Time to subsequent pregnancy (months)
Beta coefficient
P value
Hazard ratio (95 % CI)
<6
0.79
0.579
2.20 (0.14–35.42)
6–24
−0.80
0.135
0.45 (0.16–1.28)
>24
−0.74
0.009
0.48 (0.27–0.83)
The optimal timing of pregnancy after breast cancer is still undefined and the decision depends on patient’s prognosis, age and personal condition. Because of the reassuring studies on patients who get pregnant 2 years and more after breast cancer and the observation that recurrences occur more frequently in the first few years, a delay of 2–3 years is conventionally recommended.
This time interval would also allow to recover from chemotherapy-induced ovarian toxicity. Women with ER-negative breast cancer should be advised to wait at least 6 months from the end of treatments before conceiving, to avoid the possible toxic effect of chemotherapy on growing oocytes.
As to ER-positive breast cancer, current guidelines recommend at least 5 years of endocrine therapy [26]. Furthermore, recent evidence suggests that 10 years of tamoxifen confer even greater protection [27]. Because of the teratogenetic effects of tamoxifen, pregnancy during endocrine therapy is contraindicated and an off-therapy period of 3–6 months is recommended before conceiving. But the reproductive potential is declining year by year, because of the physiological loss of ovarian reserve and the harms of chemotherapy. The feasibility of a temporary break of the hormonal therapy allowing to conceive and have a full-term pregnancy, with subsequent completion of endocrine treatment is under investigation. A prospective study of the Breast International Group and North American Breast Cancer Group (BIG-NABCG) is currently ongoing, investigating the clinical and biological features contributing to a safe and successful pregnancy in ER-positive breast cancer patients. The analysis will focus on both oncological outcomes (local and distant recurrences and survival) and obstetrical outcomes (spontaneous abortion, preterm delivery, intrauterine growth restriction, low weight at birth, fetal malformations). Secondary endpoints of the study are the feasibility and the impact of a temporary break of endocrine therapy to allow conception and the optimal duration of subsequent hormonal therapy after delivery and breastfeeding [28].
6.4 Obstetrical and Neonatal Outcome
One of the unnamed concerns that patients face is the fear of a potential teratogenic effect of antineoplastic treatments on the offspring. Few data are available on birth outcomes in breast cancer survival; however, no excess risk for the newborn health is suggested [28].
Some studies found a higher rate of abortion than in general population. This information may be biased because most of the studies did not discriminate between spontaneous and induced abortion. When this issue was considered, the risk of spontaneous abortion did not seem to be higher in breast cancer patients than in general population. On the contrary, the rate of induced abortion is consistently higher, suggesting that uncertainties of patients and physicians about safety of pregnancy after breast cancer often lead to dramatic choices [29]. Studies comparing disease-free survival in patients who completed their pregnancy to term and patients who had an abortion found a not statistically significant trend towards better outcome in women who had a full-term pregnancy [23].
Two large studies assessed the obstetrical and neonatal outcomes of pregnancies following breast cancer. A Danish nationwide cohort study investigated whether maternal breast cancer affects birth outcome [30]. Data about pregnancies of 216 women with a history of breast cancer were matched with a comparison cohort of 10,453 women belonging to general population. Similar rates of low birth weight, stillbirth and congenital abnormalities were observed in the two groups. A small and not statistically significant higher preterm delivery rate was observed in the breast cancer cohort. Mean birth weight was nearly 3,400 g in both groups, as well as mean gestational age at delivery. Different findings were reported in a Swedish cohort study aiming to assess delivery risk and neonatal health [31]. Data were extrapolated from the Swedish Medical Birth Registry and the Swedish Cancer Registry, including 331 mothers with a history of breast cancer and 2,870,518 mothers belonging to general population. An increased risk of delivery complication, caesarean section, preterm delivery and congenital malformations and no difference in low birth weight rate at delivery was observed. Authors conclusion is that pregnancy after breast cancer should be considered at high risk and therefore managed and surveilled accordingly.
Usually women with previous breast cancer are more likely to give birth at an older age than the general population. Both studies point out this difference in maternal age. About 50 % of women in breast cancer cohort are 35 years old or more at delivery, with a mean age of 34 years, whereas in the comparison group the figures are 11 % and 28 years, respectively [30, 31]. It is well known that pregnancy at an old age is more susceptible to many comorbidities and complications as gestational hypertension, preeclampsia, gestational diabetes and other conditions that bring about high risk for pregnancy outcome and require special surveillance. This may partially explain the slightly higher rate of pregnancy complications reported in the Swedish study, but uncertainties still exists.
6.5 Breastfeeding After Breast Cancer
Many factors, such as personal, cultural, social and environmental factors, influence women’s decision about breastfeeding. Beyond these, breast cancer survivors face unique physical and emotional factors that might impact their decision and ability to breastfeed.
A qualitative research explored by an interview the experience and the feelings about breastfeeding in a selected group of breast cancer survivors [32]. Generally, patients alleged the wish to breastfeed, but also anxiety and concerns about doing it. This highlights the need of prenatal education and information to prepare the prospective mother to the challenges of breastfeeding. Breast cancer survivors alleged physical and emotional problems, mainly because they had to rely primarily or entirely on one breast. Treatments for breast cancer can affect lactation. Proximity of the surgical incision to the nipple-areola complex, dose and type of radiation therapy may reduce or inhibit lactation. Thus, many patients can breastfeed from the untreated breast only, with consequent uncertainty about whether or not the milk supply would be sufficient for the infant [32]. Failure to nurse from one breast should not affect the use of the other and the mother should be reassured about the adequacy of milk production by a single breast, sufficient for the nutritional need of the newborn.
Another survey analysis was performed investigating the breastfeeding patterns and habits in breast cancer survivors [33]. Hypoplasia and hypotrophia of the operated and irradiated breast were observed, with consequent reduced milk production, nipple pain, physical changes and discomfort during latching. Furthermore, a previous mastectomy was associated with short-lasting breastfeeding. This is not only justified by the fact that these patients have a single breast to nurse their babies, but also women with previous breast conserving surgery used one breast only for lactation. A possible alternative explanation is that body image plays an important role in the success of breastfeeding, and breast-conserving surgery, in spite of mastectomy, may reinforce the feeling of maternal adequacy. A proper breastfeeding counselling is a key factor for successful and prolonged breastfeeding in breast cancer survivors. This experience often brings about a psychological rehabilitation and patients express satisfaction to have been able to breastfed their babies, even if it required efforts and sometimes milk supplement.
These results enlighten the reasons of breast cancer survivors to breastfeed and the challenges which they will face and concern them. It is of the utmost importance that physicians provide practical and continuous support to the mother, especially during the postpartum period.
Beyond feasibility the safety of breastfeeding after breast cancer treatment remains an open question. Several studies have demonstrated the protective effect of breastfeeding on breast cancer risk in general population. A meta-analysis including data from 47 epidemiological studies, evaluating the relationship between breastfeeding and breast cancer, has demonstrated a 4.3 % reduction of the relative risk of breast cancer for each year that a woman breastfeeds [34]. In order to reduce biases, stratifications for age, parity, ethnicity and age at first delivery were performed, matching women who breastfed and who did not breastfeed on the basis of the same characteristics. The conclusion was that the benefits are statistically significant and breastfeeding should be encouraged.
While there is evidence that breastfeeding reduces breast cancer incidence in general population, there are no solid epidemiological data about breastfeeding after breast cancer. A retrospective case-control study investigated the survival rate of patients treated for breast cancer who subsequently became pregnant [35]. A recent re-analysis of those data was performed, specifically focused on the role of breastfeeding. A better survival was suggested in women who breastfed. These data could be biased, but it may be supposed that breastfeeding does not have a detrimental effect on breast cancer outcome [36].
The mechanisms underneath the association of breastfeeding and reduction of breast cancer incidence are not known. Several hypotheses were expressed in various studies and were synthesised in a review article [36]. Some data suggest that lactation may reduce the carcinogens level in the breast. Another hypothesis is the suckling-related blockage of the hypothalamus-pituitary axis leading to lactational amenorrhoea. From animal models, it was hypothesised that differentiation of the mammary gland as observed during pregnancy and lactation protects from neoplastic evolution. The role of prolactine has been widely studied but with conflicting results, and the impact of this hormone on initiation and promotion of breast cancer in humans remains unclear.
Epithelium changes and stromal activation which occur in remodelling breast tissue may be associated with a temporary increase in breast cancer incidence. This observation recommends a thorough follow-up of women with history of breast cancer after pregnancy or lactation. Patients and physicians often tell of the fear of a delay in diagnosis in case of tumour recurrence. Lactation does not interfere with clinical and radiological evaluation of the breasts. Ultrasound exam can be safely performed and in case of suspicion, mammography or breast magnetic resonance imaging can be performed after having drained the lactating breasts [36].
Despite uncertainty, the benefits of breastfeeding to the baby and the mother are well established. Newborns who are breastfed are protected from infections in the short period and are less susceptible to develop autoimmune diseases and metabolic disorders at adult age. Furthermore, a benefit in neurocognitive development of the baby breastfed has been suggested. Breastfeeding bears several advantages for the mother as well. Women who breastfeed have better control of postpartum bleeding, return swiftly at the usual weight and are heavily gratified by the emotional bond which is created with her baby.
In conclusion, current evidence suggests that breast cancer survivors who wish to breastfeed, should be encouraged and supported in their efforts.
6.6 Childbearing Attitudes of Young Breast Cancer Survivors
Many studies have shown that pregnancy and parenthood are two important issues for young women with breast cancer. As breast cancer-related mortality declines, the impact of anticancer treatments on reproductive potential is getting more relevant, and fertility impairment may worsen the quality of life in a growing number of patients. For some young breast cancer survivors, the threat to their childbearing plans has major emotional and psychological consequences. Literature and clinical practice demonstrate that some women remain fertile and have a spontaneous pregnancy after a history of cancer. Additionally, the advent of advanced assisted reproductive technology within the oncology field has made fertility preservation an option for women, prior to the initiation of treatments. As known, other options are available for infertile women, such as adoption and third-party reproduction, but most couples crave biological offspring.
Several studies showed that the risk of early menopause and infertility are causes of concern for about the half of young women who receive breast cancer diagnosis. Some patients reported that this fear conditioned treatment decisions [37]. Infertility in cancer patients is associated, more frequently than in general population, to anxiety, depressive symptoms and sexual impairment which have a negative impact on the quality of life.
But even when fertility is preserved, other concerns upset breast cancer patients. Women fear that the child might be born with a birth defect because of the chemotherapeutic agents they received. They are anxious about a shorter life expectancy and are afraid of having not enough energies to raise children. Furthermore, women feared that the offspring would have a greater susceptibility to cancer [38].
On the other hand, some patients perceive the benefits that could be achieved by having children after breast cancer treatment. Raising a child can be a powerful motivator to stay alive and healthy, it may strengthen the relationship with the partner, it brings back normalcy in their life and it would restore the sense of femininity and sexuality [39]. Breast cancer survivors who are disease-free often feel healthy enough to consider a pregnancy. This is called a reasonable wellness, which may express the ethical guide into the difficult choice of getting mother.
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