A large meta-analysis of breast cancer survivors of childbearing age has shown that they are less likely than the general public to become pregnant and have a increased risk of certain complications, such as premature delivery. However, the majority of those who become pregnant deliver healthy babies and have no adverse effects on their long-term survival, according to data presented at the 2020 San Antonio Breast Cancer Symposium in the United States.
‘With the availability of more effective anticancer treatments, survival has gained substantial attention. Today, the return to a normal life after cancer diagnosis and treatment should be seen as a crucial ambition in cancer care. In patients diagnosed during their reproductive years, this includes the possibility of completing their family planning ”, explains the corresponding study author, Matteo Lambertini, associate professor of medical oncology at the University of Genoa – IRCCS Polyclinic San Martino Hospital in Genoa ( Italy).
As the average age for pregnancy has increased over time, it has become more common for women to be diagnosed with breast cancer before having a child. Furthermore, Lambertini explains that many of cancer therapies that have successfully reduced mortality from breast cancer have possible long-term toxic effects on the body, including potentially harmful fertility and future family planning. For example, adjuvant endocrine therapy that is prescribed for women diagnosed with hormone receptor positive breast cancer is given for five to 10 years after diagnosis and during this treatment, pregnancy is contraindicated.
In this study, the researchers conducted a systematic literature review of 39 studies that identified women who had been pregnant after a breast cancer diagnosis. They evaluated studies to assess the frequency of post-treatment pregnancies in these women, fetal and obstetric outcomes, disease-free survival, and overall survival. Total, collected data on 114,573 patients with breast cancer.
Compared to women in the general population, patients who had had breast cancer had 60 percent less likely to have a pregnancy. Lambertini notes that this study did not specifically collect the total number of women who tried to conceive, so it is possible that some women did not attempt pregnancy after completing treatment.
Some studies included in the analysis reported such data, and Lambertini estimates that more than half of the young women who tried to conceive did so. Also, some women who did not intend to conceive became pregnant. Lambertini highlights that this finding suggests that cancer patients of childbearing age should also receive accurate information about contraception.
No congenital defects
The study has shown that, compared with women in the general population, breast cancer survivors had a 50 percent higher risk of having a low-birth-weight baby; 16 percent increased risk of having a small baby for gestational age; 45 percent increased risk of preterm labor and a 14 percent increased risk of having a C-section.
However, what is more important, there was no significantly increased risk of birth defects or other complications of pregnancy or childbirth. The increased risk of low birth weight and small gestational age appeared to be mainly restricted to women who had received prior chemotherapy.
Pregnancy after breast cancer it was not associated with poor outcomes in patients. Compared with breast cancer patients who did not have a subsequent pregnancy, those who did become pregnant had a 44 percent lower risk of death and a 27 percent lower risk of disease recurrence.
When the “mother san effect” is controlled for, “which suggests that women who feel well and have a good prognosis are the most likely to try to conceive, women who became pregnant had a 48% lower risk of death and a 26% risk of disease recurrence.
The analysis further indicated that pregnancy seemed safe in all BRCA states, lymph node state, prior chemotherapy exposure, pregnancy interval (the amount of time between breast cancer diagnosis and pregnancy), and pregnancy outcomes.
Overall, Lambertini says, the analysis showed that pregnancy after breast cancer was confirmed to be safe without negatively affecting the prognosis of patients.
A new protocol in Spain
The Spanish Society of Medical Oncology (SEOM), with the participation of the Spanish Association of Surgeons (AEC), the Spanish Society of Gynecology and Obstetrics (SEGO), the Spanish Society of Nuclear Medicine and Molecular Imaging (SEMNIM), the Spanish Society Radiotherapy Oncology (SEOR) and the Spanish Society of Medical Radiology (SERAM), have reached a consensus for the diagnosis and treatment of pregnant women with cancer.
The document provides a guide for action and makes specific recommendations based on the latest diagnostic-therapeutic advances. Thus, for each of the most common tumors in pregnant women, the diagnostic process and possible oncological treatments are detailed, whether pharmacological, surgical or radiotherapy.
The document takes a tour that va from the diagnosis and the techniques used for it depending on each type of cancer, gestational age, treatment and monitoring of the oncological process and the most appropriate periods for each action, always under the premise of maintaining the health of the mother and her growing child.
Diagnosis is one of the key moments in this process and there are two vitally important factors to take into account, the gestational age and the characteristics of the tumor. Likewise, the fetus should be monitored and managed by specialized obstetricians who are part of a multidisciplinary cancer committee. In general, most diagnostic procedures can be performed in pregnant women without endangering the fetus, such as ultrasound, radioprotection mammography, and non-contrast magnetic resonance imaging from the 12th week of gestation.
The document also summarizes current recommendations for the administration of radiation therapy in pregnancy. Although it is generally recommended to delay radiation therapy until postpartum if possible, it may be used if the tumor site is extrapelvic and the planned dose is considered very low risk to the fetus.
In general, certain types of chemotherapy can be administered from the 14th week of gestation (second trimester of pregnancy) without risk to either the fetus or the mother, with appropriate supportive care precautions.
In patients with breast cancer, doxorubicin treatment should be the first option and paclitaxel the second. However, in the first trimester of pregnancy, systemic treatments in general; such as chemotherapy, hormone therapy, targeted therapies and immunotherapy are contraindicated because they carry a risk of malformations and abortion, and no safety data are available during this period.
The surgical interventions During pregnancy is another aspect that this scientific article addresses that agrees that standardized anesthetic procedures for them are considered safe during pregnancy.
The document indicates that depending on the location of the tumor and gestational age, there are indications and appropriate surgical procedures during pregnancy.
Finally, and more specifically and regarding the surgical approach in breast cancer, the most frequent tumor diagnosis during pregnancy, the consensus article points out that in the past, it was erroneously thought that the induction of an abortion could improve the prognosis of the patient, but this assumption is no longer supported by current scientific evidence.
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