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Breast Cancer During Pregnancy
Abstract & Commentary
By William B. Ershler, MD
Synopsis: Of 688 breast cancers occurring in 652 women 35 years and younger, 15.6% were associated with pregnancy (either during pregnancy or during the subsequent year). Although the tumors occurring in association with pregnancy were larger, there was no significant difference in local recurrence, distant metastases, or overall survival. There was a trend toward reduced overall survival among those pregnant women who delayed primary breast cancer therapy until after delivery.
Source: Beadle BM, et al. The impact of pregnancy on breast cancer outcomes in women < 35 years. Cancer. 2009;115:1174-1184.
Approximately 10% of breast cancers that occur in woman younger than age 40 is associated with pregnancy,1 and there is some evidence to suggest that pregnancy-associated breast cancers (PABC) are particularly aggressive.2-4 However, others have found that breast cancer is more likely to present at a more advanced stage when associated with pregnancy, and that when matched for stage, prognosis is similar for patients with PABC when compared to similarly aged breast cancer patients.
To address this issue, Beadle et al from the University of Texas M.D. Anderson Cancer Center performed a retrospective analysis of patients treated at their Center to compare locoregional recurrence (LRR), distant metastases (DM), and overall survival (OS) in young patients with PABC and non-PABC.
For this, data on 668 breast cancers in 652 patients aged < 35 years treated from 1973 to 2006 were reviewed. Of these, 104 breast cancers (15.6%) were pregnancy-associated, 51 cancers developed during pregnancy, and 53 within one year after pregnancy. The median follow-up for all patients was 91 months (range 2-411 months). Comparing the groups (PABC or non-PABC), there were no differences in age, race, family history, decade of treatment, histology, or nuclear grade. However, patients who developed PABC had more advanced T classification, N classification, and stage group (all p < .04) compared with patients with non-PABC. Nonetheless, patients with PABC had no statistically significant differences in 10-year rates of LRR (23.4% vs. 19.2%), DM (45.1% vs. 38.9%) or OS (64.6% vs. 64.8%) compared with patients with non-PABC.
Among the patients who developed cancer during pregnancy, approximately one half underwent some form of treatment, and there was a trend towards improved overall survival for that group compared to those who had elected to delay therapy (78.7% vs. 44.7%; p = 0.068).
It is a commonly held notion that breast cancer, when it occurs in young women, is particularly aggressive, and there are substantial data that support that contention.5 Although pregnancy is associated with approximately 10% of breast cancers in young women, the data from this series, and from others3,4,6 would seem to indicate that the pregnant state does not a priori confer a negative influence. The extensive experience at M.D. Anderson has, with this report, demonstrated that young patients with PABC had no statistically significant differences in local recurrence, distant metastases, or overall survival compared with those with non-PABC. However, pregnancy contributed to a delay in breast cancer diagnosis, evaluation, and treatment and, thus, patients, at the time of diagnosis, are found to have more advanced disease. Current preliminary observations from a clinical trial conducted at their institution mentioned, only briefly in this article, suggest that chemotherapy can be safely and effectively administered to pregnant women. If these preliminary findings are substantiated, it would represent a significant advance, as earlier treatment of breast cancer in the pregnant patient would likely result in a greater chance of increasing response rates and survival. Accordingly, primary care and reproductive physicians should be aggressive in the work-up of breast symptoms in the pregnant population to arrive at a diagnosis and allow an earlier introduction of effective therapy.
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2. Bonnier P, et al. Influence of pregnancy on the outcome of breast cancer: a case-control study. Societe Francaise de Senologie et de Pathologie Mammaire Study Group. Int J Cancer. 1997;72:720-727.
3. Zemlickis D, et al. Maternal and fetal outcome after breast cancer in pregnancy. Am J Obstet Gynecol. 1992;166:781-787.
4. Petrek JA, et al. Prognosis of pregnancy-associated breast cancer. Cancer. 1991;67:869-872.
5. Axelrod D, et al. Breast cancer in young women. J Am Coll Surg. 2008;206:1193-1203.
6. Ezzat A, et al. Impact of pregnancy on non-metastatic breast cancer: a case control study. Clin Oncol (R Coll Radiol). 1996;8:367-370.