Following are the common causes and risk factors of penile cancer: 

1. Older men, over age 60
2. Smokers
3. Body fluids that get trapped in the foreskin
4. HPV (Human Papillomavirus), a sexually transmitted disease
5. AIDS
6. Men who aren’t circumcised
7. Poor personal hygiene
   

Grades:

Penile cancers are also classified in terms of grade and those are determined by how cells looked under the microscope. To determine cancer’s grade, the doctor compares the cancerous tissue with healthy tissue. Healthy tissue usually has many different types of cells grouped together. If cancer looks similar to healthy tissue and contains different cell groupings, it is called "differentiated" or a "low-grade tumor." If the cancerous tissue looks very different from healthy tissue, it is called "poorly differentiated" or a "high-grade tumor." Higher grade penile cancers are more likely to spread to the lymph nodes and may need more intense treatment.

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.

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TNM System for Penile Cancer:

Penile cancer is staged using the tumor node metastases (TNM) system.

1. A tumor (T): How far has the primary tumor grown into the penis? Has it grown beyond the penis into nearby parts of the body, such as the pubic bone, scrotum, or prostate? 
2. Node (N): Has the tumor spread to lymph nodes? If so, where and how many?
3. Metastasis (M): Has cancer spread to other parts of the body or lymph nodes beyond the groin and pelvis? If so, where and how much?

1. A tumor (T) -

Using the TNM system, the "T" plus a letter and/or number (0 to 4) is used to describe the size and location of the tumor. Tumor size is measured in centimeters (cm). A stage may also be divided into smaller groups that help describe the tumor in even more detail. This helps the doctor develop the best treatment plan for each patient. Specific tumor stage information is listed below:

1. TX: The primary tumor cannot be evaluated.
2. T0 (T plus zero): There is no evidence of a primary tumor in the penis.
3. Tis: This stage is carcinoma in situ. An early, noninvasive precancerous growth. 
4. Ta: This refers to a noninvasive squamous cell carcinoma located in only 1 area.
5. T1: The tumor has grown into 1 or more outer layers of the penis. Depending on where on the penis the cancer is growing, these may include the lamina propria, the layer of skin called 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, lymph vessels, or nerves:

1. T2: The tumor has grown into the corpus spongiosum, an internal chamber of the penis. It may or may not have grown into the urethra.
2. T3: The tumor has grown into the corpora cavernosa, an internal chamber of the penis. It may or may not have grown into the urethra.
3. T4: The tumor has grown into other nearby structures such as the pubic bone, the scrotum, or the prostate.

2. Node (N)-

‍The “N” in the TNM staging system stands for lymph nodes near cancer, called regional lymph nodes. The regional lymph nodes for penile cancer are located in the groin and the pelvis. Lymph nodes in other parts of the body are called distant lymph nodes. Staging places cancers that have spread to regional lymph nodes and cancers that have spread to distant lymph nodes in separate categories. The N in TNM staging only refers to the regional lymph nodes. 

If the doctor evaluates the lymph nodes before the biopsy or surgery, based on a physical examination and/or other tests, the letter “c”, for “clinical” staging, is placed in front of the N. If the doctor evaluates the lymph nodes after a biopsy or surgical removal of the lymph nodes, which is more accurate, the letter “p”, for “pathologic” staging, is placed in front of the N. The information below describes the pathologic staging.

1. pNX: The regional lymph nodes cannot be evaluated.
2. pN0: Cancer has not spread to the regional lymph nodes.
3. pN1: Cancer has spread to 2 or fewer inguinal lymph nodes on the same side of the body. The inguinal lymph nodes are located in the groin.
4. pN2: Cancer has spread to 3 or more inguinal lymph nodes on 1 or both sides of the body.
5. pN3: Cancer has grown from the inguinal lymph nodes into the surrounding tissue in the groin, and/or cancer has spread to lymph nodes in the pelvis.

3. Metastasis (M)- The “M” in the TNM system describes whether cancer has spread from the penis to other parts of the body, called distant metastasis.

1. M0: There is no distant metastasis.
2. M1: There is metastasis to parts of the body other than the penis and the regional lymph nodes.

Cancer Stage Grouping: ‍

Doctors assign the stage of cancer by combining the T, N, and M classifications.

1. Stage I: Low-grade cancer that has grown just below the surface layer of skin but not to nerves, lymph vessels, or blood vessels. It has not spread to lymph nodes or distant parts of the body (T1a, N0, M0).
2. Stage IIA: The cancer is high grade or has grown into blood vessels, lymph vessels, or nerves. Or it has grown into the corpus spongiosum and may or may not have grown into the urethra. It has not spread to lymph nodes or distant parts of the body (T1b or T2; N0, M0).
3. Stage IIB: Cancer has grown into the corpora cavernosum and may or may not have grown into the urethra. It has not spread to lymph nodes or distant parts of the body (T3, N0, M0).
4. Stage IIIA: The tumor has not grown beyond the penis and urethra. It has spread to 1 to 2 groin lymph nodes but not to distant parts of the body (T1, T2, or T3; N1, M0).
5. Stage IIIB: The tumor has not grown beyond the penis and urethra but has spread to 3 or more groin lymph nodes. It has not spread outside the groin lymph nodes, to the pelvic lymph nodes, or distant parts of the body (T1, T2, or T3; N2, M0).
6. Stage IV: Any of the following:
   

The follow-ups are especially important in cases of cancers to manage side-effects and monitor the overall health, recovery progress as well as check for any signs that cancer has come back. So, follow-up care and active monitoring are essential. These include regular physical examinations, medical tests, specific tests of the penis and the lymph nodes in the groin, chest x-rays or CT scans, and blood tests.

Cancer rehabilitation and survivorship care are recommended, and this could mean any of a wide range of services that help people regain control over many aspects of their lives and remain as independent and productive as possible and these services may include physical therapy, career counseling, pain management, nutritional planning, financial counseling, and/or emotional counseling.