadic and hereditary forms, is associated with a mutation of the MET oncogene. An oncogene is a gene in cells that promotes growth and this cancer is associated with abnormalities of the MET gene.
Type 2 tends to be more aggressive, and in rare cases is part of a hereditary syndrome as well. Papillary type 2 tumors occur both sporadically and in patients who have the familial syndrome of hereditary leiomyomatosis and renal cell carcinoma (HLRCC). The genetic mutation associated with HLRCC is in the gene known as fumarate hydratase (FH).
- Suggested resources:
- Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC) or Reed’s Syndrome : HLRCC Family Alliance
- Hereditary Papillary Renal Cell Carcinoma: https://www.cancer.net/cancer-types/hereditary-papillary-renal-carcinoma
CHROMOPHOBE RENAL CELL CARCINOMA
Chromophobe renal cell carcinoma accounts for about 5% of RCC. Overall this is usually less aggressive than clear cell RCC and is usually confined to the kidney. However there are times it can be more serious and can spread.
- Information on Chromophobe RCC is scarce. Recommended resources include PubMed for recent article
COLLECTING DUCT RENAL CELL CARCINOMA (BELLINI DUCT CARCINOMA)
Collecting duct renal cell carcinoma is a very rare sub type of kidney cancer. The major feature is that the cancer cells can form irregular tubes and starts in a different part of the kidney tubule. This tumour type is very aggressive, and has traditionally been treated with chemotherapy although the best treatment is not yet known.
- Information on Collecting Duct RCC is scarce. Recommended resources include PubMed for recent articles.
ONCOCYTOMA
This accounts for about 5% of renal tumours. An oncocytoma is usually a solitary tumour that is benign. It is often diagnosed on biopsy or pathologically after treatment of presumed RCC . However, a form of oncocytic cancer, chromophobe RCC, can occur.
- Suggested resource: http://www.oncocytoma.info
GENETIC TRANSLOCATION CANCER
Genetic translocation is a distinct form of kidney cancer that can occur in young adults (especially females) and probably children. It may make up approximately one-third of pediatric RCC. This can be diagnosed by special staining (immunohistochemical staining) of tissue from the kidney tumour. There are genetic abnormalities called translocations in the TFE3 gene (Xp11.2 translocation).
Approximately 10% to 15% of translocation RCCs occur in children who had prior chemotherapy for a prior cancer. Therefore translocation RCCs should be added to the list of chemotherapy-associated secondary cancers in children.
RENAL MEDULLARY CANCER
Renal medullary cancer is a rare yet aggressive cancer. It can be found in young adults that have sickle cell trait or rarely sickle cell disease, an inherited disease related to their haemoglobin in their red blood cells. In those with sickle cell trait the person carries one normal copy of the hemoglobin A gene (HbA) and one copy of the hemoglobin A gene harboring the genetic mutation found in sickle cell disease (HbS). These individuals do not have sickle cell disease but can develop kidney disease. These people may show visible (gross) hematuria (blood in the urine), abdominal or back/flank pain, abdominal mass, enlarged lymph nodes and significant weight loss.
TRANSITIONAL CELL CARCINOMA OF THE KIDNEY, RENAL PELVIS
Transitional cell carcinoma (TCC, more recently referred to as urothelial cell carcinoma or UCC) is a type of cancer that typically occurs in the lining of the urinary system – the kidney, bladder, and ureters). It is the most common type of bladder cancer and cancer of the ureter, urethra. It is the second most common type of kidney cancer (following renal cell carcinoma), but accounts for only five to 10 percent of all primary renal malignant tumors. Treatment is similar to that of bladder cancer and includes surgery and sometimes chemotherapy.
- Suggested resource: Bladder Cancer Canada: http://bladdercancercanada.org/en/
Pediatric renal tumours
In children below age 15, RCC is quite rare. In this age group the most common renal cancer is Wilms disease. The next most common types of kidney tumour in children are: Clear cell RCC, clear cell sarcoma and rhabdoid tumours. Clear cell sarcoma is more likely to metastasize (spread) to the lungs, brain or bones than Wilms tumour. It is also more likely than Wilms tumour to come back or recur after treatment.
- Wilms Tumour or Nephroblastoma
- Pediatric Clear Cell Renal Carconoma (RCC)
- Other Pediatric Renal Tumours
WILMS TUMOUR OR NEPHROBLASTOMA
Wilms tumour can occur in families as a result of inherited genes. Most tumours are found in children around 3 years of age. Older children are less likely to get Wilms tumour. Above age 6, these tumours are rare.
People of African descent have the highest rates of Wilms’ tumour. Females are also more likely than males to develop the tumours. About 500 cases per year are diagnosed in the US. Wilms tumour occurs in otherwise healthy children. In 10% of cases occur in children with other developmental abnormalities. These include hemi-hypertrophy (abnormal growth on 1 side of the body) cryptorchidism (the absence of one or both testes from the scrotum), and hypospadias (a birth defect of the urethra in the male where the urinary meatus (opening) is abnormally placed. Symptoms can include abdominal mass, abdominal pain, blood in the urine, and fever of unknown cause.
Global News – interview with
TJ Hodgkinson, CEO Wilms Cancer Foundation
Wilms tumour is a very curable cancer with 90% of patients surviving more than 5 years. It must be stressed that the treatment approach is vital to achieving a good response. A multi-disciplinary team consisting of pediatric specialists (pediatric surgeon/urologist,pediatric oncologist, pediatric radiation oncologist) that have extensive experience treating children with cancer is needed.
More information on the Wilms Cancer Foundation – : www.wilmsfoundation.org
PEDIATRIC CLEAR CELL RENAL CARCINOMA (RCC)
Pediatric clear cell renal carcinoma is a rare disease in children. RCC is more common than Wilms tumour after the age of 10 years. However, it is far less common overall than Wilms tumour. Conventional clear cell renal cell carcinomas make up about 15% of kidney cancers in children.
OTHER PEDIATRIC RENAL TUMOURS
While in young adolescents age 15-19 renal cell carcinoma can account for 2/3 of kidney malignancies. They can present with similar findings as in adults. In this age group papillary renal cancer is more common than in adults. There is a unique type of renal cancer (genetic translocation cancer of the kidney) that can be found in young adults and probably children as well.
