Testicular Cancer staging helps to determine the disease prognosis and to select an appropriate treatment strategy. TNM is the most commonly used system for staging testicular cancer.
“T” stands for “Tumor Size”, “N” for “Lymph Nodes”, “M” for “Metastasis”, and “S” stands for “Serum level of tumor markers”. Numbers and/or letters after T (is, 1, 2, 3, and 4), N (0, 1, 2, and 3), M (0, 1a, and 1b), and S (x, 0, 1, 2, and 3) provide more details about each of these factors.
Once T, N, M, and S categories are determined through different diagnostic techniques, this information is combined to assign an overall stage (from 0 to IV) to the disease.
Tis – The cancer cells are present only in the seminiferous tubules (small tube-like structures inside the testes).
T1 – Tumor limited to testis/epididymis and has invaded up to the tunica albuginea but has not grown into tunica vaginalis or nearby blood vessels/lymphatics.
T2 – Tumor limited to testis/epididymis and has invaded up to the tunica vaginalis or blood vessels/lymphatics involvement by the tumor.
T3 – Tumor has invaded the spermatic cord with or without blood vessels/lymphatics involvement.
T4 – Tumor has invaded the scrotum with or without blood vessels/lymphatics involvement.
N0 – No spread to regional lymph nodes
N1 – Tumor spread to single or multiple regional lymph node(s) none >2 cm in greatest dimension
N2 – Tumor spread to single or multiple regional lymph node(s), any one >2 cm but </=5 cm in greatest dimension
N3 – Tumor spread to lymph node mass >5 cm in greatest dimension
M0 – No spread to non-regional lymph nodes or distant body parts.
M1a – Tumor spread to non-regional lymph nodes or lungs
M1b – Tumor spread to distant sites other than non-regional lymph nodes or lungs
S0 – Normal tumor marker levels.
S1 – Tumor markers are elevated [LDH <1.5 × upper limit of normal, and beta-HCG <5000 mIU/ml, and AFP <1000 ng/ml].
S2 – Tumor markers are elevated (LDH=1.5-10 × upper limit of normal, or beta-HCG=5000-50000 mIU/ml, or AFP=1000-10000 ng/ml).
S3– Tumor markers are elevated [LDH >10 × upper limit of normal, or beta-HCG >50000 mIU/ml, or AFP >10000 ng/ml].
Testicular Cancer Staging
|0||Tis N0 M0 S0|
|IA||T1 N0 M0 S0|
|IB||T2 N0 M0 S0|
|T3 N0 M0 S0|
|T4 N0 M0 S0|
|IS||Any T N0 M0 S1-3|
|IIA||Any T N1 M0 S0-1|
|IIB||Any T N2 M0 S0-1|
|IIC||Any T N3 M0 S0-1|
|IIIA||Any T Any N M1a S0-1|
|IIIB||Any T N1-3 M0 S2|
|Any T Any N M1a S2|
|IIIC||Any T N1-3 M0 S3|
|Any T Any N M1a S3|
|Any T Any N M1b Any S|
Before discussing the staging, let’s understand the NORMAL ANATOMY of testis and surrounding structures.
We now come to the Human testis anatomy. Testis is the rounded structure, that produces sperm and testosterone.
It lies in a pouch called scrotum and it is lined by epididymis.
The duct joining the testis is called as vas deferens. In front of the testis lies the penis, through which urethra passes. It is connected superiorly to the urinary bladder and helps in passing the urine.
If you look at the testis in detail, it is lined by an inner layer called as tunica albuginea and an outer layer, called as tunica vaginalis. At the upper part is epidemic, which joins the vas deferens superiorly.
This covering outside the testis is called as spermatic cord. It is composed of three layers, internal and external spermatic fascia and cremasteric muscle.
And this outermost pouch like covering that holds both the testis is called a scrotum.
In the following video, Cancerbro explains the TNM STAGING of testicular cancer in an easy to understand manner.
So after discussing the normal anatomy of the testis, we now come to the T staging for testicular tumors. This figure shows the T1 stage in which the tumor is limited to the testis. It may invade the tunica albuginea but not the tunica vaginalis. There is no lymphovascular invasion by the tumor.
Next comes the T2 disease. In this, the disease is limited to the testis or epididymis. The tumor may extend through tunica albuginea to involve tunica vaginalis, or there might be the lymphovascular invasion by the tumor.
This figure shows T3 disease in which the tumor infiltrates into the spermatic cord.
And here the tumor infiltrates into the scrotum, called as T4. So after the T staging, comes the N staging or the nodal staging. The absence of regional lymph nodes is called as N0, whereas, the involvement of regional lymph nodes is called as N1, N2 or N3 depending upon the size and the number of the nodes.
These nodal structures called retroperitoneal lymph nodes are the regional lymph nodes for testicular cancer. Their size and number determine the N-stage, that is N1, N2 or N3. After the T and N staging, comes the M staging for testicular cancer. It is called as M1a if there is spread to non-regional lymph nodes, that is, any nodes except retroperitoneal lymph nodes as discussed above, or if there is spread to lungs that are called as pulmonary metastasis.
Whereas spread to the organs than lungs is called as M1b. This figure shows M1a disease due to the involvement of lymph nodes in the mediastinum, this is non-regional lymph nodes because it is outside the retroperitoneum. Similarly, the involvement of inguinal lymph nodes is also M1a disease because it is a non-regional lymph node for testis.
And here, the involvement of supraclavicular lymph node is non-regional. M1a disease also includes the cases with pulmonary metastasis, that is spread of the tumor to lungs. Whereas, spread to the organs of the body other than lung is called as M1b. In this figure spread to liver makes it M1b.
Spread to brain or bones is also M1b. So with this, we come to the end of TNM testicular cancer staging.