Bladder Cancer Stages: Understanding Disease Progression

Bladder cancer is a serious but often highly treatable condition that affects the lining of the bladder, the hollow organ responsible for storing urine. While receiving a cancer diagnosis can be daunting, it is important to understand that bladder cancer, when detected early, has a very favourable prognosis. With advancements in medical technology and treatment options, patients with bladder cancer can approach their journey with a sense of hope and optimism.

Types of bladder cancer

Bladder cancer can be classified into three main types based on the specific cells within the bladder that are affected. Understanding these different types is crucial for determining the most appropriate course of treatment and predicting the likely outcomes.

1. Transitional Cell Carcinoma (TCC) or Urothelial Carcinoma (UC):

TCC, also known as UC, is by far the most common type of bladder cancer, accounting for more than 90% of all cases. This type of cancer originates in the transitional epithelium, or urothelium, which is the innermost layer of the bladder wall. The transitional epithelium comprises specialised cells that can stretch and change shape to accommodate the volumes of urine stored in the bladder. TCC can be further classified as non-invasive (superficial) or invasive, depending on whether the cancer has grown into the deeper layers of the bladder wall.

2. Squamous Cell Carcinoma (SCC):

SCC is a less common type of bladder cancer, accounting for about 5% of all cases. This type of cancer develops in the thin, flat cells known as squamous cells, which can form in the bladder lining as a response to chronic irritation and inflammation. Squamous cells are generally not present in the bladder. Still, they can develop as a result of long-term exposure to certain risk factors, such as chronic bladder infections, bladder stones, or indwelling catheters. SCC tends to be more aggressive than TCC and is often diagnosed at a more advanced stage.

Stages of Bladder Cancer

Staging is a critical aspect of bladder cancer diagnosis and treatment planning. The stage of bladder cancer describes the extent to which the cancer has grown and spread within the bladder and to other parts of the body.

Doctors use the TNM staging system, which assesses the size and extent of the primary tumour (T), the presence or absence of cancer in nearby lymph nodes (N), and whether the cancer has metastasised or spread to distant parts of the body (M).

The following is a detailed breakdown of the different stages of bladder cancer:

Non-Muscle Invasive Bladder Cancer (NMIBC):

• Stage 0a (Ta, N0, M0): This is the earliest stage of bladder cancer, where the cancer is confined to the inner lining of the bladder (urothelium) and has not invaded the connective tissue or muscle layers. The cancer is classified as non-invasive papillary carcinoma (Ta).
• Stage 0is (Tis, N0, M0): In this stage, the cancer is confined to the bladder’s inner lining but appears as a flat, reddish area known as carcinoma in situ (CIS) or flat tumour. CIS is a high-grade, aggressive form of bladder cancer that has a higher risk of progression and recurrence.
• Stage I (T1, N0, M0): The cancer has grown into the connective tissue layer (lamina propria) beneath the bladder lining but has not reached the muscle layer. There is no spread to lymph nodes or distant sites.

Muscle-Invasive Bladder Cancer (MIBC):

• Stage II (T2, N0, M0): The cancer has invaded the muscular wall of the bladder (muscularis propria) but has not extended beyond the bladder or spread to lymph nodes or distant sites.
• Stage III: This stage is divided into two substages:
• Stage IIIA (T3a, T3b, or T4a; N0; M0): The cancer has grown through the muscular wall of the bladder and into the perivesical fat (T3a), or it has spread to nearby structures such as the prostate, uterus, or vagina (T4a). There is no spread to lymph nodes or distant sites.
• Stage IIIB (T1-T4a, N1-N3, M0): The cancer may be of any T stage (T1-T4a) and has spread to one or more regional lymph nodes in the pelvis (N1-N3). There is no distant metastasis.

Advanced or Metastatic Bladder Cancer:

• Stage IVA (T4b, any N, M0; or any T, any N, M1a): The cancer has grown through the bladder wall and into the pelvic or abdominal wall (T4b), and it may or may not have spread to regional lymph nodes. Alternatively, the cancer may be of any T stage and has spread to distant lymph nodes outside the pelvis (M1a).
• Stage IVB (any T, any N, M1b): The cancer has spread to distant body parts, such as the lungs, liver, or bones (M1b). The extent of the primary tumour and lymph node involvement may vary.

Accurately staging bladder cancer is essential for determining the most appropriate treatment options and predicting patient outcomes. Earlier-stage cancers (Stages 0-I) are generally associated with better prognoses. They can often be effectively treated with minimally invasive procedures such as transurethral resection of bladder tumours (TURBT) and intravesical therapies. More advanced stages (Stages II-IV) typically require more aggressive treatments, such as radical cystectomy, chemotherapy, immunotherapy, radiation therapy, or its advanced forms like proton therapy, either alone or in combination.

Conclusion

It is important to note that bladder cancer staging can be complex, and the specific treatment plan will depend on various factors, including the patient’s overall health, age, and personal preferences. Working closely with a multidisciplinary team of healthcare professionals at APCC, including urologists, oncologists, and radiation oncologists, is crucial for developing a personalised treatment plan that offers the best chance of success while maintaining the highest possible quality of life.