Young women who develop breast cancer during their pregnancy, or who are diagnosed within one year of their pregnancy, have no difference in rates of local recurrence, distant metastases and overall survival compared to other young women with the disease, according to researchers at The University of Texas M. D. Anderson Cancer Center.

However, the largest single-institution study to look at pregnant breast cancer patients finds that women with Pregnancy Associated Breast Cancer (PABC) are more likely to be diagnosed later with advanced stages of the disease and, thus, have necessary treatment delayed.

The findings are published in the March 15 issue of the journal Cancer.

"Breast cancer in young women is a highly aggressive disease, and it's 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 first 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."

It's estimated that up to 3.8 percent of pregnancies are complicated by breast cancer, and approximately 10 percent of breast cancer patients under age 40 develop the disease during pregnancy, said the researchers. As the age for first and subsequent pregnancies increases and intersects with advances in imaging and screening, this statistic will only continue to climb, explained 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, the study's senior author.

For the retrospective study, Beadle, Perkins and their colleagues reviewed the records of 652 M. D. Anderson breast cancer patients, all were 35-years-old or younger at the time of diagnosis and treated at M. D. Anderson between 1973 and 2006. Of those women, 104 (15.6 percent) had PABC - 51 developed their cancer during their pregnancy and 53 developed the disease within one year post-pregnancy. Median follow-up for PABC patients compared to non-PABC patients was 95.5 months versus 91 months respectively.

When comparing the PABC and the non-PABC cohorts, the researchers found no statistical difference between the 10-year rates of: locoregional recurrence (23.4 percent, PABC; 19.2 percent, non-PABC), metastasis (45.1, percent PABC; 38.9 percent, non-PABC), or overall survival (64.6 percent, PABC; 64.8 percent, non-PABC).

"What we did find, however, is that women with PABC presented with more advanced disease, both in the breast and lymph nodes," said 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."

In an analysis of the 51 PABC patients who developed breast cancer during their pregnancy, 26 received some form of treatment; 25 received no therapy. Of those 25, 22 patients (88 percent) had disease symptoms that were not evaluated; three had a breast cancer diagnosis but were advised not to begin treatment until after delivery.

In PABC patients, the overall survival in those who received therapy was 78.7 percent, compared to 44.7 percent in those who receive none, though researchers caution that these statistics reflect a small sample size. Regardless, the researchers say it's important to note that there was no difference in the statistic by decade, reiterating there's still progress to be made in terms of diagnosing and treating the disease during pregnancy.

"Women really need to be aware of changes to their breasts that persist, even during pregnancy and to discuss these changes immediately with their doctor," said Perkins. "The study also proves that there's a vital opportunity for physicians to focus on complete breast care during a patient's pregnancy, and should include cancer as a possible diagnosis. Persistent complaints should be monitored aggressively, with breast exams, imaging and biopsy, all being conducted as necessary."

In addition to Beadle, Perkins and Theriault, other authors on the all-M. D. Anderson study include: Thomas Buchholz, M.D., Eric Strom, M.D., Wendy A Woodward, M.D., Ph.D., Welela Tereffe, M.D., all in the Department of Radiation Oncology; Jennifer K. Litton, M.D., Department of Breast Medical Oncology; Funda Meric-Bernstam, M.D., Department of Surgery; and Lavinia P. Middleton, M.D., Department of Pathology.