Understanding Your Risk of Developing Secondary Cancers
You may have heard stories of people who have battled one type of cancer only to develop another, different one (for example, breast cancer and non-Hodgkin's lymphoma). Often people mistake these as naturally being related to the first cancer, or a spread of the first cancer to other areas in the body. However, this is not always the case. These new cancers are sometimes what are called "secondary cancers." They are not metastases, but rather different "second" cancers that are unrelated to the first.
Linda S. Sutton, MD, medical director at Duke Oncology Network, Duke University Health System in Durham, North Carolina, says that developing a secondary cancer from cancer treatment is a relatively rare occurrence. "Certain predispositions like genetic syndromes or hereditary do play a factor, but for the most part, the risk of developing a secondary cancer from treatments including chemotherapy and radiation is very small," Sutton says.
Furthermore, she adds that patients should not cause themselves undue worry about this possibility. "The biggest risk to patients with cancer is the cancer that they are battling. They should follow the treatment plan designed by their oncologist and not worry about other factors." She goes on to say that, "The vast majority of patients are not going to develop a secondary malignancy because of cancer treatment for the original cancer."
For a small percentage of patients—those with specific and rare genetic conditions—approaching their medical treatment may be a bit different. "These patients will be aware of their specific risk factors and their doctors will discuss the increased risks with them," she says.
J. Leonard Lichtenfeld, MD, MACP, deputy chief medical officer for the American Cancer Society's home office in Atlanta, says there are groups of patients that fall into categories that may have increased chances of developing a secondary cancer.
The first group includes patients who had cancer before age 15. He advises that parents should keep accurate medical histories from the beginning of a diagnosis to chronicle medication, treatment, and other factors. The increased risk often results from a hereditary cancer syndrome, treatments performed that may have caused cancer-causing side effects, or the fact that as people age they may develop common cancers, including colon, breast, or prostate cancer. "There is great success treating cancer in children but parents have to stay very involved in their medical treatment as they age," Dr. Lichtenfeld advises. "By having a complete history as children, cancer survivors [as adults] will be in a better position to treat potential problems and health issues."
More generally, Dr. Lichtenfeld says an unrelated cancer may also develop just because of aging. "Most men in their 80s and 90s develop some form of prostate cancer, and if they had colon, lung, or other cancers earlier in their life, it's not that unexpected." Similarly, he says skin cancer is also very prevalent among second-diagnosis situations .
He also says it is advisable to learn about family histories, and get to know this for both sides of the family. "Knowing about genetics is a good base for treatment. Ask questions, talk to relatives, and keep records," he advises.
Dr. Lichtenfeld also says that in addition to lifestyle factors, patients must remember to get screened for those cancers for which early detection has proven useful. "Research continues to show that childhood and adult cancer survivors alike frequently forgo screening, which puts them at increased risk of finding a second cancer at a later stage when it may be more difficult to treat," he added.
The Field Effect of Cancer
Furthermore, Michael J. Naughton, MD, a medical oncologist with Washington University School of Medicine in St. Louis, says that there are several factors that may increase the likelihood of a primary cancer resulting in a secondary cancer. He explains there is a "field effect" with certain types of cancers, particularly in the areas of digestive tract cancers and ovarian, breast, and others, in which changes in uninvolved tissues may be detected. One theory is that because the body's immune system was vulnerable to the development of the first cancer, it may be more susceptible to the development of a second cancer. "There may be a predisposition to genetic factors as well as risk factors that may increase the chance [of developing a second cancer]," he says. Because the cells of certain organs are similar to one another, the same changes (due to carcinogen exposure, aging, diet, etc) that made one area of that organ susceptible to cancer may occur in other areas of that organ, causing those other locations to be at risk for the development of cancer as well.
Past and current treatments, including radiation, chemotherapy, and certain drugs, also have risks associated with developing secondary and unrelated cancers. "Doctors understand the risks and are well aware of the side effects; however, certain risks are part of treatment," he asserts. "This can be challenging and a delicate balance but a logical part of the treatment process for certain types of cancers."
After the successful treatment of cancer, Dr. Sutton says that healthy lifestyle choices such as healthy eating, exercise, not smoking, limiting UV exposure, and limiting alcohol intake will keep a patient on the path of good health. "I also believe that follow-up care with an oncologist is vital," she states. "As an oncologist, I can say that we understand cancer and we are committed to a cancer patient's follow-up care."
Certain variables, including hormonal issues, heredity, immune deficiencies, and medicines needed to treat primary malignancies, may be out of patients' control. But, says Dr. Lichtenfeld, lifestyle choices are within their control. Like Dr. Sutton, he advises that limiting alcohol, not smoking, making healthy food choices, and getting exercise will help ward off risk, although he says that, "Healthy living is proven to reduce some risk, but not all risk."
Dr. Naughton also agrees that above all, limiting alcohol consumption, practicing sensible exposure to the sun, reducing environmental hazards, and not smoking will assist in reducing risks. "Wise lifestyle choices are a good way to reduce risk," he adds. "These are things that are within a person's control."