Bladder Cancer TNM Staging System Explained

Video Transcript:

Consider this to be a cross section from the wall of the urinary bladder, with the upper part being the inside of the wall and lower part being the inside of the wall and lower part being outside. The innermost layer is called the epithelium outer to which lies this layer called as lamina propria. Outer to lamina propria lies this layer, called an inner muscle layer. And on the outermost aspect lies the outer muscle layer.

So after discussing this normal anatomy of the bladder, let’s have a look at the T-staging for bladder cancer. TIS is the carcinoma in situ which is a flat tumor limited to the epithelium. Ans Ta is the papillary tumor which is limited to the epithelium. Both Tis and Ta are the non-invasive sub-types of bladder cancer. When the tumor infiltrates into the lamina propria it is called T1.

When it infiltrates into the inner muscle layer, it is called as T2a. And T2b when it infiltrates into the outer muscle layer. Till T2 the tumor is limited to the bladder wall, but when the tumor infiltrates through the bladder wall to involve the perivesical tissue it is called as T3 disease. And in T4 disease, the tumor infiltrates through the bladder wall to involve the adjacent structures. It may extend downwards to infiltrate prostate gland in male, as you can see in this figure.

Whereas in females, it may extend posteriorly to involve the uterus or vagina. It may also extend laterally to involve the pelvic or abdominal wall. This finishes the T staging for bladder cancer. Now, let’s come to the N staging or the nodal staging. This figure shows the pelvic and iliac group of lymph nodes which are the regional lymph nodes for the bladder. Depending upon the number and location of the lymph nodes involved, it can be N1, N2, or N3.

Now let’s come to the M staging or the metastatic staging for the bladder cancer st. Distant metastases from bladder cancer may occur to the bones. Or to the liver in the form of multiple nodular deposits.

It may also spread to one or both the lungs as seen in this figure. Or to the peritoneum in form of multiple peritoneal deposits. So with this, we come to the end of Bladder cancer TNM staging.

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