Pregnancy-associated Breast Cancer and Increased Risk of Pregnancy-associated Recurrence

A Case Report

Freya Schnabel; Jessica Billig; Arielle Cimeno; Jennifer Chun

Disclosures

J Med Case Reports. 2012;6(144) 

In This Article

Abstract and Introduction

Abstract

Introduction Pregnancy-associated breast cancer refers to breast cancer diagnosed during pregnancy, lactation, or within twelve months postpartum. Recent studies suggest that, when matched for age and stage, the prognosis of pregnancy-associated breast cancer is comparable to non-pregnancy-associated breast cancer. However, the risk for breast cancer recurrence associated with subsequent pregnancies in this population is not clear.
Case presentation We describe the case of a Caucasian woman who was initially treated for pregnancy-associated breast cancer at age 23, three months after the birth of her third child. She underwent a total mastectomy with axillary node dissection, followed by chemotherapy and hormonal therapy. Ten years later, when the patient was 24 weeks pregnant with her fourth child, she presented with an ipsilateral chest wall recurrence of breast cancer. To the best of our knowledge, this represents the first reported case of a pregnancy-associated recurrence in a patient previously treated for pregnancy-associated breast cancer.
Conclusion The case described here is the first report of a second occurrence of pregnancy-associated breast cancer. This case raises the possibility that pregnancy may represent a unique trigger for breast malignancy in a specific cohort of women. Although there is data showing no increase in the risk of recurrence for women who become pregnant after breast cancer treatment, pregnancy-associated breast cancer may be a distinct clinical category where subsequent pregnancies after treatment may confer an increased risk of recurrent disease.

Introduction

In 10 % of women diagnosed with breast cancer (BC) under the age of 40 years, the disease is associated with pregnancy.[1] BC is diagnosed in approximately one in 3,000 pregnancies, making it the second most common pregnancy-associated malignancy (after cervical cancer).[2] With more women delaying childbearing, researchers predict that the prevalence of pregnancy-associated breast cancer (PABC) will continue to rise.[2] Even though increasing parity is protective against BC, women at any age are at a greater risk of developing the disease within two years postpartum.[3] The increased incidence of BC following childbirth suggests that pregnancy may stimulate the growth of cells that have already undergone malignant transformation.[3–5] While the exact mechanisms for this phenomenon are unknown, estrogen and progesterone are established mitogens for breast tissue[5,6] Several theories have been postulated about the effect of the unique hormonal milieu of pregnancy in promoting the expansion of malignant cells[5,6]

Historically, it was assumed that PABC carried a worse prognosis than BC.[7] PABC usually presents at a more advanced stage, with larger primaries and more lymph node involvement[2,8] This may be due to the difficulty of detecting BC via physical examination, mammography and ultrasound in pregnant and lactating women.[1] In general, mammography in women of reproductive age usually reveals dense parenchyma, decreasing the sensitivity of the exam. It has now been shown that, when matched for age and stage, the prognosis for PABC and BC is comparable. Once detected, the histology of PABC is similar to cancer in non-pregnant women.[1] Although there is a higher frequency of lymphovascular invasion and high nuclear grade in PABC, these features are frequently found in patients under 40 years and are thought to be more correlated with age than pregnancy.[1] The current management of PABC closely follows the protocols in place for similarly staged BC, and PABC diagnosed after delivery is treated as typical BC.[9]

With women delaying childbirth, there is a larger group of premenopausal survivors of BC interested in subsequent childbearing.[10] In the past, women were discouraged from childbearing after BC diagnosis; yet, contemporary research establishes that pregnancy after breast cancer does not imply a worse prognosis. From retrospective trials, pregnancy after BC does not increase risk of recurrence,[10] and there is no significant difference in the survival of women who have children after breast cancer treatment and those who do not.[4] Pregnancy after BC treatment implies no further risk, and therefore more breast cancer survivors are choosing to become pregnant.

In the following case, a patient who had been treated for PABC developed another episode of PABC during a subsequent pregnancy ten years after her initial diagnosis. Our case, coupled with the current theories regarding pregnancy and breast malignancy, strongly suggests that women with PABC may represent a specific subgroup of women for whom a subsequent pregnancy may impart unique risks. This observation supports the need to consider a prior history of PABC when counseling BC survivors concerning the potential risks of future pregnancies.

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