The Language Of Cancer
If you or a loved one has cancer, it is important that you understand your doctor when talking about your disease.
By Nancy Volkers
InteliHealth Staff Writer
InteliHealth Staff Writer
Oncologists — doctors who treat cancer — use many terms when they talk about this disease. These terms usually have very specific meanings that are important in cancer research, specifically in clinical trials. Your doctor may also use these terms when talking to you.
If you or a loved one has cancer, you may want to become well versed in the language of cancer. As a start, get to know some of the more common cancer terms listed below. However, if your doctor uses terminology that you don't understand, don't hesitate to ask him or her for a definition or an explanation. Effective communication is essential when talking about your health.
- Progressive disease
- Refractory cancer
- Complete remission
- Partial remission
- Resistant cancer
- Complete response
- Partial response
- Stable disease
- Disease-free survival
- Disease-specific survival
- Event-free survival
- Progression-free survival
- Relative survival
- Total survival
For more information, see Interpreting Cancer Statistics.
Cure. When it comes to cancer, the word "cure" is a tricky one. Oncologists are usually hesitant to say that someone is cured of cancer, because there is always a chance the cancer can come back. Even if all the cancer seems to be gone, there may be some undetected cells still in the body. These cells can multiply over time and lead to relapse.
If someone is described as cured, it usually means that he or she has been cancer-free for at least five years.
Progressive disease. Progressive disease is defined in clinical trials as tumor growth of more than 20 percent since treatment began. Tumor growth means that the tumor is getting bigger, but it may also mean that the tumor is spreading. Progression generally indicates that treatment has stopped working. The bottom line is that your cancer is getting worse.
Recurrence, or relapse. If your doctor tells you that you are experiencing a recurrence, or relapse, of cancer, this means that cancer you thought had been successfully treated has now returned. The cancer may have returned in its original location, or it may be in a new location.
Even if you are in remission — that is, your cancer seems to have disappeared — some cancer cells may still be present, and they can multiply over time. A recurrence, or relapse, may not be detected until tests identify these cells.
Refractory cancer, or resistant cancer. For many reasons, cancer may not respond to treatment. Some cancer cells have ways of defending themselves against chemotherapy drugs, biological agents and/or radiation therapy. In such cases, the cancer is termed refractory. Refractory cancer may shrink, but not to the point where the treatment is determined to be effective. In most cases, the tumor stays the same size it was before treatment (stable disease) or it grows (progressive disease).
Remission, complete remission or complete response. After your cancer has been treated, your doctor will do some tests to see if any cancer cells are still present in your body. If your doctor can't find any cancer cells over the course of six months, you are thought to be in remission (a situation also known as a complete remission or a complete response). This does not mean the cancer has disappeared completely. It means only that no cells have been found after testing.
Remission may last for many years, or for less than one year. You should continue to follow up with your doctor and get tested regularly to see if any cancer cells remain in your body.
Partial remission, or partial response. A partial remission, or partial response, indicates there has been a decrease in tumor size, or in the extent of cancer in the body, after treatment. The definition of "partial" is different for every cancer. In most cases it means tumors must be reduced by more than 50 percent — and stay that way for at least six months after treatment. But in clinical trials, new guidelines define a partial response as a reduction in tumor size of at least 30 percent.
Stable disease. A tumor may shrink, but not enough to be categorized as a partial response (that is, tumor reduction greater than 50 percent). Or a tumor may increase in size, but not enough to be considered progressive disease (that is, tumor growth greater than 20 percent). Such tumors, in which there is no significant change in size, are classified as stable disease.
Disease-free survival. Disease-free survival is the length of time after treatment that a person experiences a complete remission (in which cancer is not detectable in the body). Disease-free survival can also refer to the percentage of people who experience complete remission for a certain time period. For example, if a cancer treatment results in 70 percent disease-free survival over five years, seven out of every 10 people were in complete remission for five years after treatment.
Disease-specific survival. Disease-specific survival tells you the proportion of people with a type of cancer who did not die of the cancer after a specific time period. These people may still be alive, or they may have died of some other cause. For example, a 60 percent disease-specific survival for a certain type of cancer means that 40 percent of the people with that cancer died of the cancer, and 60 percent either are alive or died of some other cause.
Event-free survival. This term is usually used only in clinical trials. It refers to the length of time after treatment that a person remains free of certain negative events, which can include the following:
- Severe treatment side effects
- Cancer recurrence or progression
- Death (from treatment side effects or from the cancer itself)
The negative events used to calculate event-free survival can vary. They are usually determined by the type of clinical trial conducted.
Progression-free survival. This term defines the length of time during and after treatment that the cancer does not grow. Progression-free survival includes the amount of time patients have experienced a complete response or a partial response, as well as the amount of time patients have experienced stable disease.
Relative survival. Relative survival reflects the expected amount of time a person with a particular disease will live, compared with people the same age who do not have that disease. Relative survival gives you an idea of how much a particular disease is expected to shorten your life.
Relative survival is often expressed as the percent of people with the disease who survive five years, divided by the percent of the general population who will be alive at the end of those five years. For example, the five-year relative survival for breast cancer is 86 percent. Therefore, the proportion of women with breast cancer who are alive five years after diagnosis is 86 percent of the proportion of the general population who are alive five years later. Put another way, five years after diagnosis, the population of women with breast cancer has 14 percent fewer survivors than the general population does, or the chance of a woman being alive five years after a breast cancer diagnosis is 14 percent lower than it is for all women.
Relative survival is usually calculated for specific stages of cancer. Stages reflect how large a tumor is, whether or not it can be surgically removed and whether it has spread to lymph nodes, bone or other organs at the time of diagnosis. This is an informative way to present information, because survival is higher when cancer is diagnosed early than when cancer is diagnosed after it has spread (metastasized).
For example, the overall five-year relative survival for people with lung cancer is 15 percent, but for people with lung cancer that has not spread outside the lung, it is 48 percent. (In contrast, survival for people diagnosed after their lung cancer has spread outside the lung is only 3 percent.)
Relative survival considers only deaths from the cancer and not other deaths (from accidents, heart disease, secondary cancers or other causes).
Total survival. Total survival reflects the expected amount of time a person will live before dying of any cause. Total survival reflects the risk of dying from a specific cancer, plus the risk of dying from any other cause (an accident or another disease, for example). Cancer experts calculate total survival to determine the additional years of life lost as a consequence of having cancer. This has a major impact on choosing treatment.
For example, a 90 year old man with a small colon cancer is much more likely to die of another cause other than colon cancer. So surgery to remove the colon cancer may not be indicated. But a 55 year old with a cancerous colon polyp has a significant risk of dying from metastatic colon cancer if the polyp is not completely removed.