Cancer during pregnancy is sporadic, but is becoming more common. Here’s what researchers think is behind the augment

Former Alone Australia winner Gina Chick diagnosed from breast cancer just days after finding out she was pregnant. She describes in his last book her experience with chemotherapy and what came after it.

Fortunately, cancers diagnosed during pregnancy and in the year after delivery are sporadic. But such cases are becoming more and more common in parts With world, including Australia. Scientists aren’t entirely sure why.

Here’s what scientists know so far and treatment options.

How sporadic is this?

Modern South Wales test found that in 1994, for every 100,000 women giving birth, approximately 94 cancers were diagnosed during pregnancy or within one year of birth. In 2013, this number increased to around 163 per 100,000. Although these statistics are over a decade aged, they are the latest and most demanding data available in Australia.

Swede from 2023 test pregnancies in the years 1973–2017 showed similar results.

Both studies found that about a quarter of pregnancy-related cancers are diagnosed before birth, with the rest diagnosed a year after birth.

What type of cancer are we talking about?

First in the UK comprehensive assessment cancer during pregnancy – a review of diagnoses from 2016–2020.

This study, the NSW study and others found that breast and skin cancer (often melanoma) are the most common cancers associated with pregnancy. In this group, there was also a high percentage of thyroid cancer, gynecological cancer (especially cervical and ovarian cancer) and blood cancer.

A UK study found that around 92% of cancers were up-to-date diagnoses and around 82% had symptoms. The majority (81%) were treated with curative intent, and approximately 82% of pregnancies associated with a cancer diagnosis resulted in a live birth.

However, 20% of the mothers died before the end of the five-year study period. Gastrointestinal cancers were particularly concerning. They were characterized by the highest mortality rate of approximately 46% and were associated with diagnosis at a more advanced stage of cancer.

This may be because many of the symptoms of gastrointestinal cancers, such as abdominal pain, fatigue and acid reflux, overlap with those of pregnancy. In other words, some cancer symptoms can be confused with pregnancy symptoms, “masking” or delaying the diagnosis of cancer.

Why are there more and more such cases?

The wide range of cancers that occur during and after pregnancy suggest that there are many factors involved.

In countries with high socioeconomic status, women have children later in life, and the greatest risk factor for many cancers is age. However, the evidence that age is a major risk factor for pregnancy-related cancers is inconclusive. This may explain some, but not all, cases.

Another factor may be increasing usage prenatal genetic testing in early pregnancy. They analyze DNA from the mother’s blood to detect chromosomal abnormalities in the developing fetus. But these tests can also provide information about the mother’s chromosomes. This has led to the diagnosis of Hodgkin’s disease, breast and colorectal cancer in pregnant women without symptoms.

Estrogen and progesterone are two hormones vital for the growth and development of breast tissue and supporting other aspects of a well pregnancy. They can also contribute to cancer developmentespecially breast cancer. However, it is unclear whether this is related to the augment in pregnancy-related cancers.

Other cancers, such as skin cancer, have been linked to environmental factors such as exposure to UV radiation. Of note, melanoma was the leading pregnancy cancer in the Modern South Wales study, reflecting the high incidence of skin cancer in the local population. Other environmental factors, such as smoking and human papillomavirus, have been linked to cervical cancer. Again, we are not sure whether such factors are associated with the augment in the incidence of pregnancy-related cancers.

What happens after the diagnosis is made?

Pregnancy complicates the diagnosis of cancer because any potential treatment for the mother may jeopardize the health and viability of the fetus. So some aspects of treatment may require adjustment.

Surgery can usually be performed in any trimester of pregnancy, depending on the location of the cancer.

Radiotherapy requires careful planning because the effects of radiation on the fetus depend on the developmental stage at which radiation is administered to the body and on the dose.

Chemotherapy should be avoided in the first trimester of pregnancy due to its potential toxic effects on the fetus. It can usually be given in the second and third trimester of pregnancy. Chemotherapy should be avoided within three weeks of birth to reduce the risk of bleeding and infection in the newborn, who may also have a weakened immune system as a result of chemotherapy.

More targeted immunotherapies are typically given to the mother after delivery. Depending on her treatment, she may be advised not to breastfeed. This is because the medicine can pass from mother to baby through breast milk.

What’s happening to the children?

Reassuringly, data from Modern South Wales showed no augment in the rate of perinatal deaths given to mothers with pregnancy-related cancer.

However, there were more planned premature births. This is because women are offered induction of labor and/or cesarean section to make it easier for the mother to undergo cancer treatment while also reducing the risks of treatment for the unborn baby.

There was also a higher percentage of babies born with low birth weight and low Apgar scores (indicators of a baby’s condition soon after birth), which were probably related to premature birth.

What do researchers want to know?

We still have a lot to learn about what’s behind the rising rates of pregnancy-related cancers and what women diagnosed with this cancer can expect.

We also need to combine cancer and obstetrics data in national databases. This would allow us to determine which areas should be prioritized for further research, provide clinical guidelines for cancer screening during and after pregnancy, and support assess responses to screening programs or therapies in the future.