Breast cancer (BC) is the most common type of cancer diagnosed in young patients: every year approximately 3-4% of BC are diagnosed in patients younger than 40 years. The proportion of patients with at least one full-term pregnancy after BC diagnosis is very low: only 3% of women younger than 45 years at diagnosis (8% if considering only women aged less then 35 years ) . Potential explanations for this finding are fertility damage derived from gonadotoxic therapy and fears of a negative impact of pregnancy on the evolution of BC. There are two main concerns faced by both patients and their physicians in experiencing pregnancy after cancer diagnosis and treatment, especially for women with previous endocrine-sensitive BC:
- the potential obstetric and fetal adverse effects of previous cancer treatments. Available data do not suggest an increased risk of birth defects or genetic diseases in infants delivered by patients previously treated with anticancer therapies [2,3]. But an increased incidence of birth complications (caesarean section, preterm birth, babies with low birth weight) in treated women as compared to controls is reported . Therefore, a close monitoring of pregnancy in women previously treated for cancer is recommended;
- the possibility that the pregnancy might have negative consequences on the prognosis of the patient herself: in the past, on the basis of purely theoretical assumptions, there were concerns about a possible negative impact of a subsequent pregnancy, particularly in patients with history of endocrine-sensitive BC. Available clinical data do not confirm such hypothesis. A meta-analysis of 14 retrospective control-matched studies that had assessed the impact of pregnancies on overall survival (OS) of women who experienced BC, showed a potential protective effect of pregnancy itself on patients prognosis. However the “healthy mother effect” could not be ruled out .
To better clarify the impact of pregnancy on disease-free survival (DFS) in women with history of BC according to estrogen receptor (ER) status, Azim et al. performed a retrospective cohort study that has been recently published in the Journal of Clinical Oncology. Patients who became pregnant any time after BC were matched (1:3) to patients with BC who did not become subsequently pregnant with similar ER, nodal status, adjuvant therapy, age and year at diagnosis. The primary objective of the study was DFS specifically in patients with ER-positive disease; secondary objectives were DFS in the ER-negative population, whole population and OS. A total of 333 pregnant BC patients and 874 matched nonpregnant patients were included in the study; 58% of pregnant patients and 56% of nonpregnat patients had ER positive disease. Median follow up from time of conceptions was 4.7 years; in the pregnant group the median time from BC diagnosis to conception was 2.4 years. Overall, 354 patients (29.3%) experienced a DFS event, with no differences in event rates observed between the ER-positive and ER-negative cohorts. The hazard ratio [HR] of 0.91 (95% confidence interval [CI], 0.67-1.24; p=.55) observed in patients with ER-positive BC indicates that women who became pregnant after BC were not at higher risk of developing recurrence compared to nonpregnant women. Similarly, there was not an increased risk of recurrence when all patients were considered regardless of ER status (HR: 0.84), or when considering the ER-negative cohort (HR: 0.75). The pregnant group showed a better OS (HR: 0.72; 95% CI, 0.54-0.97; p=.03) with no interaction observed according to ER status, but OS was a secondary objective.
In conclusion, pregnancy does not affect prognosis of patients after BC diagnosis and treatment and could be considered safe even in women with history of endocrine-sensitive BC.
- What is your feel toward a patient with a previous history of endocrine-sensitive BC who wants to become pregnant?
- How long do you recommend patients to wait between the end of anticancer treatments and the conception?
- What is your advice towards a patient who wants to become pregnant after 2 years of endocrine therapy before the completion of the established 5 years?
- Del Mastro L, Catzeddu T, Venturini M. Infertility and pregnancy after breast cancer: current knowledge and future perspectives. Cancer Treat Rev 2006; 32:417-422.
- Langagergaard V, Gislum M, Skriver MV, et al. Birth outcome in women with breast cancer. Br J Cancer 2006; 94:142-146.
- Winther JF, Olsen JH, Wu H, et al. Genetic disease in the children of Danish survivors of childhood and adolescent cancer. J Clin Oncol 2012; 30(1):27-33.
- Dalberg K, Eriksson J, Holmberg L. Birth outcome in women with previously treated breast cancer-a population –based cohort study from Sweden. PLoS Med 2006; 3(9):e336.
- Azim HA Jr, Santoro L, Pavlidis N, et al. Safety of pregnancy following breast cancer diagnosis: a meta-analysis of 14 studies. Eur J Cancer 2011; 47:74-83.
The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society for Medical Oncology.