Being Well

Understand How Secondary Cancer Differs From Primary Cancer

Patient getting CT scan to check for cancer
Secondary cancers are a separate diagnosis of cancer, unrelated to your first diagnosis. A second cancer can develop months or years after your first diagnosis and can happen more often with age. Be proactive and get routine screenings. How frequently you are screened and what screenings you need should be determined by your doctor.

Sometimes you battle cancer only to face a second diagnosis later on. This second round with cancer can come months or even years after the first. One immediate assumption is often that this new cancer is related to the first. That’s not always true. In some cases, you can be diagnosed with a cancer unrelated to a previous diagnosis. This is called secondary cancer or second primary cancer.

Primary and Secondary Cancer Defined

Naming and describing cancer can get surprisingly complicated. Your first diagnosis of cancer is named by the part of the body where it started and is considered primary cancer. Even if the cancer metastasizes (or spreads) to another part of the body, the disease is always referred to by its original site. For example, if you’re diagnosed with breast cancer, but it spreads to your lungs, the disease is still breast cancer. This is because the cells that have spread are still breast cancer cells; they look and act the same, despite being found in your lungs.

A secondary cancer, however, is a new diagnosis of cancer. Even if you’ve had breast cancer, but get diagnosed again with breast cancer, it may be a second cancer. This means the cells look and act differently than they did the first time.

Causes of Secondary Cancer

Aging is one of the main risk factors for cancer in general, and it’s also a factor in developing a second cancer. The National Comprehensive Cancer Network cites skin cancer as a common second diagnosis, but a new cancer can occur anywhere.

Children who survived a childhood cancer, such as leukemia or Hodgkin lymphoma, are at higher risk of developing a second cancer as an adult. Chemotherapy drugs and radiation used to treat these cancers can damage healthy cells and lead to another form of malignancy down the road. Treatment-related second cancers are less common in adult survivors, but it does happen.

Other risk factors include genetic or inherited syndromes that increase your susceptibility to developing cancer as well as certain lifestyle factors. You probably know by now that many of your lifestyle habits can contribute to cancer. Continuing bad habits after a primary cancer can increase your risk of developing a second type of cancer.

When survivors develop secondary cancer that is in the same organ or near the site of their primary cancer, it can be a result of field cancerization. This occurs when surrounding tissues or cells are exposed to the same things that led to the initial diagnosis, so they already have changes that can lead to cancer again, explains the American Cancer Society.

Treatment and Prevention

Treatment for a second diagnosis is based on the profile of that cancer and follows current treatment standards. You and your doctor can talk about treatment options and the risks of chemotherapy or radiation. Your doctor will also consider any genetic basis or inherited syndrome that may have led to the cancer and base treatment on those factors.

The best way to prevent a secondary cancer is to change any poor lifestyle habits that contributed to the first diagnosis and to regularly get screened for cancer. The earlier you find cancer, whether it’s the first or second time, the easier it is to treat.

Having already battled the disease, you may be at higher risk of developing a secondary cancer. Get screened regularly for many types of cancer to catch new developments early.

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Patricia Chaney
Patricia Chaney