NORD gratefully acknowledges Arlene O. Siefker-Radtke, MD, Professor of Genitourinary Medical Oncology, The University of Texas, M. D. Anderson Cancer Center, for assistance in the preparation of this report.
Urachal cancer is a form of cancer that arises in a structure called the urachus. The urachus is a canal that exists when the fetus is developing before birth. This canal runs from the bladder of the fetus to the belly button (umbilicus). It drains the urinary bladder of the fetus. Between the fourth and fifth month of pregnancy, this canal breaks down (degenerates) into a fibrous band of tissue called a ligament. This ligament runs from the belly button to the top of the bladder and is called the median umbilical ligament. Sometimes, there are tissue remnants of the urachus in adults (about 1/3 of adults have urachal tissue remnants). This usually does not cause any problems. However, sometimes these remnants can potentially become cancerous (malignant). Urachal cancer will often extend into surrounding structures like the bladder, and can potentially spread (metastasize) to other areas of the body. The exact, underlying cause of urachal cancer is not fully understood. Surgery is the most common treatment option.
Much about the disorder is not fully understood. Several factors including the small number of identified cases, the lack of large clinical studies, and the possibility of several factors (e.g. genetic and environmental factors) influencing the disorder prevent physicians from developing a complete picture of associated symptoms and prognosis. Therefore, it is important to note that affected individuals may not have all of the symptoms discussed below.
Some individuals may not have any symptoms (asymptomatic), and urachal cancer can develop for months or even years before any symptoms become apparent. The most common symptom associated with urachal cancer is blood in the urine (hematuria). Additional common symptoms include painful or difficult urination (dysuria), abdominal or pelvic pain, and irritative voiding, which means that there are changes in the frequency and urgency of urinating. Sometimes, a mass can be felt above the pubic area (suprapubic mass). A urachal cancer tumor often produces mucus, and some affected individuals will have mucus in their urine (mucinuria).
Less common signs and symptoms include pus in the urine (pyuria), recurrent urinary tract infections, and the discharge of pus, blood, or mucus from the belly button.
Affected individuals also have nonspecific symptoms. These are symptoms that are common to many different disorders and include nausea, vomiting, diarrhea, fatigue, fever, and unintended weight loss.
The exact underlying cause of urachal cancer is unknown. The exact reason normal cells become cancerous is not known. Researchers speculate that multiple factors including genetic and environmental ones play a role in the disorder’s development. Current research suggests that abnormalities of DNA (deoxyribonucleic acid), which is the carrier of the body’s genetic code, are the underlying basis of cellular malignant transformation.
Researchers are studying people with urachal cancer to see whether there are specific gene variations (mutations) that may predispose them to this form of cancer. A predisposition means that a person has a gene or genes for a particular disorder, but will not develop the disorder unless other factors, such as environmental or immunologic ones, trigger the disorder. Determining specific genetic factors in urachal cancer will open up new pathways for research into the treatment.
Risk factors for urachal cancer are not well understood and no definitive risk factors have been identified.
Most urachal cancers are adenocarcinomas. Adenocarcinomas arise from gland cells, which tend to secrete mucus. This is why a urachal tumor sometime produces mucus and why some affected individuals have mucus in the urine.
Urachal cancer is a rare disorder. The exact prevalence and incidence of this form of cancer in the general population is unknown. Rare disorders often go misdiagnosed or undiagnosed making it difficult to determine their true frequency in the general population. Urachal cancer accounts for less than 1% of bladder cancers. Males and females are affected. Most people are in their 40-50s when diagnosed with the disorder.
A diagnosis of urachal cancer is based upon identification of characteristic symptoms, a detailed patient history, a thorough clinical evaluation and a variety of specialized tests. Signs that can indicate urachal cancer include blood in the urine, mucous-producing cells in affected tissue, and a palpable mass near the bladder. Several different criteria for the diagnosis of urachal cancer have been proposed, but there is no consensus in the medical community on specific diagnostic criteria. The diagnosis of urachal cancer remains a challenge and, consequently, is often diagnosed at a late stage.
Clinical Testing and Workup
A variety of tests can be used to aid in making a diagnosis and ruling out other conditions. Some individuals may undergo a cystoscopy. This is a procedure that allows physicians to examine the bladder. A small, thin tube called a cystoscope is run through the tiny tube that carries urine from the body (urethra). The cystoscope has a tiny camera attached to it and allows a physician to view the urethra and the bladder.
Urachal tumors most commonly present as a midline, cystic mass near the dome of the bladder. Specialized imaging techniques, which may include ultrasound, computerized tomography (CT) scanning, and magnetic resonance imaging (MRI), are essential in making the diagnosis. These tests can help to pinpoint the location of a tumor and detect whether the cancer has spread to other areas of the body. These tests can also be very useful in helping physicians plan treatment. During an ultrasound, reflected sound waves are used to create an image of internal organs or structures. During CT scanning, a computer and x-rays are used to create a film showing cross-sectional images of certain tissue structures. An MRI uses a magnetic field and radio waves to produce cross-sectional images of particular organs and bodily tissues.
If a tumor is found, physicians may surgically remove some of the tumor tissue and study it under a microscope (biopsy). The microscopic study of diseased tissue is called histology and will allow physicians to determine whether a tumor is cancerous and what type of cancer it is.
Immunohistochemistry examination may also be performed. This examination involves using antibodies to diagnosis and differentiate cancer. Antibodies are specialized proteins of the immune system that work to help protect the body from foreign substances. Different antibodies react to specific substances, which are collectively called antigens. When doing immunohistochemistry, antibodies are linked to an enzyme or fluorescent dye and exposed to the tissue sample. Specific antibodies will bind to specific antigens and the enzyme or dye will allow physicians to see this under a microscope.
The treatment of urachal cancer is directed toward the specific symptoms that are apparent in each individual. Treatment may require the coordinated efforts of a team of specialists. Specialists in diagnosing and treating cancer (medical oncologists), specialists in diagnosing and treating disorders of the urinary tract (urologists), surgeons, oncology nurses, psychiatrists, and other healthcare professionals may need to systematically and comprehensively plan treatment. Psychosocial support for the entire family is essential as well.
There are no standardized treatment protocols or guidelines for affected individuals. Due to the rarity of the disease, there are no treatment trials that have been tested on a large group of patients. Various treatments have been reported in the medical literature as part of single case reports or small series of patients. Treatment trials would be very helpful to determine the long-term safety and effectiveness of specific medications and treatments for individuals with urachal cancer.
Specific therapeutic procedures and interventions may vary, depending upon numerous factors, such as disease stage; tumor size; specific urachal cancer subtype; the presence or absence of certain symptoms; an individual’s age and general health; and/or other elements. Decisions concerning the use of particular drug regimens and/or other treatments should be made by physicians and other members of the health care team in careful consultation with the patient based upon the specifics of his or her case; a thorough discussion of the potential benefits and risks, including possible side effects and long-term effects; patient preference; and other appropriate factors.
Surgery is the main treatment option for urachal cancer. Complete removal (resection) of the urachus plus complete resection of the navel (umbilicus) and surrounding soft tissue is often done. This is usually combined with partial or complete removal of the bladder (cystectomy). The surgical removal of these structures is done at the same time (en bloc surgery). Partial cystectomy is associated with a higher quality of life and is the preferred method if possible. Sometimes, nearby lymph nodes are also removed (lymphadenopathy), but there is disagreement in the medical literature as to whether this is beneficial.
Urachal cancer that has been successfully treated through surgery can come back (recur). Some affected individuals may need to undergo surgery again. Other individuals may be treated with chemotherapy or radiation therapy. Some individuals with metastatic disease have also been treated with chemotherapy or radiation therapy.
Although there are some individual reports in the medical literature of people being treated with chemotherapy or radiation therapy, their effectiveness and safety for individuals with urachal cancer is unknown. Two chemotherapy regimens that have been used to treat urachal cancer include cisplatin-based combination therapies, which are commonly used to treat bladder cancer, and 5-fluorouracil-based combination therapies. Clinical studies are necessary to determine what role, if any, and how effective and safe such therapies would be for urachal cancer.
Targeted therapies are being explored as potential treatments for individuals with urachal cancer. Target therapies are drugs and other substances that prevent growth and spread of cancer by blocking or inhibiting certain specific molecules (often proteins) that are involved in the development of specific cancers. Generally, targeted therapies are less toxic than other treatments for cancer. More research is necessary to determine what genetic factors (e.g. altered genes) play a role in the development of urachal cancer and what types of targeted therapies may be possible to treat those specific forms of urachal cancer.
Information on current clinical trials is posted on the Internet at https://clinicaltrials.gov/. All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
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