Second cancers are on the rise. Nearly 1 in 5 new cases in the U.S. now involves someone who has had the disease before. Cancer recurrence has a different approach from doctors. But when they speak on second cancers, they're referring to cancer occurring in a different tissue type or completely other site in the body, not recurrence or spread of the original tumor. Almost 19% of cancers in the United States are second-or-more cases, according to a recent study. In the 1970s, it was only 9 percent. Over that period, what changed? Could it be lifestyle factors, the rise of obesity contributing to diabetes and other cardiovascular diseases? Over the course of 40 years, that number rose 70%, while the number of second cancers rose 300%. 

More people are surviving cancer and living long enough to be diagnosed with it again. This is mostly due to the fact that the risk of cancer rises as we age. Second cancers also arise from the same genetic mutations or risk factors such as smoking. Some treatments that help people survive one disease such as radiation or chemotherapy can raise the risk of a new cancer forming alter in life. 

The psychological effects of a second cancer are much more traumatizing than the first. The fear is somewhat unknown during a first cancer diagnosis, but a second diagnosis brings that fear back all over again. 

From a medical standpoint, second cancers can pose special challenges and treatment options may be more limited. An example with regards to radiation, it wouldn't be applied to the same area of the body it had previously been applied to. Some drugs also have lifetime dose lmiited to avoid nerve or heart damage. 

Your body has a memory for the radiation or chemotherapy and can't endure too much of the same type. A second cancer means doctors must assess genetic risk to the patient and possibly their family. 

Genetic mutations like the common BRCA1 gene in women with breast cancer needs to be watched carefully post-remission. 

Experts have this advice for cancer survivors:

—Have a formal survivorship plan, a blueprint for the future that includes a detailed summary of the treatment you received and what kind of monitoring is needed.

—Don’t neglect screenings for other forms of cancer besides the one you were treated for. Make sure to get any recommended tests such as colonoscopies, mammograms or HPV or Pap tests.

—If you get a second cancer, “take a deep breath,” Rowland said. Treatments improve every day, and there are more resources, including social media, for support, and doctors are more used to treating cancer more than once.