A second cancer is a malignancy that develops in someone who has survived an earlier cancer.
Formally referred to as second primary neoplasms, second cancers are also described as late effects of the original disease or of the treatment used to cure it.
Blood-based malignancies usually occur within a few years of treatment. Solid tumors may not become evident until 20 years later. Most second cancers affect parts of the body that have been exposed to radiation and are near the site of the original tumor.
Having once had cancer almost doubles an individual's risk of having cancer a second time. A child who develops cancer before the age of 15 is eight times more susceptible to a new cancer than a boy or girl the same age who has not had the disease. Age does not seem to decrease the likelihood that any cancer survivor will develop a second malignancy.
Each year, almost 100, 000 new malignancies are diagnosed among the more than 8, 000, 000 children, teenagers, and adults who have previously been treated for cancer. Although still rare, the incidence of new cancers in patients cured of one or more malignancies more than doubled (from approximately 6.4% to 15.3%) between 1973 and 1997. The rate of second cancers will continue to rise as the number of long-term cancer survivors continues to grow.
Children who have been treated for Hodgkin's disease are most at risk for developing a second cancer within 20 years. The likelihood is lowest for individuals who survive five years or longer after being treated for non-Hodgkin's lymphoma .
Some second cancers result from the risk factors responsible for the original disease. Some are caused by radiation or chemotherapy treatments that damage normal cells or suppress the patient's immune system.
Chemotherapy generally increases the likelihood of leukemia. Radiation raises the risk of developing breast cancer or other solid tumors.
Scientists do not fully understand why chemotherapy causes some cancer survivors to develop new malignancies. They believe radiation's role in second cancers is influenced by:
- the kind of radiation exposure the patient receives
- how much radiation the patient receives
- how old the patient is at the time of treatment
- the patient's personal and family medical history
Although second cancers can occur following treatment for any type of cancer, researchers are concentrating on:
- testicular cancer
because these are the diseases that most often affect children and young adults.
Researchers are also trying to determine which types of cell damage can be characterized as precancerous and how:
- the patient's gender
- the patient's age at the time of diagnosis
- the stage of the original cancer at the time of diagnosis
- the length of the patient's survival affect the risk of developing a second cancer.
Other studies focus on whether administering both radiation and chemotherapy raises or lowers a patient's risk of developing a second cancer and how:
- specific chemotherapy drugs
- the number of times a patient is exposed to radiation
- the total amount of radiation a patient receives during a course of treatment
affect the chances of developing a new malignancy.
In 1993, the National Cancer Institute (NCI) initiated the Childhood Cancer Survivor Study (CCSS). The most extensive study of its kind ever undertaken, the ongoing investigation involves more than 20, 000 patients diagnosed with cancer before the age of 21. It is designed to:
- provide new information about long-term effects of cancer and cancer treatments
- enable doctors to design treatments that increase survival rates and reduce the incidence and severity of unpleasant or harmful side effects
- help survivors understand how diagnosis and treatment can continue to affect their health
- implement programs for the prevention and early detection of second cancers and other late effects
In 1996, NCI established an Office of Cancer Survivorship (OCS) to identify and provide education and support for the special physical and emotional needs of cancer survivors.
OCS's mission is improving cancer survivors' quality of life. Priority research focuses on increasing awareness of the challenges associated with cancer survivorship and developing programs to lessen the burdens of cancer survivors.
NCI's Pediatric Oncology Branch conducts clinical trials for children whose cancer has recurred or has not responded to treatment.
- investigating the process that transforms cancer treatments into sources of new tumors
- studying ways to maintain or improve survival rates while treating patients with gentler types of chemotherapy or doses of radiation too low to inflict the cell damage that causes second cancers
- confident that further research into causes of second cancers will enable them to develop strategies to prevent the development of new malignancies
Even though only a small percentage of cancer survivors develop second malignancies, everyone who has had cancer must:
- follow a healthy lifestyle
- avoid known causes of cancer, like smoking or prolonged exposure to the sun
- diligently follow their doctor's recommendations regarding cancer screenings and other forms of medical surveillance
- see a doctor as soon as they develop new symptoms or notice any changes in the way they look or feel
Improved long-term cancer survival rates have increased concern about the physical and psychological effects of the disease and the treatments used to cure it.
Doctors must monitor cancer patients carefully to make sure radiation and chemotherapy dosages low enough to eliminate unwanted side effects are strong enough to eradicate all a patient's cancer cells.
A patient who has had cancer should be aware of the risk of developing a second cancer. However, patients should not refuse or discontinue treatment for fear of developing a second malignancy. The benefits of cancer treatment far outweigh the risk of developing a new cancer.
Division of Cancer Control and Population Sciences, National Cancer Institute. 6130 Executive Blvd., Executive Plaza North, Rockeville, MD 20852. (301) 594-6776. <http://dccps.nci.nih.gov/ocs>.
National Childhood Cancer Foundation. 440 E. Huntington Dr., PO Box 60012, Arcadia, CA 91066-6012. (800) 458-NCCF. <http://www.nccf.org/NCCF/Advocacy/program.asp>.
Key cancer statistics. National Cancer Institute. <http://search.nci.nih.gov/search97cgi/s97_cgi>.29 April 2001
Long-term follow-up study. University of Minnesota. 10 April 2001. <http://www.cancer.umn.edu/ltfu>.27 April 2001.
Platz, Elizabeth A., et al. Second cancers. Cancer medicine. <http://www.cancernetwork.com/canmed/ch188/188-0.htm>.
—A consequence of illness or therapy that becomes evident only after long-term patient monitoring.
—A new, abnormal growth of tissue. A neoplasm may be benign or malignant.
—A cancer that originates in an organ or tissue rather than in bone marrow or the lymph system.
QUESTIONS TO ASK THE DOCTOR
- Am I likely to develop a second cancer?
- How can I reduce my risk of developing a second cancer?
- What symptoms might mean that I have developed a new cancer?
- What should I do if any of these symptoms occur?