Kidney cancer is the most serious complication of Birt-Hogg-Dubé syndrome (BHD). There are many different types of kidney cancer. In this toolkit, we explain the different types of kidney cancer and find out if they’ve been reported in BHD.
Kidney Cancer Symptoms
There are often very few symptoms of early-stage kidney cancer. Symptoms are often similar regardless of which type of kidney cancer you have. When symptoms do occur, they include blood in your urine, a lump or swelling in your side and pain in the side or back below the ribs. If you have any of these symptoms (or other kidney cancer symptoms), please see your doctor.
How Do I Know What Type of Kidney Cancer I Have?
Although you may have different scans during your diagnosis, it is not often possible to tell which type of kidney cancer you have from these. Instead, the scans tell the doctors about the size of the tumours and where in the kidney they are located. These scans can also often show if the cancer has spread to other parts of the body. A small sample of the tumour (known as a biopsy) may be taken to confirm the type of kidney cancer. A pathologist will study the sample under a microscope and look for cellular features associated with the different types.
Knowing which type of kidney cancer you have may impact the treatment you receive. Some kidney cancer types grow faster and are more likely to spread than others. However, in some cases you may only find out what type of kidney cancer you have after treatment. Your doctor will always discuss this with you to ensure you receive the best treatment available. Generally, outcomes are good and kidney cancer can be treated successfully. However, the quicker kidney cancer can be identified, the easier it is to be treated.
Kidney Cancer Types
Below we outline some of the types of kidney cancer. Please note this list is not exhaustive and there are other rare kidney cancer types not on this list.
Clear Cell Renal Cell Carcinoma (ccRCC)
This is the most common type of kidney cancer in the general population. The name ‘clear cell’ refers to how the cells look when they are viewed under a microscope. People with VHL tend to get ccRCC.
How does it behave?
ccRCC can be fast or slow growing. If not treated, ccRCC can spread to other parts of the body.
How is it treated?
If found quickly, ccRCC normally responds well to treatment. Treatment depends on several factors including the stage of kidney cancer you have. If possible, surgery is the preferred option. However, you may have types of treatment including immunotherapy and targeted therapies. Sometimes, ablation or radiation may be used. This often occurs when a person cannot have surgery. This can happen if the tumour is close to blood vessels or removing it by surgery will impact kidney function.
Has it been reported in BHD?
Yes, although not common, ccRCC has been reported in people with BHD.
Papillary RCC
This is a type of non-clear cell RCC. The term ‘papillary’ refers to the shape of the tumour. Finger-like projections can be found in most of the tumours. There are two types of papillary RCC. Type 1 is more common than type 2 which is often associated with HLRCC.
How does it behave?
Type 1 grows more slowly than type 2 which is faster growing and more aggressive. If left untreated, papillary RCC may spread.
How is it treated?
The most common treatment strategies for papillary RCC are surgery and radiation therapy. In some cases, where the cancer has spread and surgery is not possible, you may have chemotherapy.
Has it been reported in BHD?
Yes, although not common, papillary RCC has been reported in people with BHD.
Chromophobe RCC
This is a type of non-clear cell RCC. It is the most common type of RCC after ccRCC and papillary RCC in the general population. Under a microscope, the cells appear much larger than other types of kidney cancer cells.
How does it behave?
Chromophobe RCC tends to be slow growing and less aggressive. Although it can still spread to other parts of the body, this is less likely than in ccRCC and papillary RCC.
How is it treated?
If the cancer remains localised (i.e. it has not spread), surgery is the preferred option if available. In BHD, surgery is normally performed when the largest tumour reaches 3 cm. If the cancer has spread, a combination of systemic anti-cancer therapy (treating the whole body) and a type of surgery called cytoreductive surgery may be performed. Common anti-cancer drugs used are sunitinib or everolimus. The aim of cytoreductive surgery is to remove as many cancer cells within the kidney as possible.
Has it been reported in BHD?
Yes, chromophobe RCC is one of the more common types of kidney cancer found in people with BHD.
Oncocytoma
An oncocytoma is a type of tumour that is not cancerous (benign). They are unlikely to become cancerous but there have been reports of this happening in the literature. However, it is not possible to tell if a tumour is cancerous from an imaging scan alone.
How does it behave?
Oncocytomas are slow growing. They are often monitored by regular imaging scans to check their growth over time.
How is it treated?
If they reach a certain size, oncocytomas are normally removed by surgery. In BHD, surgery is normally performed when the largest tumour reaches 3 cm.
Has it been reported in BHD?
Yes, oncocytomas are one of the more common types of kidney tumour found in people with BHD.
Angiomyolipoma
An angiomyolipoma is a type of tumour that is not cancerous (benign). These are tumours that that contain muscle, fat and blood vessels. They are often serious due to the risk of the tumours bursting and bleeding. Unlike many of the tumour types on this list, angiomyolipomas can be clearly seen on ultrasound scans. They are common in people with TSC.
How does it behave?
Angiomyolipomas grow very slowly. Their growth is often monitored regularly by imaging scans. The risk of the tumour bursting and bleeding increases with size.
How is it treated?
If an angiomyolipoma grows larger than 4 cm, treatment may be recommended. You may have surgery, ablation therapy or a procedure called an arterial embolization. This reduces blood flow to the tumour and causes the tumour to shrink. If you have TSC, the preferred treatment is everolimus.
Has it been reported in BHD?
Yes, angiomyolipomas have been reported in people with BHD.
Hybrid Oncocytic/Chromophobe Tumour (HOCT)
HOCT is a type of kidney cancer made up of cells from oncocytomas and chromophobe RCC. It is mainly found in people with BHD although sporadic cases have been reported.
How does it behave?
HOCT is slow growing and is unlikely to spread. There have been rare cases of HOCT spread reported. The growth of HOCT is normally monitored by regular scans.
How is it treated?
HOCT is normally treated by surgery. In BHD, surgery is normally performed when the largest tumour reaches 3 cm.
Has it been reported in BHD?
Yes, this is thought to be the most frequent type of kidney cancer in people with BHD.
Other rare types of kidney cancer include collecting duct RCC, medullary RCC and MiT Family Translocation RCC. To date, none of these cancers have been reported in people with BHD. Some kidney cancers cannot be classified into any of these groups. Unclassified kidney cancers have been reported in people with BHD.
Despite the number of studies and case reports on BHD and kidney cancer, there are still many unknowns. These include how many people with BHD develop kidney cancer and a comprehensive study of the types of kidney cancer found. The BHD Syndrome International Registry (BIRT) aims to answer these questions. We need as many people as possible to join the registry so we can help researchers answer these important questions. Understanding more about BHD and kidney cancer will help guide treatment, from surveillance guidelines through to the development of new treatments or a cure. Join the registry now.
The International Kidney Cancer Coalition is a network of patient organisations that support people with kidney cancer. Find support near you.