Pregnancy Does Not Affect Breast Cancer

By Margarita Nahapetyan

A new study conducted at The University of Texas finds that young women who develop breast cancer during pregnancy, or who are diagnosed soon afterwards, do not have any differences in disease severity or overall survival, compared to other young women with breast cancer.

The researchers also noted that it is very difficult to diagnose breast cancer during pregnancy, which leads to delays in necessary early treatment for affected patients. By the time breast cancer is revealed, women find themselves already in advanced stages of the disease.

"Breast cancer in young women is a highly aggressive disease, and it is important that we study it in hopes of making a difference in terms of treatment," said Beth Beadle, M.D., a radiation oncology resident at M. D. Anderson, and the study's lead author. "When we looked at our young breast cancer population, a relatively large percentage had disease affiliated with pregnancy. We thought it would be really instructive to review our data to determine how we can best serve these women."

The scientists noted that nearly 4 per cent of pregnancies develop breast cancer, and about 10 per cent of young breast cancer patients under the age of 40 develop the disease while being pregnant. As the age for the first and following pregnancies eventually increases and intersects with imaging and screening advances, this statistics will only continue to grow, explained the study's senior author George Perkins, M.D., associate professor in M. D. Anderson's Department of Radiation Oncology.

"Because we see care for large volume of patients who are young, as well as those who are young and pregnant, we wanted to see if there was something additive going on that is attributed to pregnancy, or if the response to treatment and behavior of the disease is a phenomenon of young age itself," said Perkins.

For their study, the researchers examined the records of 652 University of Texas M. D. Anderson Cancer Center patients with the disease, aged 35 years or younger at the time of diagnosis, and treated at M. D. Anderson between 1973 and 2006. They found that from all women one hundred and four (15.6 per cent) had PABC (pregnancy-associated breast cancer), 51 women developed their cancer during their pregnancy and 53 developed the disease within a year of pregnancy. The researchers found no difference in a 10-year survival rates when compared to other women who develop breast cancer. Treatment and therapy during pregnancy provided the best results.

"What we did find, however, is that women with PABC presented with more advanced disease, both in the breast and lymph nodes," said Beth Beadle. "These women seem to have a significant delay in diagnosis, and their symptoms were not identified as breast cancer for an extended period of time - putting them at a disadvantage by withholding necessary treatment."

The analysis of the fifty one PABC patients who developed the disease while being pregnant, showed that twenty six women received some form of treatment, and twenty five received no therapy at all. Among all the patients 88 per cent had disease symptoms that were not evaluated, 3 were diagnosed with breast cancer but were advised not to start any treatment until after labor.

In women with PABC, the overall survival in those who underwent therapy was about 79 per cent, compared to almost 45 per cent in those patients who did not receive any treatment. Though researchers noted that pregnancy often causes a delay in diagnosing as well as treating breast cancer, they found that women improved their chances of survival by receiving treatment during pregnancy rather than waiting until after giving birth.

The main difference in treatment, Perkins said, was that pregnant women should not undergo chemotherapy during the first three months of their pregnancy, as this is the particular time when the baby's organs are being formed and they are extremely vulnerable. But according to past studies, when chemo begins in the second or third trimester of pregnancy, the babies that are born are as healthy as babies born to cancer free mothers, and the women themselves have as good chance of survival as all other women with the disease.

"Primary care and reproductive physicians should be aggressive in the work-up of breast symptoms in the pregnant population to expedite diagnosis and allow multidisciplinary treatment," the authors wrote in their report. "Balancing the health of mother and child is paramount; new evidence suggests that both can be prioritized and successful outcomes managed for both."

The study is published in the March 15, 2009 issue of CANCER, a peer-reviewed journal of the American Cancer Society.