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Former Alone Australia winner Gina Cheek was diagnosed with breast cancer just days after finding out she was pregnant. In his current book he describes his experiences with chemotherapy and what happened next. Fortunately, cancer is rarely diagnosed during pregnancy or a year after birth. However, such incidents are becoming increasingly common in parts of the world, including Australia. Researchers don't know exactly why. What researchers know so far and what treatment options are available: A study in New South Wales found that in 1994, for every 100,000 women who gave birth, about 94 cases of cancer were diagnosed during pregnancy or in the first year of childbirth. In 2013 it rose to 163 per 100,000 people. Although these statistics are more than 10 years old, they are the most current and accurate data available in Australia. A 2023 Swedish study of pregnancies from 1973 to 2017 showed similar results. Both studies found that about a quarter of pregnancy-related cancers are diagnosed before birth and the remainder are diagnosed in the first year after birth. The first comprehensive assessment of cancer in pregnancy in the UK was diagnosed between 2016 and 2020.

This study, the New South Wales study and others found that breast cancer and skin cancer (mainly melanoma) were the most common cancers associated with pregnancy. This group also had higher rates of thyroid cancer, gynecological cancers (especially cervical and ovarian cancers), and blood cancers. A British study found that about 92% of cancers were newly diagnosed and about 82% had symptoms. The majority (81%) received treatment with curative intent, and approximately 82% of pregnancies associated with a cancer diagnosis resulted in a live birth. However, at the end of the five-year study period, 20 percent of the mothers had died. Of particular concern was gastrointestinal cancer. These patients had the highest mortality rate of about 46% and were diagnosed with cancer at a more advanced stage. This may be because many symptoms of gastrointestinal cancer, such as abdominal pain, fatigue, and acid reflux, overlap with pregnancy symptoms. In other words, some cancer symptoms can be confused with pregnancy symptoms, potentially “masking” and delaying the cancer diagnosis. There are different types of cancer that occur during and after pregnancy and different factors may be considered. In countries with high socioeconomic standards, women have children at older ages and age is the greatest risk factor for many types of cancer. However, the evidence that age is a significant factor in pregnancy-related cancers is inconclusive. This is true in some cases, but not in all. Another factor could be the increased use of prenatal genetic screening tests in early pregnancy. They analyze DNA from the mother's blood to detect chromosomal abnormalities in the developing fetus. However, these tests also provide information about the mother's chromosomes. This has led to the diagnosis of Hodgkin's disease, breast cancer and colon cancer in asymptomatic pregnant women. Estrogen and progesterone are two hormones that are important for supporting the growth and development of breast tissue and other aspects of a healthy pregnancy.

These can also contribute to the development of cancer, especially breast cancer. However, it is unclear whether this is associated with an increased incidence of pregnancy-related cancers. Other types of cancer, such as skin cancer, are related to environmental factors such as UV radiation. Of note, melanoma was the predominant cancer associated with pregnancy in the New South Wales study, indicating a high prevalence of skin cancer in the local population. Other environmental factors such as smoking and human papillomavirus have also been linked to cervical cancer. Again, we do not know whether such factors are associated with an increased incidence of pregnancy-related cancers. Pregnancy complicates the diagnosis of cancer because possible treatments for the mother can endanger the health and life of the fetus. Therefore, some aspects of treatment may need to be adjusted. Depending on where the cancer originated, the surgery can usually be performed any trimester.

Radiation therapy requires careful planning because the effects of radiation on the fetus depend on the stage of development, the location of exposure to the body, and the dose. Chemotherapy should be avoided in early pregnancy due to its possible toxic effects on the fetus. However, as a rule, it can be prescribed in the second and third trimesters of pregnancy. To reduce the risk of bleeding and infection in infants whose immune systems may be weakened by chemotherapy, chemotherapy should be avoided in the first three weeks of life. More targeted immunotherapy is usually given to the mother after birth. Depending on the type of treatment, you may be advised to stop breastfeeding. This medication can be passed from mother to child through breast milk. Reassuringly, data from New South Wales shows that there is no increased proportion of neonatal deaths before or after birth in babies born to mothers with pregnancy-related cancers.

However, planned premature births were even more common. This is because women are offered an induction and/or cesarean section to make cancer treatment easier for the mother while reducing treatment-related risks to the fetus. There is also a high proportion of babies born with low birth weight and a low Apgar score (an index of the baby's condition immediately after birth), which is likely related to preterm birth. We still have a lot to learn about what's behind the rise in pregnancy-related cancers and what women can expect when diagnosed. There is also a need to integrate cancer and obstetric data into national databases. This will inform which areas should be prioritized for future research, as well as clinical guidelines for cancer screening during pregnancy and beyond, and help assess the response to future screening programs and treatments.