Helping cancer survivors to effectively plan for future pregnancies

A calendar, a positive pregnancy test and an ultrasound photograph

Data access has been approved for a study which aims to help young women with cancer to make informed decisions on their treatment as it relates to their childbearing future.

The study, funded by the Canadian Institutes of Health Research (CIHR), is being led by Dr. Amy Metcalfe, Associate Professor at the University of Calgary.

Cancer is the second leading cause of death in reproductive aged women globally and treatment for this population is impacted by pregnancy and desires for future fertility. Understanding how long-term survival, cancer recurrence, obstetrical and perinatal outcomes each differ by the timing of pregnancy in cancer survivors is important, as approximately 25% of female cancer survivors go on to have a pregnancy.

Cancer treatment during pregnancy presents many clinical challenges as physicians strive to treat the cancer, while balancing fetal and obstetric risks. Long-term follow-up studies of children exposed to chemotherapy in utero are scarce and typically involve small case series with follow-up occurring at variable time points. Importantly, due to concerns about fetal health, iatrogenic preterm birth is often used in this population to avoid fetal exposure to chemotherapy; however, preterm birth is a known risk factor for adverse child development.

Given that the incidence of cancer increases with age, and that delayed childbearing is also associated with an increased risk of adverse obstetrical outcomes, unnecessary delays in pregnancy planning in this population might be avoided, especially if there is no appreciable difference in long-term survival or cancer recurrence, but a demonstrated higher risk of adverse obstetrical and perinatal outcomes.

The study will determine survival and cancer recurrence rates in women diagnosed with cancer during pregnancy or within 365 days after delivery and look at whether the time interval between a pre-pregnancy diagnosis of cancer and estimated date of conception is associated with risk of adverse obstetrical and perinatal outcomes.

The project will also evaluate the health status of children born to women with cancer who were, or were not, treated with chemotherapy during pregnancy, each compared to a) children who were not exposed to cancer in utero and b) its sibling born when the mother did not have cancer.

Among pregnant women with cancer (with or without chemotherapy), Dr. Metcalfe’s team aim to estimate the proportion of adverse child health outcomes that can be attributed to the cancer, treatment with chemotherapy, and provider-initiated preterm birth.

“In addition to providing important baseline data that can be used to counsel young women faced with a new cancer diagnosis during this time, this study will also identify reproductive, tumor and treatment related factors associated with improved prognosis,” says Dr. Metcalfe. “It will also generate new evidence to permit evidence-based communication between patients and their care providers, allowing women to make truly informed treatment decisions best in line with their personal treatment and reproductive goals.”

PopData will link multiple data sets from the BC Ministry of Health, BC Cancer and Perinatal Services BC for the project.