March 26th, 2010 
Women who survive breast cancer and have children afterwards don’t appear to be at any higher risk of dying from cancer, a new study says.
Doctors have long worried pregnancy might spark hormonal changes in breast cancer survivors that could spur the disease’s return, and many breast cancer patients are counseled against getting pregnant after they recover.
In research presented Friday at a European breast cancer conference in Barcelona, experts said pregnancy in women who have been treated for breast cancer is safe and does not seem to be linked with the disease’s recurrence.
Among women in the general population, those who have early and multiple pregnancies have a lower risk of getting breast cancer than women who don’t.
Dr. Hatem Azim of the Institute Jules Bordet in Belgium and colleagues analyzed results from 14 previous trials that followed more than 1,400 pregnant women with a history of breast cancer. Those women became pregnant several months to several years after finishing treatment. Azim and colleagues compared those women to more than 18,000 women who had had breast cancer and were not pregnant.
Azim and colleagues found that the women who got pregnant had a 42 percent lower risk of dying compared with breast cancer survivors who did not get pregnant. He said part of that benefit might be due to the fact that women who were naturally healthier were those that later had children.
But in some studies, women with breast cancer who became pregnant were compared to women who remained free of the disease, i.e. the healthiest of the breast cancer survivors.
“For many years, pregnancy was considered a risk for women who had breast cancer,” said Maria Leadbeater, a cancer expert at Breast Cancer Care, a British charity. “But this study seems to show the risk is not an issue once you’ve been treated,” she said. Leadbeater was not connected to Azim’s study.
Leadbeater said the advice for patients might vary depending on the type of breast cancer they’ve had and how they responded to treatment. Women who need hormone therapy for breast cancer typically need to be on it for five years — during which time doctors recommend against getting pregnant.
Leadbeater and others said women should try to wait until two years after their diagnosis to try for a baby, since that is thought to be the riskiest time for a relapse.
Azim, who led the study, hypothesized that the relationship between hormones and breast cancer might be more complicated than doctors initially thought. Estrogen is known to trigger breast cancer and women typically have more estrogen when they’re pregnant. But very high doses of the hormone can also kill cancer cells, Azim said.
Other hormones that are elevated in pregnancy, like the one for breast-feeding, have been proven to protect against breast cancer. “What we are seeing is only the tip of the iceberg,” Azim said. “It’s too simple to say that pregnancy stimulates hormones and that’s bad for breast cancer.”
Related
- Pregnant women with breast cancer face good odds of recovery
Pregnant women who develop breast cancer do not have worse odds of death or of cancer returning than other young breast cancer patients, a recent study has found.
The study is one of the largest to look at whether breast cancer hits pregnant and recently pregnant women harder than other women. It contradicts some smaller, earlier studies that suggested maternity made things worse.
“If we can get them early, we can treat them aggressively and have good and promising outcomes for both woman and child,” said the study’s lead author, Dr. Beth Beadle of the University of Texas M.D. Anderson Cancer Center.
Frightening for any woman, a breast cancer diagnosis is particularly terrifying for a pregnant woman. It presents complicated decisions about how to treat the mother and not harm the fetus. Some doctors recommend abortion so they can focus on treating the mother.
In the new study, published earlier this year in the journal Cancer, researchers analyzed data from 652 women ages 35 and younger who were treated for breast cancer at M.D. Anderson from 1973 through 2006.
The study group included 104 women with pregnancy-associated cancers —- 51 who had breast cancer during pregnancy, and 53 who developed the illness within a year after.
The rates of cancer recurrence, cancer spread and survival were about the same for the women with pregnancy-associated breast cancers as they were for the other women, the researchers found. The researchers calculated the rates for 10 years after the cancer diagnosis.
The women who were pregnant had tumors at a more advanced stage, probably because women and their doctors may have discounted breast changes, attributing them to breast feeding or pregnancy, the researchers believe.
Generally, breast cancers are more aggressive in younger women, and survival rates are significantly lower. While age may be a factor, it’s not clear that pregnancy is: There was no evidence in the new study that tumors were faster growing in the pregnant women, said Beadle, a radiation oncologist.
Radiation —- dangerous to a fetus —- is commonly used in mammography and breast cancer treatment. But ultrasound can be used to look for breast tumors instead. And surgery and certain kinds of chemotherapy can treat the cancer without poisoning the womb.
However, it remains a complicated medical situation that can depend on the severity of the cancer and how far into the pregnancy the mother is, said Dr. Ruth O’Regan, an associate professor at Emory University’s Winship Cancer Institute in Atlanta.
- Pregnant women confront rise in cancer cases
The number of women diagnosed with breast cancer during pregnancy or soon after giving birth has more than doubled since the 1960s, and researchers say cases will continue to rise as women have children later in life.
The incidence of pregnancy-associated breast cancer rose from 16 in every 100,000 deliveries to 37.4 per 100,000 deliveries between 1963 and 2002, a study has found.
Breast cancer was under-diagnosed in pregnant and breastfeeding women because they and their doctors assumed breast firmness or lumps were a normal part of childbearing, said the chief executive of the National Breast and Ovarian Cancer Centre, Helen Zorbas.
She urged health professionals to assess all women the same way, regardless of pregnancy. ”While most breast changes won’t be cancer, early detection is vital for improving survival.”
Although pregnancy does not cause breast cancer, hormonal changes can accelerate its growth and tumours in pregnant women are often larger and more advanced by the time they are detected than those in women who are not pregnant.
The disease poses a dilemma for patients and their doctors. Pregnant women can have surgery but not radiotherapy. And chemotherapy is allowed only after the first trimester.
The study, published in the journal Obstetrics & Gynecology, reviewed more than 4.1 million deliveries in Sweden between 1963 and 2002.
The Karolinska Institute in Stockholm found the largest proportion of pregnancy-related breast cancers was among 25- to 29-year-olds.
But because the breast cancer risk rose with age and the average age of mothers had increased to about 30, its incidence during pregnancy was likely to increase, the institute said.
- How Exactly Does Breast Feeding Lower The Risk Of Breast Cancer?
They say it lowers the risk, but how does breast feeding your baby lower the risk of developing breast cancer?
- Exposure to passive smoking during pregnancy ‘increase children’s risk of cancer in later life’
Pregnant women subjected to passive smoking give birth to babies with an increased, lifelong susceptibility to cancer, research reveals.
Passive smoking causes the same type of genetic damage in unborn infants as that found in adult smokers with cancerous tumors.
Researchers said the abnormalities in newborns were indistinguishable from those found in babies of mothers who were active smokers.
And they may affect survival, birth weight and lifelong susceptibility to diseases like cancer, according to the study published online in the Open Paediatric Medicine Journal.
Dr Stephen Grant and colleagues at the University of Pittsburgh in the U.S. found a smoke-induced mutation in an oncogene, a gene which transforms normal cells into cancerous tumors.
The mutation was the same level and type in newborns of mothers who were active smokers as those in babies born to non-smoking mothers exposed to tobacco smoke.
The mutations were also discernible in newborns of women who had stopped smoking during their pregnancies, but who did not actively avoid second-hand smoke.
The study confirms previous research in which Dr Grant discovered evidence of genetic abnormalities in babies whose mothers were exposed to environmental tobacco smoke.
There is also evidence that maternal exposure to passive smoke, as well as a history of paternal cigarette smoke exposure, is linked with an increased risk of childhood cancer, especially leukaemias and lymphomas in children under five.
Dr Grant said: ‘These findings back up our previous conclusion that passive, or secondary, smoke causes permanent genetic damage in newborns that is very similar to the damage caused by active smoking.
‘By using a different laboratory test, we were able to pick up a completely distinct yet equally important type of genetic mutation that is likely to persist throughout a child’s lifetime.
‘Pregnant women should not only stop smoking, but be aware of their exposure to tobacco smoke from other family members, work and social situations.’
- Moms post-birth bleeding tied to early radiation
Women who had radiation to the abdomen in childhood to treat cancer may experience excessive bleeding after giving birth, new study findings suggest.
The study evaluated pregnancy and birth outcomes in 40 women who were 30 years old on average and had been treated when about 7 years old for cancers of the blood, kidney, bone, and other locations.
Twenty-eight of the women were pregnant with their first child, eight with their second, and the rest were on their third, fourth or fifth pregnancies.
In general, these women had outcomes similar to more than 9000 women who never had cancer, Dr. Sharon Lie Fong, at Erasmus Medical Center in Rotterdam, The Netherlands, and her colleagues found.
However, the six women previously treated with abdominal radiation appear to be the exception.
Although just two of the six bled severely after childbirth, percentage-wise this represents a higher rate (33 percent) of severe bleeding cases relative to that seen in the general population where just 5 percent bled after childbirth.
The researchers urge health care providers to be aware of this risk when treating women cancer survivors during pregnancy, particularly since this finding “has not been reported so far in childhood cancer survivors,” Lie Fong’s team notes in the journal Human Reproduction.
Notably, the women’s very young age at cancer treatment — about 7 years old on average — did not seem to prevent harmful effects of radiation to their small, pre-puberty uteruses.
The six women who received radiation to the abdomen in childhood also delivered their babies an average of 4 weeks earlier than their cancer-free peers. However, babies born to the cancer survivors, including those previously treated with abdominal radiation, appeared as healthy as those born to cancer-free moms.
Due to the increased risks noted in this study, Lie Fong’s team discourages home birth and encourages heightened prenatal care for women who received abdominal radiation for childhood cancer.
