Bladder cancer

What is this ?

The bladder is a hollow organ designed to store urine produced by the kidneys between each urination. The cells of the mucous membrane lining the bladder wall are thus repeatedly exposed to urine and its sometimes-toxic components.

Under this stress, a cell can degenerate and multiply uncontrollably to form a tumor : urothelial carcinoma. Most often, these tumors develop in the bladder, but they can also appear in the upper urinary tract (calyces, pelvis, and ureter), located between the kidney and the bladder.

Worldwide, bladder cancer represents a major health concern, with 573,278 new cases and 212,536 deaths recorded in 2020 (source: Global Cancer Observatory, IARC). It is approximately four times more common in men than in women, but it tends to be more aggressive in women.

The average age at diagnosis is around 73 years (source: Cancer Research UK). In 50 to 70% of cases, it presents as localized, non-muscle-invasive disease. About 30% of patients have localized but muscle-invasive tumors. In 5 to 10% of cases, the disease is metastatic at diagnosis, meaning there are cancerous lesions distant from the bladder (lymph nodes, lungs, bones, etc.).

The most common type is urothelial carcinoma, a tumor that appears on the lining of the bladder.

However, other histologies exist depending on the type of tissue affected by the disease. Examples include squamous cell carcinoma and neuroendocrine carcinoma.

Interview with Professor Morgan Roupret

Causes and risk factors

There are several risk factors for kidney cancer :

• Smoking (60% of cases)
• Occupational exposure to certain chemical substances: aromatic amines used in the manufacture of cosmetics, pharmaceutical products, pesticides, plastics, in the rubber industry, and which are also found in tobacco
• Polycyclic aromatic hydrocarbons used in the tar, tire, or textile industries
• If occupational exposure, even in the past, is suspected, a consultation with a specialist in occupational diseases is recommended
• A history of treatment with radiotherapy in the pelvic area or chemotherapy with cyclophosphamide
• Recurrent cystitis, especially in women
• Urinary schistosomiasis (a parasitic infection) for squamous cell carcinoma

Screening

Currently, there is no validated screening for bladder cancer. In cases of occupational risk, occupational health services may conduct urine surveillance tests.

Symptoms

The main symptom of bladder cancer is hematuria, which is the presence of red blood, often accompanied by clots, in the urine.

Other persistent signs that can lead to a diagnosis include urinary burning or frequent urges to urinate without any doctor identifying a urinary infection.

These signs should be particularly alarming in smokers.

Diagnosis

The first diagnostic test is a bladder ultrasound as well as an ultrasound of the entire urinary tract. This is an easily accessible and non-invasive examination.

To better visualize the upper excretory pathways, a CT urogram can be added. The imaging assessment is combined with a specific urine analysis called urinary cytology. This non-invasive test involves examining a urine sample under a microscope to look for abnormal cells.

Formal confirmation of the diagnosis is obtained through cystoscopy.

This is a direct examination of the bladder using an endoscope (similar to a camera) through natural pathways. This is performed by a urologist.

Cystoscopy also allows for biopsies to confirm or rule out the cancerous nature of abnormalities seen in the ultrasound and/or urinary cytology.

If the tumor is invasive (invading the muscle of the bladder), the evaluation may be completed with a full-body CT scan (TAP: thorax, abdomen, and pelvis).

Treatments

Depending on the stage, the proposed management will differ.

For localized tumors not infiltrating the muscle: the first treatment is the endoscopic resection of the lesion via the transurethral route (natural route). A complementary treatment may be associated with the endoscopic resection: intravesical instillations of chemotherapy (mitomycin C) or immunotherapy (BCG).

For muscle-invasive tumors, the standard treatment is surgery, preceded by what is called "neoadjuvant" chemotherapy, provided there are no contraindications. Various surgical techniques exist. In selected patients, the doctor may consider a bladder preservation strategy. This strategy combines partial surgery, chemotherapy, and radiotherapy.

The treatment of metastatic tumors is based on polychemotherapy. If there is a good response after the first chemotherapy, immunotherapy should be initiated after the end of chemotherapy. If chemotherapy is not an option or if there is a recurrence after it, the doctor may then propose immunotherapy.

Finally, new therapeutic classes are in the process of being approved to complement the therapeutic arsenal, such as antibody-drug conjugates (see the dedicated sheet) or, in certain cases (where the tumor presents specific genetic abnormalities), targeted therapies. For smoking patients, smoking cessation is always beneficial.