Multiple Cancers & Second Primary Tumors

You have already been treated for cancer once. Now you are told there is cancer somewhere new. That raises a question that sounds technical but decides almost everything that follows. Is this the old cancer, or a different one? The answer changes the treatment, the staging, and the conversation about what to expect. It is worth understanding the difference well enough to ask about it directly.

Metastasis is the original cancer that has spread. Breast cancer in the liver is still breast cancer. It behaves like breast cancer, and it is treated with breast cancer treatments, not liver cancer treatments. Under the microscope, the cells look like the tissue they came from. See metastatic cancer.

Recurrence is the original cancer coming back after a time when no test could find it. The National Cancer Institute says recurrent cancer starts with cancer cells that the first treatment did not fully remove or destroy. It may return in the same place, nearby, or elsewhere in the body.

A second primary cancer is a new cancer in someone who has a history of cancer. NCI states plainly that a second primary cancer is different from a recurrent cancer. It is not the first cancer returning. It is a separate disease.

NCI says metastatic cancer has the same name as the primary cancer. For example, breast cancer that spreads to the lung is called metastatic breast cancer, not lung cancer, and it is treated as stage 4 breast cancer. A second primary cancer is a different matter: it is a new cancer, not the old one spreading or returning. So the label matters for your plan. Ask your care team which one it is. Keeping copies of your records can help.

This is not always obvious, and the decision belongs to your care team. Reasonable questions to ask: Is this a new cancer or the old one? What made you conclude that? Was it biopsied, and can the pathology be reviewed? Does the plan change if it turns out to be the other one?

NCI's Division of Cancer Epidemiology and Genetics says radiotherapy and certain chemotherapies may increase the risk of a second cancer. Researchers are also studying whether factors such as obesity and tobacco use play a role. Some inherited conditions raise sensitivity to the cancer-causing effects of radiation. NCI notes that nearly one in five cancers diagnosed today occurs in someone with a previous cancer diagnosis.

NCI says people who have several different types of cancer, or cancer diagnosed at a young age, may want to talk with a doctor or genetic counselor about genetic testing. It is fair to ask your team about it.

NCI advises people after treatment to stay up to date with screening and to ask their doctor which cancer screenings they should have and when. Ask for a written survivorship care plan. NCI says it can include the type of cancer you had, your pathology reports, the places and dates of each treatment, key lab reports, and a list of signs and symptoms to watch for and possible long-term effects (late effects). If you notice new symptoms, call your care team.

If you are unsure how your current status is being described, remission versus cure may help you frame the question.

• National Cancer Institute — Recurrent Cancer: When Cancer Comes Back
• NCI Division of Cancer Epidemiology and Genetics — Second Primary Cancers Among Cancer Survivors
• National Cancer Institute — Follow-Up Medical Care After Cancer Treatment
• National Cancer Institute — Metastatic Cancer
• National Cancer Institute — Genetic Testing for Inherited Cancer Risk