Your Need-to-Know Guide to Cancer Terminology

If you have been diagnosed with cancer, one of the first things your medical team will want to determine is the extent to which the cancer has grown. Is it localized to one tiny spot, or has it become metastatic cancer and spread? Cancer develops through a series of mutations, and additional mutations cause it to move to distant parts of the body. Determining your cancer's mobility will help your medical team identify which course of treatment is most beneficial to you.

Here's the need-to-know cancer terminology:

Cancer In Situ

Let's start with the term for a cancer that's staying in one place: cancer in situ, denoting an immobile tumor at the time of classification. In situ is Latin for "confined to the site of origin." Keep in mind, however, that this term is used for early-stage cancers that have yet to spread elsewhere. Therefore, just because a cancer is declared in situ does not mean it won't eventually spread.

Invasive Cancer

Most of us know that cancer can spread, making the situation more difficult for the patient and medical team. Invasive, or infiltrating, cancer is a general term for cancer that's growing and spreading into surrounding areas. The cancer cells rapidly replicate themselves as the tumor reaches other local-area tissues and organs outside of their place of origin.

Metastatic Cancer

What separates metastatic cancer from invasive cancer is that the cancer is spreading from one organ or body part to another area that is not directly connected to the place of origin. The cancer has branched out, is mobile in the body, and is able to move around to distant sites. Metastatic cancers are classified based on the primary tumor, so if breast cancer metastasizes to the bones, the tumor is made of mutated breast cells, not mutated bone cells.

This understanding informs treatment plans, because most cancers that have spread to distant locations are not considered curable. There are several treatment options available, though, to extend and improve quality of life.

Micro-Metastases to the Lymph Nodes

Micro-metastases is different from a diagnosis of metastatic cancer. Instead, it refers to the detection of a small amount of malignant cells in the lymph nodes. To know what makes this notable, you need to have a basic understanding of the lymphatic system. It consists of lymph fluid, which surrounds all the body's cells and functions as part of the immune and waste management systems; the lymph channels, which are like blood vessels that transport the lymph through the body; and the lymph nodes, which function both to filter out waste and as a pump to keep the fluid moving.

So, how does the lymphatic system relate to cancer? Cancer cells often become mobile by breaking off into the lymph fluid or bloodstream and allowing the circulatory system to transport them to other parts of the body. When a cancer cell gets into the lymphatic system, the lymph channels carry it to a lymph node. This cancer cell has been prevented from traveling to other parts of the body, but now it's trapped in the lymph node and may settle in and start dividing and growing. This may grow into a lump that can be felt under the skin in a location apart from the primary tumor, but because of its place in the lymph node, it's not considered to be metastatic.

What If My Cancer Is Metastatic?

When your cancer is found to be metastatic, your medical team will shift how they approach your cancer by bringing in strategies used for dealing with chronic conditions. With a primary cancer tumor, a short-term high-magnitude approach is employed with the goal of eliminating all the cancer in the local area. The body cannot sustain this intensity of treatment over a long period, so rather than addressing a widespread disease with sustained high-intensity treatments for metastatic cases, the plan focuses more on using the least amount of treatment to garner the highest impact.

Your medical team will focus more on helping you maintain your strength and live well with the disease. Each case is individual, and there are many elements, such as the rate of cancer growth and how it reacts to treatment, that affect the extent to which metastatic cancer will affect your life. You don't have to think of metastatic cancer as a further setback, as many people have lived with it for decades. By understanding the terminology involved, you'll be ready to roll with the needed treatment your medical team prescribes.