Hereditary RCC: Genetic or Familial RCC
Most people are not surprised that there is no ONE thing called cancer. Tumors in all the organs or invasive cells in the blood or bones are referred to as cancer, but start when cells go wrong, whatever the cause. As soon as you are told you cancer, whatever it, the quest begins to find out exactly which cancer it is. With kidney cancer, or its more melodious name, renal cell carcinoma, there seem to be endless variations on what may be called kidney or renal cancer. To treat it requires a very careful analysis of what is really is, starting with the pathology of the tumor when it is biopsied. With kidney cancer that biopsy is usually done after surgery for the tumor. That biopsy will describe the shapes and type of cell in the tumor, which can be mix of types. And then the real work begins.
A recent article in “European Urology” reviewed the mix of HEREDITARY renal cancers, those that arise due to one’s background. More common are the “sporadic” kidney cancer that could arise out of the blue or in response to some environmental toxin. There are ten Heredity Renal Cancers, or HRCs. My goal is to alert the reader to the possibility that his cancer might be one of these. This would affect treatment, and may suggest the need to test family members.
If you have kidney cancer or RCC, you may be familiar with “clear cell” or “papillary” to refine the description of the cells in the tumors. This may not be the whole story, as those HRCs—the hereditary kinds—may manifest a mix of ways, including as clear cell or papillary histology.
The most common HRC is Von Hippel-Lindau (VHL) disease, with both benign or malignant tumors. RCC can be found in a 24-34% of VHL patients, appearing at mean age 39 years (far younger than non-heredity RCC), and often with multiple tumors and in both kidneys. Cysts which appear not to be malignant must be watched–they have the potential to become malignant over time. Generally they are managed based on the size of the largest of these lesions. Clear cell RCC is the one VHL-related subtype.
Hereditary papillary renal carcinoma (HPRC) is rarer, and typically occurs later in life. Papillary tumors are the only phenotype with HPRC, and patients often develop numerous tiny tumors, 1000 or more. These tumors are considered type 1 papillary renal cell carcinoma (pRCC) with a low nuclear grade, monitored with CT scans, and some do metastasize, though this is rare. The MET gene is implicated in the growth of these tumors.
Hereditary leiomyomatosis and renal cell cancer (HLRCC) is newly identified as a HRC. Rarely do patients develop RCC, but are susceptible to developing multiple leiomylomas, which are generally benign. When there is early onset of HLRCC, then RCC is found in about 20% of those patients. These tumors can be aggressive, and about 2/3 display a papillary pattern. Such tumors tend to be hyper-vascular.
Birt-Hogg-Dube (BHD) syndrome is quite rare, about 1 in 200,000 people, and thereby likely under diagnosed. This raises the risk of developing kidney tumors, which occurs in 25-35% of BHD patients, and at mean age of 50. These tumors have varying histologic subtypes, generally chromophobe RCC or hybrid variants. And there can be variants in the same tumor or within the kidney. There is a risk of metastases, though rare. The characteristic skin lesions of BHD syndrome are not malignant.
Even more rare is Tuberous Sclerosis Complex (TSC), which can manifest itself in renal lesions, cysts and occasionally, RCC, the latter at a young, average age 28. Neurologic complications can accompany this syndrome.
SDHB-associated paraganglioma/phaeochromoytoma is another heredity condition which may give rise to a mix of renal tumor, including clear cell RCC, chromophobe RCC and oncocytomas, i.e., a mix of histologically different types.
An HRCmay be suspected in patients with a family or individual history of renal tumors, in the instance of both kidney having tumors, or one kidney having multiple tumors or in early-onset renal tumor, i.e., under 50 years of age.
Clinical diagnosis can be further refined by genetic testing, and thorough review by an experienced uropathologist is fundamental to the diagnosis. First consideration would be a VHL analysis and genetic analysis of SDHB and FLCN genes, as warranted. Patients with type 1 papillaryRCC should be considered for MET analysis. The presence of clinical symptoms related to any of the syndromes will guide the gene screening. Testing on family members may well be warranted.
With these cancers, it is possible to have multiple lesions and affect both kidneys. Thus, treatment should preserve renal function and control the risk for metastases. Use of ablation to retain maximum renal function may be preferable to partial nephrectomies, for example.
Though these heredity renal cancers arise in a different manner than the more common sporadic RCC, the study of the molecular pathways provide some insight into new therapies for those patients as well. Thanks always to those researchers who help in this struggle for information, as that is essential to provide treatments.
Peggy—Based on the European Urology 2010.