The kidneys are a pair of bean-shaped organs that sits attached to theback wall of the lower abdomen on either side of the spine. Every day, thekidneys filter about 200 litre of blood to generate 2 litre of excreted waste (composedof excess water, urea, salts, etc.) as urine. Urine collects in the renalpelvis (area at the center of the kidney) and then passes through the ureter,into the bladder, and out of the body through urethra. The kidneys also makehormones that help control blood pressure and signal the bone marrow to makered blood cells when needed.
An adult’s kidney is about 4-5 inches long andweighs between 115-155 grams in females and between 125-170 grams in males. Thestructural and functional unit of kidney is called nephron, which utilizes fourprocesses to alter the blood plasma, which flows to it: filtration,reabsorption, secretion, and excretion. Although most people have 2 kidneys,each works independently.
This means the body can function with less than 1complete kidney. With dialysis, a mechanized filtering process, it is possibleto live without functioning kidneys. Dialysis can be done through the blood,called hemodialysis, or by using the patient’s abdominal cavity, calledperitoneal dialysis.Some of the intrinsic and extrinsic factors; such as the hereditaryrenal cancer syndromes, and excessive smoking and alcohol, respectively canlead to abnormal growth (tumors/ neoplasia) in one or both the kidneys. Kidneytumor can be benign (non-cancerous, can grow but will not spread), indolent(cancerous but rarely spreads to other parts) or malignant (cancerous and canspread to other parts of the body). Malignant tumor can grow out of control andthese tumor cells can spread (metastasize) to distant organs. Most of thekidney cancers are detected before they metastasize (spread to near by venousflow or the lymph nodes and thus spread to different tissues and organs of thebody, e.g.
lungs); although in many cases RCC can lead to bone or lung cancer. Cancerscaught early are easier to treat successfully. However, these tumors can growto be quite large before the symptoms appear and the cancer is detected. Kidney cancer is not a single disease; it ismade up of a number of different types of cancer that occur in the kidney.
Eachis caused by a different gene, follows a different clinical course, has adifferent histology, and responds differently to therapy (2). The most commontype of kidney cancer in adults is renal cell carcinoma (RCC) and in childrenis Wilms (also called nephroblastoma) tumor, which majorly are unilateral in origin(tumor present in only one kidney) and only in 5% of the cases they may bebilateral (tumor develops in both the kidneys). RCC originates in the lining oftubules, located in the kidney and contributes to about 90 percent of all kidneycancers. The remaining 10 percent of kidney cancers start in the renal pelvislocated in the center of the kidney, which is where urine collects. Globally RCCis the 7th and 9th most common malignancy in men and women, respectively andcontributes to 6% of all cancers with an incidence peak between 60-70 years ofage (1). Kidney cancer has a high incidence rate but has attracted littlepublic health attention because of its low ranking among other cancers as acause of death. Riskfactors The common risk factorsidentified in RCC include several environmental, clinical and genetic factors.
Major risk factors include cigarette smoking, alcohol use, over use of painrelievers containing phenacetin, hypertension and obesity (with increased bodyweight being directly proportional to RCC incidence). Some of the occupationaland environmental factors are extended exposure to cadmium, asbestos, petroleumproducts, ionizing radiations, and acetaminophen abuse). Clinically thepatients with acquired cystic kidney disease (ACKD) and hepatitis C appear tohave an increased risk of developing RCC masses (1).
RCC is also associatedwith numerous hereditary diseases such as (Von Hippel-Lindau disease,hereditary leiomyomatosis RCC, Birt-Hogg-Dube ? syndrome, hereditary papillaryRCC, hereditary nonpolyposis colorectal cancer syndrome, and autosomal dominantpolycystic kidney disease) (1). KidneyCancer SymptomsThe classictriad symptoms for renal cancer are flank pain, palpable abdominal mass, andgross hematuria is rare (6–10%), and these signs typically arise at an advancedstage with aggressive histology (1). Some other less specific symptoms areconstant tiredness, rapid and unexplained weight loss, and fever not caused bya cold or flu. Paraneoplastic (caused dueto the humoral factors secreted by the cancer) syndromes are found inapproximately 30% of patients with symptomatic RCCs. A few symptomatic patientspresent with symptoms caused by metastatic disease, such as bone pain orpersistent cough (1).
When such clinical symptoms as well as arousingvaricocele (enlargement of veins in scrotum) or bilateral lower extremityoedema (excess collection of body fluid) are present, radiologicalinvestigation should be applied.