Cancer glossary: 13 terms to know about your diagnosis

If you or a loved one have recently been diagnosed with cancer, you may be hearing a lot of terms like stage, grade, prognosis or minimal residual disease. Even if you’ve heard terms related to cancer diagnosis and treatment before, it’s important to make sure you fully understand what they mean.

“There are a lot of personal choices that come with a cancer diagnosis,” says breast medical oncologist Ajit Bisen, M.D. “So, patients and their loved ones should educate themselves as much as possible to make the right decisions for them. Not all cancer is the same, and best treatment should always be tailored for the individual patient.”

Understanding these terms can better help you prepare for treatment and shape your cancer experience. Here, Bisen defines thirteen common cancer words all patients and caregivers should know.

Prognosis: An estimate of how successful treatment will be based on data from previous patients who’ve had similar diagnoses and treatment. Although prognosis isn’t a guarantee, it gives a ballpark idea of life expectancy. This helps patients and their care team work together to decide the best treatment to meet a patient’s goals for care. For some patients, that means working toward no evidence of disease, but for other patients, it may mean managing cancer pain or even attending a granddaughter’s wedding this summer.

Grade: How fast cancer cells divide and a tumor grows based on the appearance of tumor cells viewed by pathologists under a microscope. The faster cancer cells multiply, the higher the grade. If the cells are doubling rapidly, a small tumor could have a higher grade than a large tumor with cells that aren’t multiplying as quickly. A cancer’s grade helps define its stage in some cancers, like breast cancer.

Stage: Refers to how much a cancer has spread from its original site at the time of diagnosis. Breast cancer and some other cancers can start at stage 0, referred to as carcinoma in situ. But many cancers range from stage I to stage IV. Cancers have strictly defined staging criteria. For breast cancer, staging is calculated based on several factors, like a tumor’s size and grade, how many lymph nodes are affected, and biomarkers, such as estrogen receptor, progesterone receptor, HER-2 expression. Once your care team has determined the type of cancer and its stage, they’ll be able to recommend the best treatment options for you.

Histology: Appearance of tumor cells under a microscope. With a biopsy, a piece of a tumor’s tissue is removed and examined under a microscope to determine the cancer’s unique architecture and appearance. Additional testing is then performed to determine the type and subtype of a cancer.

Disease progression: Cancer is spreading or growing. With solid tumors, this is determined through routine scans during treatment, but some patients become aware of progression as they develop new or worsening symptoms. Some blood tests can also be used to provide more information about disease progression.

Locally advanced: When cancer has spread to lymph nodes near the original tumor site. If cancer has spread to other organs or lymph nodes farther away from the original site, it’s referred to as distant metastatic disease.

Invasive: When cancer is isolated to a specific area, like milk ducts within the breast, it’s considered non-invasive and referred to as in situ. Cancer is considered invasive when it grows beyond the natural architectural boundary of the original tumor site. This will be determined when the pathologist reviews your histology.

Tumor burden: How much cancer you have in your body. Patients with a high tumor burden may have several tumors in different locations throughout the body. Tumor burden is generally used to describe more advanced cancer diagnoses.

Refractory: Describes cancer that isn’t responding to treatment. This may happen at the start of treatment, or the cancer may become resistant to treatment after the patient has undergone several different therapies.

Minimal residual disease: Commonly used with blood cancers like leukemia or lymphoma to refer to very small level of remaining cancer cells. It has a strict testing criteria.  This term is not commonly used for solid tumors. 

Mixed response:  When a patient’s tumors have different responses to the same treatment. Sometimes one tumor site will respond to treatment and get smaller while another tumor elsewhere in the body grows.

Relapsed: Cancer has returned after treatment. This can occur at any time after treatment, but if you experience relapse many years after successful treatment, your care team may want to investigate if this is the same cancer returning or a completely new disease. It’s important to attend your checkups after you’ve completed therapy so your oncologist can monitor for possible relapse.

Resectable/Unresectable: Whether or not a solid tumor can be surgically removed. If a cancer is deemed unresectable, your care team may suggest chemotherapy to shrink a tumor so that it’s easier to be removed surgically.

These are just a few terms you may hear throughout your cancer experience. “If you are ever confused about what your care team shares with you, don’t be afraid to speak up and ask questions,” Bisen says. “Ultimately, you have to trust your care team as your source of information.”

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