Bladder cancer can present in several forms. One of these is carcinoma in situ (abbreviated CIS), which is an early stage of the disease. Although on the surface it may appear "less severe" because it has not yet invaded deep tissues, it is actually one of the most aggressive forms.

Let's look together at what it means to have bladder carcinoma in situ, how it is discovered, how it is treated, and why it is important to have regular checkups.

Carcinoma in situ is bladder cancer that develops on the inner surface of the organ, that is, in the mucosa lining the inner walls. At this stage: the cells are already cancerous, but have not yet invaded the muscle or deep tissues of the bladder. In other words, it is a localized tumor, but potentially dangerous because it tends to return and evolve if not treated well.

Yes, even though it is not yet ''invasive,'' CIS is considered a high-risk form because:

- It has a high probability of recurrence (i.e., it can come back even after treatment);
- It can become a more advanced cancer if not treated in time;
- It can be difficult to see in the early stages.

According to experts, without treatment, CIS can turn into an invasive cancer in 50-70% of cases.

Carcinoma in situ is often detected incidentally, such as during a urine test or as a result of detecting blood in the urine (hematuria), even when it is not visible to the naked eye. Common symptoms may include: microscopic hematuria, urgent or frequent need to urinate, and burning or discomfort during urination.

The main examinations to find out are:

1. Urinary cytology: urine is examined for cancer cells (early screening cytology test with Urine24 kit).
2. Cystoscopy: an examination with a small camera inserted into the bladder to see inside. Areas affected by CIS may look like reddened or inflamed areas.
3. Biopsy: a small piece of tissue is taken and analyzed under a microscope.
4. Advanced techniques: such as "blue light" (PDD) or "narrow light" (NBI) that help to see lesions better.

The main treatment is intravesical immunotherapy with BCG (Bacillus Calmette-Guerin, a type of attenuated bacterium also used in tuberculosis vaccines).

Here's what the route includes:

1. Tumor removal (TURBT): if necessary, the doctor removes any visible lesions by endoscopy.
2. Instillations with BCG: For about 6 weeks, once a week, a liquid containing BCG is introduced directly into the bladder. This helps the immune system fight cancer cells.
3. Regular checkups: after treatment, frequent examinations are needed to make sure the tumor does not return.

In some cases, if BCG does not work, other drugs may be used directly in the bladder, or-if the tumor persists or worsens-removal of the bladder (radical cystectomy) may be considered, especially in young and healthy patients.

Carcinoma in situ tends to come back. Therefore, even after successful treatment, it is essential to have regular checkups. Usually the doctor schedules:

- A cystoscopy every 3 months for the first 2 years;
- Then every 6 months until 5 years;
- Then every year.

Urinary cytology, or urinalysis to look for cancer cells, is also often done. In some cases, kidneys and urinary tract are also checked with ultrasound or CT scans.