Stages of Kidney Cancer

Executive Summary

The kidney cancer stages help determine the location and metastasis of the tumor. The staging system for kidneys uses diagnostic tests. A TNM staging system is generally used to classify the stages of kidney cancer. There are five stages of kidney cancer involving stage 0, stage I (T1, N0, M0), stage II (T2, N0, M0), stage III (T1 or T2, N1, M0; T3, any N, M0), and stage IV (T4, any N, M0; any T, any N, M1).

Recurrent cancer refers to cancer or tumor growth that comes or recurs back after treatment. If the tumor recurs once again in the body, the doctor may recommend another round of scans and diagnostic tests to learn about it and its extent. Understanding the tumor behavior, deciding the apt treatment strategy, and predicting the prognosis of the patient is essential. Therefore, the information regarding tumor cell type, grade of the tumor, personal information, and occurrence or absence of sweats, fevers, or other signs or symptoms are prognostic factors in kidney cancer.

Stages of Kidney Cancer

The stage and grade of cancerous growth play a vital role in determining the gravity of the cancer condition. Staging describes the location or spot of a cancerous growth or tumor. It also helps explain whether the tumor has spread or metastasized to other parts of the body. And, if so, the parts that have been affected or invaded. Doctors use various diagnostic tools to evaluate the stage of a tumor. The tumor stage can only be determined after completing all the required tests and scans. Knowing the tumor stage is extremely essential in deciding the apt treatment strategy. This is because, staging helps doctors choose the best treatment plan to treat the tumor condition of a patient. It helps them predict the disease prognosis and recovery.

The stage description varies with different types of cancers. There are different types of staging systems available, but the most preferred way to describe the stages of kidney cancer is by using the TNM staging system ^​1​. 

The Staging System

In the staging system, the letter ‘T’ stands for tumor, ‘N’ stands for node and ‘M‘ stands for metastasis.

T (Tumor): The staging system will look for the size of the tumor, how large it is and its location of growth. 

N (Node): In terms of node, it evaluates whether the tumor has metastasized to the surrounding lymph nodes or not. If so, where and how many nodes have been affected?

Metastasis (M): Whether the cancerous growth has metastasized to different parts of the body. If so, which all body parts have been invaded, and to what extent? 

The combination of all these results helps determine the tumor stage of a patient. Usually, a cancer condition has five stages: Stage 0 (zero), Stage I, Stage II, Stage III, and Stage IV. This is a common way of describing almost all types of cancers. Based on these stages, the doctors determine the best treatment plan suiting a person’s condition. 

Tumour (T)

The letter T plus a letter or number from 0 (zero) to 4 is used to represent the size and location of tumour growth. The size of the tumour is measured in centimeters (cm). Staging based on tumours can be divided into many small groups. If there is more than one tumour, the lowercase letter “m” (which stands for “multiple”) is added to the letter T. The following is a list of specific tumour stage information concerning kidney cancer:  

TX

This refers to the primary tumour that cannot be examined or analyzed.

T0 (T plus zero)

It indicates nil or zero evidence of tumor growth is found.

T1

It indicates a tumor found only in the kidney, about 7 centimeters (cm) or less than that at its widest dimension. Such tumors usually do not grow or spread outside their area of origin or invade other body parts. They are known as non-invasive tumors

• T1a: The tumor growth is only found in the kidney and is around 4cm or smaller at its widest area.

• T1b: The tumor growth is limited to the kidney, and its size ranges between 4cm and 7cm in its largest area.

T2

In this, the tumor growth is found only in the kidney, and its size is larger than 7cm at its largest dimension.

• T2a: The tumor is present only in the kidney and is larger than 7cm but not more than 10cm.

• T2b: The tumor is present only inside the kidney and is larger than 10cm.

T3

In this stage, the tumor has grown and spread into major veins in the kidney. And the perinephric tissue, which is fatty connective tissue around the kidneys. But the tumor has not invaded the adrenal gland present on the same side of the body as the tumor growth. The adrenal glands are present atop each kidney and generate hormones like adrenaline vital to regulate blood pressure, heart rate, and other body activities. In this stage, the tumor has not spread beyond the Gerota’s fascia, a tissue envelope surrounding the kidney.

• T3a: the tumor growth has metastasized to the large vein that leads out of the kidney. It is called the renal vein. The tumor is likely to affect the pelvis, calyces, and the fat surrounding it and around the kidney. At this stage, the tumor doesn’t grow beyond the Gerota’s fascia.
• T3b: the tumor has metastasized into the large vein that drains into the heart, called the inferior vena cava. It is located below the diaphragm (a muscle underneath the lungs that assists in breathing).
• T3c: the tumor has extensively spread to the vena cava located above the diaphragm and into the heart’s right atrium or sometimes to the vena cava walls.

T4

This stage indicates extensive metastasis and invasion. The tumor has metastasized to areas beyond the Greota’s fascia of the kidney and spreads into the adrenal gland located on the same side of the body as the tumor. 

Node (N)

The letter N in the staging system stands for lymph nodes. Lymph nodes are tiny, bean-shaped organs in our body that helps fight infections. In the case of kidney cancer, the lymph nodes in and near the kidney area are generally called regional lymph nodes. And those present in other body parts are the distant lymph nodes.

NX: it is unable to evaluate the regional lymph nodes.

N0 (N plus zero): Cancer has not metastasized to the regional lymph nodes.

N1: Cancer has metastasized or spread to regional lymph nodes.

Metastasis (M)

The letter “M” in the TNM staging system stands for Metastasis. It describes whether the tumor has spread or metastasized to other parts of the body. And if so, it is called distant metastasis. The common areas where kidney cancer is likely to spread or invade are the liver, bones, brain, lungs, and distant lymph nodes.

M0 (M plus zero): this means that the tumour has not spread to other body parts.

M1: this indicates metastasis. The tumour has spread to other parts of the body beyond the kidney region.

STAGE GROUPING OF CANCER

Doctors assign the stage of cancer or tumor growth by combining the results of the T, N, and M classifications ^​2​.

Stage I

This indicates a non-invasive tumor (T1) that does not spread or metastasize to the lymph nodes or distant organs (N0). The tumor is around 7cm or smaller and is found only in the kidney. Also, there happens no distant metastasis (M0). [Stage I = (T1, N0, M0)].

Stage II

This stage describes a tumor (T2) with no spread or metastasis to the lymph nodes (N0) or distant metastasis (M0). The tumor size is larger than 7cm—[Stage II: (T2, N0, M0)].

Stage III

stage III has got two conditions:

• This stage indicates a tumor (T1 or T2) of considerable size in the kidney. It has spread to or invaded the regional lymph nodes (N1) but shows nil signs of metastasis to other parts of the body(M0). [(T1 or T2, N1, M0)].
• An aggressive tumor has spread to the prominent veins or perinephric tissue that may or may not have metastasized and affected the regional lymph nodes. The tumor is unlikely is spread to other distant parts of the body—[(T3, any N, M0)].

Stage IV

Stage IV has either of these conditions:

• The tumor has metastasized to areas beyond the Gerota’s fascia of the kidney. And extends into the adrenal gland, present on the same side of the body as the tumor growth. The tumor is likely to affect the lymph nodes, but not other distant parts of the body—[(T4, any N, M0)].
• The tumor has metastasized to any other distant organs of the body, like the bones, lungs, or brain—[(any T, any N, M1)].

RECURRENT CANCER

Recurrent cancer refers to cancer or tumor growth that comes or recurs back after treatment. If the tumor recurs once again in the body, the doctor may recommend another round of scans and diagnostic tests to learn about it and the extent of the recurrence. The scans and tests conducted would be similar to those carried out during the original cancer diagnosis. 

PROGNOSTIC FACTORS

It is essential for the doctors or healthcare team to know and learn as much as possible about the tumor. This information can help them understand the tumor behavior, decide the apt treatment strategy, and predict the patient’s prognosis. The information that they should learn include:

• Tumor Cell type: A clear cell, chromophobe, papillary, or any other kind.
• Grade of the tumor: Grade describes how similar the tumor cells are to the healthy, normal cells of the body.
• Personal information: The activity level, body weight, past medical history etc.
• Occurrence or absence of sweats, fevers, or other signs or symptoms.

References