What are second cancers?

Advances in cancer early detection and treatment mean that more and more people are surviving cancer today. Cancer survivors can be affected by a number of health problems, but often their greatest concern is facing cancer again. If a cancer comes back after treatment it is called a recurrence. But some cancer survivors may develop a new, unrelated cancer later. This is called a second cancer. No matter what type of cancer you have had, it is still possible to get another (new) cancer, even after surviving the first.

For people with some types of cancer, the risk of getting certain other types of cancer is clearly higher, but for other types it’s not as clear if the risk is increased. Because it can take many years for cancers to develop, second cancers have been studied best in types of cancers for which successful treatments have been around the longest. That’s why we know more about second cancers after certain types of cancer than for others..

Often, second cancers seem to happen more often than would be expected just based on how common cancer is. Sometimes the new cancer is in the same organ as the first. For example, someone who was treated for colon cancer can get another colon cancer. Others occur in other organs or tissues.

What causes second cancers?

It isn’t always clear what causes second cancers. Some seem to be caused by the same things that caused the first cancer. Others may be caused by cancer treatment.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: December 11, 2014 Last Revised: December 11, 2014

American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.