Cancer Remission Types and Recurrence

What is the definition of cancer remission? Are there different types of remission? If a cancer is in remission, is it cured? Let's take a look at the terms which describe the response of cancer to treatment and what these may mean for you.

Remission of cancer refers to the absence of active disease for a period of at least 1 month. The absence of active disease does not mean that cancer has been cured or even that there are no detectable signs of cancer. There are two types of remission:

Complete remission (or undetectable disease) refers to cancer that has no signs or symptoms, and no evidence of cancer can be found on a physical exam by a doctor or through radiological tests such as a CT scan, MRI, or PET scan. 

With complete remission, some doctors use the terminology "NED"—which stands for "no evidence of disease." A complete remission may also be described as a "complete response."

The term partial remission refers to cancer that is still detectable but has decreased in size (or in the number of cancerous cells as in leukemia.) This may also be described as a tumor that is "controlled" or with the term stable disease. One type of partial remission is called a partial response. A partial response is a remission in which there is at least a 30% reduction in the size of a tumor, which persists for at least 1 month.

While remission can mean the same thing as a complete response or stable disease, depending on the type, the term remission is used more often with blood related cancers such as leukemias and lymphomas and the terms stable disease or no evidence of disease are used more often when describing the response of solid tumors (such as lung cancer, breast cancer, or colon cancer) to treatment.

On rare occasions, however, cancer may go into remission without any treatment directed at cancer. This uncommon occurrence is referred to as the spontaneous remission of cancer.

Spontaneous remissions often occur when someone with cancer has been fighting an infection, and it's thought that the bodies immune system, in this case, fights off cancer. This idea, in fact, is the basis for the newer types of cancer treatments referred to as cancer immunotherapy.

Most remissions occur after cancer has been treated with surgery, chemotherapy, radiation therapy, or one of the newer treatments such as targeted therapy or immunotherapy.

There may still be cancer cells present when cancer is deemed to be in remission, but these cells are not detectable by tests we have available at this time. Unfortunately for most solid tumors, it is rare to use the word cured; if there is a chance cancer could recur—even if the chance is very small—it is usually referred to as a remission (or NED) instead of cured.

If a cancer returns after it has been in remission, it is defined as a recurrence or relapse of that cancer. Tumors in remission may:

• Stay in remission indefinitely.
• Recur and go back into remission in cycles.
• Progress (grow) or spread: The term progressive disease means that a tumor has increased at least 20 percent in size or has spread to other regions of the body.

Why do some cancers come back years or even decades after remission? There are several theories as to why cancers recur following a period of remission. It's thought that even though cancer appears to be "gone," some cancer cells may remain after treatment in a state of dormancy (cancer stem cells,) which persist until conditions are right for the cells to begin growing again.

Since cancer recurrence is the greatest cause of mortality with cancer, researchers are actively looking for methods to decrease the risk. Those who are coping with the fear of cancer recurrence or progression understand all too well this risk, and anxiety about possible relapse or recurrence exists in the heart of many people who have experienced remission.

While remission doesn't mean that a cancer is gone for good (cured) for most cancers (exceptions may include some leukemias and lymphomas) it is a very good sign in many ways. Cancer that has gone into remission, whether complete or partial, is usually responding to whatever treatment has been done. Even when treatment no longer works, however, there are often other ways to treat the tumor should it recur. For some tumors, the progressive use of different treatments when cancer is no longer in remission is allowing oncologists to treat cancer in a way similar to that of many medical conditions—as a chronic disease that will always require treatment but can be kept stable for an extended period of time.