Examine | Mammography: Taking Care After Cancer

Cancer survivors avoid breast cancer screening

One would think that a woman who had endured the trauma of a childhood cancer would be extra vigilant about standard cancer screening, but new research shows that many female survivors are avoiding their annual mammograms.

Female childhood cancer survivors who have had chest radiation are strongly advised by medical experts to receive mammograms even earlier than the general population of women, as they present a significantly higher risk for breast cancer. However, according to several studies completed in 2009, almost half of female childhood cancer survivors under the age of 40 who had chest radiation as part of their treatment are not following this advice.

While it may seem strange to many in the imaging community that these women and their doctors would be negligent enough to ignore a possibly dire health risk, many experts acknowledge that the standard mammogram for detecting preinvasive and invasive breast cancer is known to be relatively poor in young women due to the density of breast tissue in this age group.

Moreover, for those that are well informed about current screening practices, there is a prevalent fear of the unknown. For example, screening mammograms provide a small dose of radiation, and it’s not yet known whether repeated small doses of radiation further increase the risk of breast cancer in women who’ve already received high doses of radiation to the chest area.

Against the Odds

“Although the majority of women who’ve had chest radiation will never have breast cancer, between 12 and 20 percent will have breast cancer by age 45,” says Kevin Oeffinger, MD, director of the program for adult survivors of pediatric cancer at Memorial Sloan-Kettering Cancer Center in New York City.

In an effort to evaluate screening practices among female survivors of pediatric cancer, Oeffinger and colleagues analyzed data from a group of 625 women who had survived childhood cancer and had undergone chest radiation as part of their treatment.

“When we looked at how frequently these women were having breast cancer screening, we found that only 37 percent of women age 25 to 39 had been screened in the last two years,” says Oeffinger. “In women between 40 and 50, about 77 percent had been screened in the last two years, but most were not in a regular pattern of screening.”

He adds, “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.”

The risk of developing breast cancer can begin as soon as eight years after radiation treatment ends. Women who have survived Hodgkin’s lymphoma through treatment with high-dose radiation present the highest risk for breast cancer in this demographic – escalating them to a risk level comparable to women with BRCA mutations. Because of this, experts are advising these women to have yearly mammograms starting at age 25, or eight years after completing chest radiation therapy, whichever comes later.

Raising awareness of the guidelines could also make a significant difference in this particular demographic, as far as early screening for breast cancer is concerned. For example, the study found that if a doctor recommended screening for those women at high risk – especially for those aged 25 to 39 – they were three times more likely to have a mammogram than women whose doctors didn’t suggest it.

However, not many doctors are aware of their patient’s former diagnosis because it is not included in the patient’s medical history when these women transfer to an adult physician. Also, because it is a relatively small group of people – about 20,000 to 25,000 women in the United States – most doctors will only have one patient who has both survived a childhood cancer and had chest radiation, so is not a condition they may be familiar with.

Freya Schnabel, MD, director of breast surgery at the New York University Cancer Institute in New York City, advises that when women transition to an adult practitioner, they should inform them of their pediatric diagnosis and the details of their treatment. Also, they should be aware that having this radiation puts them at an increased risk of breast cancer, and if they have any family history of breast cancer, it’s even more important to get screened.

A Database Approach

A second investigation was launched in 2009 by researchers at St. Jude Children’s Research Hospital in Memphis, Tenn. after a survey of 551 women – ages 25 to 50 – who had been treated for childhood cancers with chest radiation found that little more than half of the women underwent a screening mammogram in the past two years.

“These statistics document a serious problem that a large proportion of women who should be screened at a very young age are not being tested," says Les Robison, PhD, chair of the Epidemiology and Cancer Control department at St. Jude.

Each of the women was a participant in the Childhood Cancer Survivor Study (CCSS), a multi-institutional study funded by the National Cancer Institute, for individuals who survived five or more years after treatment for cancer, leukemia, or tumor diagnosed during childhood or adolescence. CCSS was created to monitor the long-term effects of cancer and therapy, in order to help design treatment protocols and intervention strategies that would increase survival and minimize harmful health effects on current pediatric patients.

In addition, CCSS also works to educate cancer survivors about the potential impacts of cancer diagnosis and treatment on their health, as well as provide follow-up care – namely by creating and implementing programs for the prevention and early detection of late effects.

The CCSS is a component of the Long-Term Follow-Up Study, which includes a cohort of 20,346 childhood cancer survivors diagnosed between 1970 and 1986. The Study also includes approximately 4,000 siblings of survivors who serve as a relative high-risk comparison group.

As noted in earlier research, physician recommendations were most likely to influence the women to have mammograms – the women who had a positive view of screening mammography were also more likely to have mammograms.

With this in mind, Robison says that, aside from continuing to monitor the mammogram frequency among the at-risk women, the CCSS consortium will develop educational programs for these women and healthcare providers. “We would hope that these programs could achieve the ultimate goal of bringing the screening rate of this at-risk population to 100 percent,” he says.

To further this effort, St. Jude’s After Completion of Therapy Clinic follows patients who have been in remission for five years and  evaluate them yearly until age 18 or 10 years after diagnosis – whichever comes later. In one of the most significant undertakings in survivorship research, the St. Jude Life study is inviting more than 4,000 of its childhood cancer survivors – many who are in their fourth, fifth, and sixth decades of life – to return to the hospital for evaluation.

Efforts such as these are spreading throughout a network of cancer centers focused on improving the quality of life of adults who have received radiation treatment for pediatric cancer. While researchers from multiple hospitals are currently pursuing areas of study to understand what other effects childhood cancer treatments may have on this population, the choice – and the opportunity for early cancer detection – still remains in the hands of today’s cancer survivors.

– Bob Stott is the consulting editor for rt image. Questions and comments can be directed to editorial@rt-image.com.