Young women who were treated with chest radiation therapy in childhood seem to be unaware of guidelines recommending that they start mammography screening earlier, due to their higher risk of developing cancer, according to a study published in the Journal of the American Medical Association.
In the January 28 issue of JAMA (January 2009, 301:4, pp. 404-414), Dr. Kevin Oeffinger of Memorial Sloan-Kettering Cancer Center in New York City and colleagues published results from a study that found that women treated with chest radiation for a pediatric cancer face increased risk of breast cancer later in life, with the risk of breast cancer increasing as early as eight years after radiation and the median age of breast cancer diagnosis ranging from 32 to 35 years.
"By age 45, about 12% to 20% of women treated with moderate- to high-dose chest radiation in childhood will be diagnosed with breast cancer," Oeffinger said.
What's more, nearly half of women in the study cohort were not in compliance with guidelines recommending that they start receiving mammograms beginning at age 25, due to their higher risk of developing breast cancer caused by radiation treatment.
The study included 625 women ages 25 through 50 who had survived childhood cancer, had been treated with chest radiation for that cancer, and were participating in the Childhood Cancer Survivor Study (CCSS), which consisted of long-term cancer survivors who were diagnosed between 1970 and 1986.
Comparisons were made with 639 similarly aged pediatric cancer survivors not treated with chest radiation, and 712 siblings of the CCSS group. Of 1,976 cancer survivors and siblings who were contacted, 87.9% participated.
Of women ages 25 through 39 years who had received chest radiation therapy, only 23.3% had undergone a screening or diagnostic mammogram within the previous year, 36.5% reported receiving a screening mammogram within the past two years, and 47.3% had never had a mammogram.
While most guidelines for average-risk women call for them to begin receiving screening mammograms between the ages of 40 and 50, guidelines for childhood cancer survivors recommend an earlier start date. For example, the Children's Oncology Group (COG) guidelines call for mammography to begin eight years after radiation therapy, or at age 25, whichever is later.
But these guidelines apparently are not being communicated to radiation therapy survivors, according to the JAMA study.
"We expected this cohort of women to have lower screening rates in general," Oeffinger said. "Most are no longer being followed [for their pediatric cancer incidence]. But we were surprised the percentages were that low, particularly that 47% of women in this age group had never had a mammogram at all."
The study found some evidence that as childhood cancer survivors aged, they were becoming more diligent about screening than the overall population: Of women ages 40 to 50 who had received chest radiation therapy as children, 76.5% had received a screening mammogram within the past two years, compared with 70% of the group who had not had chest radiation therapy and 67% of the CCSS sibling group.
But only 52.6% of women in this age group who had undergone chest radiation therapy had received regular screenings (at least two mammograms within four years) -- not much higher than the rate for the women who had not had chest radiation therapy and only modestly higher than the CCSS siblings.
What made the younger childhood cancer survivors who had received screening mammograms get them? Physician recommendation, Oeffinger said.
"If the women had had a recommendation from their physician, they were three times as likely as those who hadn't to have had a screening mammogram," he said. "It's not that the women are avoiding the exam, it's that they and their physicians lack information on the benefits [of breast cancer screening]."
Radiation is a risk to the breast for teenage girls and women in their early 20s, while the breast is "immature" and undifferentiated, perhaps because there are high concentrations of stem cells at these ages in a woman's life, which may be the progenitors of cancer, according to Dr. Daniel Kopans, professor of radiology at Harvard Medical School in Boston. Kopans was not involved in the Memorial Sloan-Kettering study but commented on its findings in an interview with AuntMinnie.com.
"There have been several studies in the past few years of women treated for Hodgkin's disease who received chest radiation and were at very high risk of developing breast cancer," Kopans said. "What's interesting and important is that the major risk was to women who were radiated in their teens or early 20s. Women who were treated after the age of 29 or 30 had no increased risk."
Oeffinger and his team suggested that their study findings should provide an incentive for developing targeted breast cancer screening education programs for this particular group of women. A good place to start is by ensuring that all women treated with chest radiation during childhood receive a cancer treatment summary from their oncologist that outlines what the cancer was, how it was treated, what type of chemotherapy or radiation was used, potential problems that may result from that therapy, and recommendations for further screening, not only for breast cancer but for heart, thyroid, or lung disease.
"What we love to see is when the patient, the cancer center, and the patient's physician are all talking to each other," Oeffinger said. "When everyone's on the same page, patients are more likely to get screening."
By Kate Madden Yee
AuntMinnie.com staff writer
January 27, 2009
Related Reading
Pediatric Hodgkin's survivors face high risk of breast cancer as young adults, December 30, 2008
Female Hodgkin's survivors have greater risk of secondary cancer, October 28, 2008
Childhood cancer survivors have increased risk of developing new malignancies, December 31, 2007
Kids face more problems after beating cancer, July 15, 2004
Copyright © 2009 AuntMinnie.com