In today's article, we'll talk about some of the common malignancies and cancers of the urinary tract. Cancers arising from the urinary tract are as common as other cancers but they affect millions yearly.
Image created by @gamsam. Photo by Franck V. on Unsplash
The human Urinary Tract is divided into the upper and lower urinary tracts.
The Upper Urinary Tract consists of the kidneys and ureters and the Lower Urinary Tract consists of the bladder, prostate and urethra.
There are a lot of cancers affecting the urinary tract, but some of the common ones include
- Nephroblastoma, mostly in children
- Renal cell carcinoma in adults
- Bladder Tumours
- Prostate Cancer
- Penile Cancers
Nephroblastoma (Wilm's Tumour)
Nephroblastoma is the most common intrarenal tumor of childhood and the overall second commonest solid tumor in infancy and childhood. It is the cause of about 8% of all renal tumors.
Cross section of kidneys affected by Nephroblastoma. By The Armed Forces Institute of Pathology - Pathology Education Instructional Resource. Public Domain, Link
The peak age of incidence is 3-4 years and 80% of nephroblastomas occur under the age of 4 years. It is rare in adults.
The presenting symptoms are most frequently an increase in the size of the abdomen or an abdominal mass found incidentally during bathing or on routine physical examination. It is rarely associated with abdominal pain and hematuria (blood in urine).
The mass is usually firm, smooth, not tender, and arises out of the flank.
The cause of Nephroblastoma is unknown. The tumour arises from abnormal proliferation of metanephric blastema. The metanephrogenic blastema or metanephric blastema is one of the two embryological structures that give rise to the kidney, it mostly develops into nephrons, but can also form parts of the collecting duct system.
It is believed that Nephroblastomas arise as a result of abnormalities of development; they are thus congenital.
Nephroblastoma affects less than 50% of the pelvis. Haematuria may be seen in late cases. It is bilateral (affects both kidneys) in about 5-10% of cases. Also, about 1% of cases are familial ( tending to occur in more members of a family than expected by chance alone).
The cardinal feature of Nephroblastoma is the presence of abortive glomerulus.
Some investigations that can be done to confirm a diagnosis include plain X-ray, IVU - Intravenous urogram (a radiological procedure used to visualize abnormalities of the urinary system, including the kidneys, ureters, and bladder), chest X-ray, selective renal angiogram, MRI, ultrasound scan and renal biopsy in very advanced stages.
Example of an IVU immage showing the kidneys, ureters and bladder. By The original uploader was Glitzy queen00 at English Wikipedia. - Transferred from en.wikipedia to Commons., Public Domain, Link
The treatment options for Nephroblastoma varies depending on the stage and severity of the disease
Nephrectomy is a surgical procedure to remove all or part of a kidney. When the whole kidney is removed, it is referred to as radical nephrectomy and partial nephrectomy if only a part of the kidney is removed. A total nephrectomy is needed if the disease is bilateral
Cytotoxic chemotherapy and radiotherapy to the tumor bed or whole abdomen are reserved for those with specific indications based on the age of the patient, the size of the tumor, the histology of the tumor, incomplete removal, preoperative or intraoperative rupture or spill, and histological evidence of extracapsular tumor cells.
In stage I of the disease, the cure rate is as high as 90%. Even when there is pulmonary metastasis the 5 year survival is 50% after proper surgery, chemotherapy and radiotherapy. Local recurrence or distant metastasis is rare after the 2nd year.
Renal Cell Carcinoma
Renal Cell Carcinoma is the most common type of kidney cancer and it a serious disease. It occurs more in males with a predominance of about 1.6:1 male to female ratio. The highest incidence is between 60-80 years and the median age of death is about 70 years.
It occurs mostly among the Scandinavians and in North America; lowest incidence is in Africa but there is no racial differences in the US.
Renal Cell Carcinoma is responsible for about 2% of the overall cancer burden and mortality worldwide. Over 50,000 cases are diagnosed and 13,000 deaths occur annually in the United States.
Majority of Renal Cell Carcinoma occurs sporadically although, tobacco smoking contributes to 24-30% of cases. Tobacco results in a 2-fold increased risk.
Occupational exposure to cadmium, asbestos, petroleum, etc, obesity, hypertension, chronic phenacetin or aspirin use and acquired polycystic kidney disease are all risk factors of the disease.
Acquired polycystic kidney disease due to dialysis results in 30% increase risk.
Also, 2-4% of Renal Cell Carcinoma is associated with an inherited disorder Von Hippel-Lindau disease. It is an acquired dominant familial cancer syndrome of retinal angiomas, CNS hemangioblastomas, pheochromocytomas and clear cell Renal Cell Carcinoma.
It arises from the proximal convoluted tubules of the kidney, sometimes from the duct of Bellini. It may although arise from anywhere but it tends to be polar commonly. Only about 2% of cases are bilateral (affects both kidneys). It may appear golden yellow in initial stages but become brown or red when necrosis (tissue death) sets in.
Section of a kidney showing Renal cell carcinoma. By User:Emmanuelm, CC BY 3.0, Link
Renal Cell Carcinoma has a variety of symptoms, most are asymptomatic. Hematuria (blood in urine) is a common complaint present in about 40% of patients.
The classic triad of the disease includes flank pain, hematuria, and a palpable abdominal mass occurring in 9% of patients.
45% of patients present with localized disease, 25% with locally advanced disease, 30% with metastatic disease.
Investigations for Renal Cell Carcinoma include ultrasound scan to visualize and differentiate solid and cystic lesions, IVU, contrast CT scan to determine the size and location, lymph node involvement and skeletal or visceral metastasis.
MRI is also important to evaluate collecting system and inferior vena cava involvement.
Other routine investigations include arteriography, full blood count, electrolyte, urea and creatinine level, lung function tests, chest x-ray, and electrocardiography to check for metastasis to the lungs.
Treatment options may be medical or surgical.
Surgical options include Nephrectomy which may be radical or partial in bilateral disease, metastatectomy, and arteriography with embolization in advanced disease.
Medical treatment includes the use of Immunotherapy with interferon-alpha and interleukin or Targeted therapy with tyrosine kinase (TK) inhibitors [Sunitinib (Sutent), Sorafenib (Nexavar), mTOR inhibition Temsirolimus] or monoclonal antibody [Bevacizumab (Avastin)].
Bladder tumor is the second commonest genitourinary cancer. It is commoner in whites than blacks. The mean age at diagnosis is 65 years with a higher incidence coastal Kenya, southern Malawi, and Egypt, associated with S. haematobium infection.
Location of bladder cancer. By Blausen Medical Communications, Inc. - Donated via OTRS, see ticket for details, CC BY 3.0, Link
Some factors that may predispose an individual to bladder tumour includes cigarrette smoking (due to arylamine and alpha and beta naphtylamine), occupational exposure to aniline dyes, benzidine, beta naphthylamine and 4-aminobiphenyl. Workers in rubber, petroleum, leather and printing industries are also at risk. Use of artificial sweetners, phenacetine use, cyclophosphamide, schistosomiasis and prolonged catheterization are all risk factors.
The pathogenesis is unknown. Most of the tumors (98%) are epithelial in origin.
There are 3 types of bladder tumours
- Transitional Cell Carcinoma (TCC)
- Squamous Cell Carcinoma
Transitional Cell Carcinoma (TCC) are the commonest. They can be pedunculated or sessile. They range from well to poorly differentiated tumours which are often multiple synchronous/metachronous tumours.
They can spread directly to surrounding tissues or through lymphatics and blood.
Squamous Cell Carcinomas are commoner in Africa. They occur as a result of cell metaplasia and they also range from well to poorly differentiated tumours.
Adenocarcinomas are rare tumours that arise from urachal remnants.
Other bladder tumours include Rhabdomyosarcomas, Sarcomas, Lymphomas and other secondary tumours.
Clinical features include haematuria (gross haematuria i.e. physically visible blood in 85-90% of cases and microscopic haematuria in other cases), dysuria (painful urination), and necroturia (dead tissue passed in urine).
There are usually few signs and symptoms in early stages of the disease.
Investigations that can be done include urinalysis, urine cytology, barbotage markers, ultrasound scan, IVU, CT Scan, MRI, cystoscopy and biopsy.
Treatment options include intravesical therapy (administering drugs directly into the bladder) with BCG/Mitomycin, Radical cystectomy (surgical removal of the bladder) with urinary diversion, Radiotherapy with salvage cystectomy and chemo-radiotherapy with gemcitabine, cisplatin, 5-Florouracil, Cyclophosphamide and adriamycin.
Drug treatment (chemotherapy) into the bladder(Intravesical). By Cancer Research UK - Original email from CRUK, CC BY-SA 4.0, Link
Urethral Carcinomas are very uncommon and most are squamous cell carcinomas.
Prostate Cancer is a common disease among elderly men and we'll explore it fully in the next post.
See you next time.🙂
Do you have any questions, concerns or anything to add? Tell me what you think below.
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- "Wilms Tumor and Other Childhood Kidney Tumors Treatment". National Cancer Institute.
- Avellino GJ, Bose S, Wang DS (June 2016). "Diagnosis and Management of Hematuria". The Surgical Clinics of North America.
- Hodges, Stephanie C.; Holt, Harry R.; Degeorge, Katharine C. (15 October 2017). "Bladder Cancer: Diagnosis and Treatment". American Family Physician.
- Curti, B; Jana, BRP; Javeed, M; Makhoul, I; Sachdeva, K; Hu, W; Perry, M; Talavera, F (26 February 2014). Harris, JE (ed.). "Renal Cell Carcinoma". Medscape Reference. WebMD.
- Lane, Brian R. (2013). "Prognostic Factors for Localized Renal Cell Carcinoma". Renal Cell Carcinoma.
Written by @gamsam - a Medical Student
All images used are copyright free
Vancouver Style was used for References.