McLean, VA (written by Liz Szabo/USA Today) -- Children diagnosed with cancer remain at risk from a variety of serious, long-term complications even years after doctors pronounce them cured.
Now, new research shows that girls treated with radiation for pediatric tumors face a later risk of breast cancer that's six to seven times as high as that of other women.
About 24% of women treated with chest radiation for any childhood cancer develop breast cancer by age 50. About 30% of women diagnosed as children with Hodgkin lymphoma - a disease treated with higher doses of chest radiation - develop breast cancer by age 50, according to a study to be presented today in Chicago at the annual meeting of the American Society of Clinical Oncology. An average woman's risk of breast cancer by age 50 is 4%.
In comparison, women who carry a mutation in the gene BRCA1 have a 31% risk of breast cancer by that age, while those with a mutation in the BRCA2 gene have a 10% risk, says study author Chaya Moskowitz of New York's Memorial Sloan-Kettering Cancer Center.
The findings affect not only women who were treated with therapeutic radiation as children, but also the thousands of children and adolescents in treatment today. Nearly 60,000 American women alive today had chest radiation for any pediatric cancer, according to Memorial Sloan-Kettering. About 12,500 children and adolescents are diagnosed with cancer each year.
The research reflects a growing sensitivity that "cure is not enough," says Michael Link, outgoing president of the oncology society. Over the past 50 years, cure rates for young cancer patients have improved from 20% to 80%. But the therapies used to cure children are incredibly toxic.
While doctors have known of the increased breast cancer rates among pediatric survivors for years, Moskowitz says her study is the first to compare their risks with those of BRCA mutation carriers, who are well-known for their high risk of breast cancers. Some women with a strong family history of breast cancer now get genetic testing and, if they carry one of the mutations, undergo mastectomies or ovary-removing surgery to reduce their chance of cancer.
Jeanne Miller, 37, survived Hodgkin lymphoma at age 16, after undergoing 13 months of chemotherapy and six weeks of radiation. Last August, she was diagnosed with breast cancer. Doctors recommended a double mastectomy.
"We need to know how to take care of survivors and change childhood cancer therapies, so this doesn't happen to the next group of survivors," says Lisa Diller of Boston's Dana-Farber Cancer Institute. "Children treated for Hodgkin lymphoma today are treated with therapies that try to maintain the excellent cure rates but use as little radiation as possible."
Miller says she is grateful that doctors caught the tumor at the earliest stage.
The Children's Oncology Group recommends women treated with higher doses of radiation begin breast cancer screenings at age 25, or eight years after finishing radiation, whichever comes later, using both mammograms and MRI, or magnetic resonance imaging. Typically, medical societies recommend women at normal risk for breast cancer begin getting screening at age 40 or 50.
Moskowitz says doctors may need to re-evaluate those guidelines for pediatric cancer survivors. She found that even women given lower doses of therapeutic radiation had a significant risk of breast cancer. That risk may continue to rise, too, as childhood cancer survivors age. Few survived the disease before the 1970s, so many of the first survivors are just hitting middle age.
Miller's doctor gives her regular checkups, she says, because some of the chemo drugs she took are known to damage the heart. Her doctor, study co-author Kevin Oeffinger, also of Memorial Sloan-Kettering, has promised her that breast cancer won't slow her down. Miller, of Fairfield, Conn., says she's back to exercising and is currently enjoying a weekend at the beach. Oeffinger has told her "that this would be a blip on my life's radar screen," Miller says, "and that I would celebrate my 90th birthday."