ON THIS PAGE: You will learn about how doctors describe a cancer’s growth or spread and its appearance under a microscope. This is called the stage and grade. Use the menu to see other pages.
Grading and staging are ways of describing how fast-growing the cancer is and how much it has grown. This includes where the cancer is located and if or where it has spread. Doctors use diagnostic tests to find out the cancer's grade and stage. So, grading and staging may not be complete until all the tests are finished. Knowing the grade and stage helps the doctor to decide what kind of treatment is best and helps predict a patient's prognosis, which is the chance of recovery. A lower grade or stage cancer is associated with a better chance of recovery than a higher grade or stage cancer.
One way doctors describe penile cancer is by grade (G). The grade describes how much the cancer cells look like healthy cells when viewed under a microscope. The cancer’s grade is important because it helps predict how likely it is to spread to the lymph nodes in the groin. And this information helps the doctor plan treatment.
To determine the cancer’s grade, the doctor compares the cancerous tissue with healthy tissue. Healthy tissue usually has many different types of cells grouped together. If the 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.
TNM staging system
In addition to the grade, staging is another way to determine a patient’s prognosis and help guide treatment. In general, early-stage cancers are linked with a better prognosis and may need less intense treatment than later-stage cancers.
One tool that doctors use to describe the stage is the TNM system. Doctors use the results from diagnostic tests and scans to answer these questions:
- 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? What is the grade of the tumor (see Grades above)?
- Node (N): Has the tumor spread to lymph nodes? If so, where and how many?
- Metastasis (M): Has the cancer spread to other parts of the body or to lymph nodes beyond the groin and pelvis? If so, where and how much?
The results are combined to determine the stage of cancer for each man. There are 5 stages: stage 0 (zero) and stages I through IV (1 through 4). The stage provides a common way of describing the cancer so doctors can work together to plan the best treatments.
Here are more details on each part of the TNM system for penile cancer:
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 centimeter is roughly equal to the width of a standard pen or pencil.
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:
TX: The primary tumor cannot be evaluated.
T0 (T plus zero): There is no tumor.
Tis: An early, noninvasive precancerous growth. This is also called carcinoma in situ.
Ta: A noninvasive squamous cell carcinoma located in only 1 area.
T1: The tumor has grown into 1 of 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:
- T1a: The tumor has not grown into blood vessels, lymph vessels, or nerves and is not high grade or G3 (see above).
- T1b: The tumor has grown into blood vessels, lymph vessels, and/or nerves and is high grade (G3).
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.
T3: The tumor has grown into the corpora cavernosum, an internal chamber of the penis. It may or may not have grown into the urethra.
T4: The tumor has grown into other nearby structures such as the pubic bone, the scrotum, or the prostate.
The “N” in the TNM staging system stands for lymph nodes near the 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.
pNX: The regional lymph nodes cannot be evaluated.
pN0: Cancer has not spread to the regional lymph nodes.
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.
pN2: Cancer has spread to 3 or more inguinal lymph nodes on 1 or both sides of the body.
pN3: The cancer has grown from the inguinal lymph nodes into the surrounding tissue in the groin, and/or the cancer has spread to lymph nodes in the pelvis.
The “M” in the TNM system describes whether the cancer has spread from the penis to other parts of the body, called distant metastasis.
M0: There is no distant metastasis.
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 the cancer by combining the T, N, and M classifications.
Stage I: A 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).
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).
Stage IIB: The 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).
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).
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 to distant parts of the body (T1, T2, or T3; N2, M0).
Stage IV: Any of the following:
The cancer has grown into nearby tissues such as the pubic bone, the scrotum, or the prostate (T4, any N, any M).
The cancer has grown from the groin lymph nodes into the surrounding tissue (any T, N3, any M).
The cancer has spread to 1 or more of the pelvic lymph nodes (any T, N3, any M).
The cancer has spread to distant parts of the body (any T, any N, M1).
Recurrent: Recurrent cancer is cancer that has come back after treatment. If the cancer does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original diagnosis.
Used with permission of the American College of Surgeons, Chicago, Illinois. The original and primary source for this information is the AJCC Cancer Staging Manual, Eighth Edition (2017), published by Springer International Publishing.
Information about the cancer’s stage will help the doctor recommend a specific treatment plan. The next section in this guide is Types of Treatment. Use the menu to choose a different section to read in this guide.