Cancer in pregnancy is an uncommon event. It occurs approximately once per 1,000 pregnancies annually, which corresponds to 0.07% to 0.1% of all malignancies. Notably, its incidence has been increasing in recent years, probably brought about by the higher rates of cancer in general and from a trend towards delayed childbearing to the third and fourth decades. The most common malignancies seen during pregnancy are breast cancer, cervical cancer, lymphoma, ovarian cancer, and melanoma.¹ The pathophysiology of cancer associated with pregnancy has not yet been fully elucidated, but hormonal changes, immunosuppression, and other anatomic changes associated with pregnancy have been proposed mechanisms.²

Currently, pregnant and non-pregnant women with cancer have comparable survival rates, and pregnancy per se doesn’t worsen the disease outcome.³ However, pregnancy-associated cancer remains a challenging condition that should be appropriately diagnosed and managed in order to optimize both maternal and fetal outcomes. Cancer itself rarely affects the developing fetus directly, but the lack of knowledge and experience about this complicated condition could present significant harm to both the mother and her baby. Several factors may lead to a delay in the diagnosis of gestational cancer, including overlapping symptoms with physiological changes associated with pregnancy, physical examination limitations, imaging restrictions, and decreased utility of certain laboratory tests. Treatment decisions are also made more difficult by the lack of data from large studies supporting the safety of anti-cancer therapies, forcing clinicians to rely on limited studies.¹

Every clinical scenario requires careful consideration of the risks and benefits to both parties, which should be addressed using a multidisciplinary approach involving the obstetrician-gynecologist, oncologist, maternal-fetal medicine specialist, neonatologist, psychosocial support services and other concerned healthcare professionals.¹ With proper guidance and effective collaboration, cancer treatment can still be safely administered in most cases with good maternal and fetal outcomes. Several important factors need to be weighed in, including the stage of the pregnancy; the type, location, and stage of the cancer; and the preferences of the woman and her family.⁴

Treatment is usually delayed until the second or third trimester since the risk of congenital malformations is highest during the first trimester. Surgery is considered the safest form of treatment during all stages of pregnancy and shouldn’t be delayed if indicated.³ Some chemotherapy drugs can also relatively be safely administered during the second and third trimesters, except within three weeks of the scheduled delivery date. However, there’s still an increased risk of intrauterine growth retardation, premature rupture of membranes, and premature labor, so fetal monitoring during each treatment cycle should be performed.²

The delivery period in clinical practice is still highly controversial, and is largely dependent upon the maternal-fetal status as well as the type of cancer.⁵ If it becomes necessary to continue chemotherapy after delivery, breastfeeding should be avoided. While long-term safety data are limited, the few studies available show that exposed individuals have normal growth and development.² On the other hand, radiotherapy and hormonal therapy are generally contraindicated. Novel drugs such as targeted therapies and immunotherapies still have very limited data among pregnant women with cancer.⁵

A woman with cancer during pregnancy faces a real paradox, with pregnancy being a symbol of new life and cancer being a potential threat to her life and that of her child. Two critical events happening simultaneously accompanied by conflicting emotions and difficult decisions can lead to significant levels of anxiety and distress. These can also place a huge strain on the relationship of the pregnant woman with her partner.³

It has been observed that maternal exposure to stressful events during pregnancy is associated with adverse neonatal outcomes such as preterm birth, low birth weight, and neurodevelopmental impairment. Distress during pregnancy has also been shown to affect mother-infant attachment, which may have a negative impact on maternal identity and child development.⁶ Hence, a holistic approach to patient care by a multidisciplinary team is recommended, taking into consideration the emotions and concerns of patients in order to identify the kind of psychosocial and emotional support services that they need. It is important to listen, respect, and acknowledge the patient’s values and concerns, as well as to provide reassurance that they are not alone. Open communication and collaboration between the patient, her family, and the medical team are instrumental to ensuring the best possible outcomes for both the mother and her baby.⁷

Because of the possible permanent effects of cancer treatments, another issue that deserves special attention when managing patients with gestational cancer is fertility preservation. The American Society of Clinical Oncology recommends that physicians discuss fertility and future pregnancy issues, including referral to reproductive specialists, as soon as possible before initiating treatment.⁸ However, women should also be educated on the need for continued surveillance because of the risks of recurrence with future pregnancies. Most recommendations advise allowing for a disease-free period of two years after treatment before attempting another pregnancy. It’s equally important to recognize the consequences of an unintended pregnancy during or following cancer treatment, and contraception planning has the potential to avert these ethically and morally challenging dilemmas.¹

While cancer during pregnancy can become extremely stressful and conflicting to all parties involved, a multidisciplinary team of doctors working together with the patient in shared decision-making is key to optimizing maternal and fetal outcomes. Important information should be communicated in a clear, evidence-based, and unbiased manner, and should take into consideration the patient’s concerns, principles, and priorities in life.⁹ The right kind of support can also go a long way in helping the patient get through the unique challenges of childbearing in the face of cancer.

Originally published in HealthToday Issue 1 2021

References:
1. Salani R, Billingsley CC, Crafton SM. Am J Obstet Gynecol 2014;211(1):7–14. 2. Hepner A, Negrini D, Hase EA et al. World J Oncol 2019;10(1):28–34. 3. Ferrari F, Faccio F, Peccatori F et al. BMC Psychol 2018;6(10). 4. Cancer.Net. Cancer during pregnancy. Cancer.Net resource page. Available at: https://www.cancer.net/navigating-cancer-care/dating-sex-and-reproduction/cancer-during-pregnancy. Accessed 20 November 2020.5. Miyamoto S, Yamada M, Kasai Y et al. Jpn J Clin Oncol 2016;46(9):795–804. 6