Grading
The grade expresses how much the cancer cells differ from healthy cells when viewed under the microscope. When cancer cells look like normal tissue, the cancer is called well-differentiated. Conversely, when cancer cells gained features that do not belong to healthy cells of normal tissue, the cancer is called poorly-differentiated; this is a sign of aggressive behaviour with high risk of spreading to lymph nodes and distant organs.
GX: The tumor grade cannot be identified.
G1: Describes cells that look more like healthy tissue cells, called well-differentiated.
G2: The cells are somewhat different from healthy cells, called moderately-differentiated.
G3: Describes tumor cells that look very different from healthy cells. This is called poorly-differentiated or high grade.
Staging
The staging measures the macroscopic extension of the cancer to local, loco-regional, or distant organs. Together with the grading, it is the most important predictor for prognosis. It is usually structured in three sections: T (tumor), N (nodes), and M (metastases). T defines the local extension across penile tissue. N defines the spread to loco-regional lymph nodes. M defines the involvement to other parts of the body.
T stage
TX: The primary tumor cannot be evaluated.
T0: No tumor has been identified.
Tis: An early, non-invasive precancerous growth. This is also called carcinoma in situ.
Ta: A non-invasive squamous-cell carcinoma located in only 1 area, usually the penile skin or foreskin.
T1: The tumor has grown into one or more outer layers of the penis. These may include the lamina propria,the dermis, the dartos fascia, or the connective tissue underneath the skin. This stage may also be divided into 2 substages based on the grade of the tumor and whether it has grown into blood vessels, lymphatic vessels, or nerves:
T1a: The tumor has not grown into blood vessels, lymphatic vessels, or nerves and is not high grade or G3.
T1b: The tumor has grown into blood vessels, lymphatic vessels, and/or nerves and is high grade (G3).
T2: The tumor has grown into the corpus spongiosum. It may or may not have involved the urethra.
T3: The tumor has grown into the corpora cavernosa. It may or may not have involved the urethra.
T4: The tumor has grown into other nearby structures such as the pubic bone, the scrotum, or the prostate.
N stage is usually reported as clinical or pathological. Clinical N stage is provided when staging is based on physical examination, US, CT scan, MRI or other non-invasive assessments. Pathological N stage is provided when there is a histological evidence of lymph node involvement, typically after inguinal and or pelvic lymph node dissection.
Clinical stage definition
cNX: Regional lymph nodes cannot be assessed.
cN0: No palpable or visibly enlarged inguinal lymph nodes.
cN1: Palpable mobile unilateral inguinal lymph node.
cN2: Palpable mobile multiple or bilateral inguinal lymph nodes.
cN3: Palpable fixed inguinal nodal mass or pelvic lymphadenopathy, unilateral or bilateral.
Pathological stage definition
pNX: The regional lymph nodes cannot be evaluated.
pN0: Regional lymph nodes are not involved.
pN1: Metastasis in up to two regional lymph nodes on the same side of the body.
pN2: Metastases in three or more unilateral lymph nodes or bilateral inguinal lymph nodes.
pN3: Extranodal extension of lymph node metastasis or pelvic lymph node(s), unilateral or bilateral.
M stage
M0: No distant metastasis.
M1: Distant metastasis – includes lymph node metastasis outside of the true pelvis in addition to visceral or bone sites.
Cancer stage grouping
The stage of cancer results from the combination of T, N, and M groups.
Classifications may change by time according to new discoveries and updates. The American Joint Committee on Cancer (AJCC) usually provides the updated classification for staging. Currently, the 8th classification is the one which is used on clinical practice.
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