Radiation therapy to the chest area can be used to treat some types of childhood cancers. Still, children who receive radiation to the chest area may have a much higher risk of breast cancer later in life. Scientists estimate that about 20% of women who got childhood chest radiation will develop breast cancer by age 45. So doctors recommend a specialized breast cancer screening plan starting at an earlier-than-average age for women with a history of radiation therapy to the chest.
The study reviewed here found that many women who got chest radiation therapy to treat childhood cancer are not getting the breast cancer screening they need based on their medical history.
Routine breast cancer screening with a mammogram is recommended starting at age 40 for women with average risk. Because breast cancer risk is much higher in women who received childhood chest radiation therapy, it's recommended that these women get both a mammogram and an MRI (magnetic resonance imaging) study each year, starting at age 25 or 8 years after receiving radiation therapy (whichever happens later).
In the study reviewed here, the researchers asked 625 women treated with chest radiation for childhood cancer whether and how often they were screened for breast cancer during the 2 years before the study. The women were between the ages of 25 and 50 during the study. The researchers compared this screening information with the screening information of the women's sisters, as well as the screening information of other women who were treated for childhood cancer but didn't receive radiation therapy to the chest.
The results:
Some of the biggest successes in cancer care have been in treating childhood cancer. Still, radiation used to treat childhood cancer also may affect normal cells nearby, causing a new, different cancer to develop many years later. Chest radiation therapy can unintentionally alter normal breast cells, increasing the risk that these breast cells may become breast cancer later in life.
If you've been treated for cancer in the past, it's very important that you regularly see a doctor who's familiar with your medical history and understands the special risks you face. Together, you and your doctor can create the counseling and screening plan that's best for you.
NEW YORK, Jan. 27 (MedPage Today) -- Most young women who survived childhood cancer that was treated with chest radiation do not have regular mammograms despite an increased risk of breast cancer, according to data from a large cohort study.
Almost two-thirds of women ages 25 to 39 had not had a screening mammogram in the previous two years, Kevin Oeffinger, M.D., of Memorial Sloan-Kettering Cancer Center here, and colleagues reported in the Jan. 28 issue of the Journal of the American Medical Association.
And almost a fourth of pediatric cancer survivors 40 and older had not undergone mammography in the previous two years.
"Most young women at risk of breast cancer following chest radiation for a pediatric cancer are not being appropriately screened, highlighting the fact that many women and their physicians are unaware of this risk of breast cancer at a young age," said Dr. Oeffinger.
"Ideally, every one of these patients should be involved in a regular screening program," he added.
Chest radiation for a pediatric malignancy increases the risk of breast cancer, beginning as early as eight years after treatment. An estimated 12% to 20% of women treated with moderate- to high-dose chest radiation as a child will develop breast cancer by age 45.
"The risk is comparable to that of women with BRCA mutations," said Dr. Oeffinger.
Since 2003, the Children's Oncology Group has recommended annual mammography for women exposed to ≥20 Gy of chest radiation, starting at age 25 or eight years after radiation therapy, whichever occurs later. The group updated the recommendation in 2008 to include adjunctive breast MRI along with annual screening mammography.
Despite the mammography recommendations, screening practices among female survivors of pediatric cancer remained largely unexplored.
To evaluate those practices, Dr. Oeffinger and colleagues analyzed data from a survey of 625 women who had survived childhood cancer and had received chest radiation as part of their treatment.
The women were 25 to 50 when surveyed during 2005 and 2006. Their responses were compared with those of 639 pediatric cancer survivors who did not receive chest radiation, and 712 siblings of the cancer survivors who had radiation therapy.
Among cancer survivors with a history of chest radiation, 55% reported having a screening mammogram within the previous two years. However, only 36.5% of women ages 25 to 39 had been screened during that time period compared with 76.5% of those 40 to 50.
During the same time interval, 40.5% of survivors without chest radiation and 37% of the sibling cohort had screening mammograms.
The survey results also showed that 47.3% of survivors with a history of chest radiation had never been screened mammographically.
Moreover, barely half (52.6%) of those ages 40 to 50 reported regular screening mammography (twice in the past four years).
A physician recommendation substantially increased the likelihood of screening. Among women who said a physician had recommended mammography, 76% of those 25 to 39 and 87.3% of those 40 to 50 had been screened within the past two years.
In contrast, absence of a physician recommendation was associated with two-year screening rates of 17.6% and 58.3% among the younger and older patients, respectively.
The authors pointed out that "it is likely that women in this cohort, as evidenced by their high adherence to general women's health recommendations, represent a highly motivated and educated group. Thus, our estimates of breast cancer screening rates, although much lower than recommended, may overestimate the rates among the many women in this risk group who are not participants in the CCSS, highlighting low screening rates nationally for pediatric cancer survivors."
In an accompanying editorial, Aliki Taylor, M.D., Ph.D., of the University of Birmingham, and Roger Taylor, M.D., of Swansea University, both in England, pointed out that curative radiation therapy has a less prominent role in contemporary treatment of pediatric malignancies.
Nonetheless, they said, an estimated 20,000 to 25,000 adults remain in the increased-risk category.
The editorialists also pointed out that breast cancer is just one of a host of long-term health issues caused by therapies used to treat cancer in children.
"As the number of adult survivors of childhood cancer increases, appropriate attention will need to be given to these 'survivorship issues' and should include health education and the provision of dedicated long-term follow-up facilities," Drs. Aliki and Roger Taylor said.
"These follow-up programs need to be individualized and guided by the specific late effects associated with particular treatments used for different types of childhood cancer," they said.
They pointed out that the important issues include "the relatively low
uptake of screening mammography in a high-risk population, the importance of clinician recommendation to improve the uptake of screening mammography, and the continuing need to educate clinicians and patients about the risks of breast cancer after chest irradiation in child-
hood through well-designed education programs."
They also noted that the role of MRI should be further explored due to decreased sensitivity of mammography in younger women as well the role of providing screening at no extra cost.
The study was supported by the National Cancer Institute, the Children's Cancer Research Fund, and the St. Jude Children's Research Fund.
Neither the authors nor the editorialists reported potential conflicts of interest.
Primary source: Journal of the American Medical Association Source reference: Oeffinger KC, et al "Breast cancer surveillance practices among women previously treated with chest radiation for a childhood cancer" JAMA 2009; 301: 404-414.Additional source: Journal of the American Medical AssociationSource reference: Taylor AJ, Taylor RE "Surveillance of breast cancer after childhood cancer" JAMA 2009; 301: 435-436.
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