Pregnancy-Associated Cancer Correlates With Increased Long-Term Mortality

Pregnancy-associated cancers appeared to have increased 5-year overall mortality rates, although outcomes may depend on disease site and whether the diagnosis was during pregnancy or post-partum, according to findings from a population-based meta-analysis published in JAMA Oncology.

"More research on each cancer site is required to provide robust evidence to guide counseling and clinical care of affected patients," according to the study authors.

The 1-year overall survival (OS) rates were 97% (95% CI, 96%-98%) for patients diagnosed with cancer during pregnancy, 96% (95% CI, 96%-97%) for those diagnosed during postpartum, and 98% (95% CI, 98%-98%) for those diagnosed during periods remote from pregnancy and post-partum. The 5-year OS rates for each respective group were 87% (95% CI, 84%-89%), 89% (95% CI, 88%-90%), and 93% (95% CI, 92%-93%).

After adjusting for age and disease stage at diagnosis, cancer site, and days to first treatment, patients diagnosed with cancer during pregnancy or postpartum had an increased mortality risk (adjusted hazard ratio [aHR], 1.57; 95% CI, 1.42-1.74). This mortality risk remained elevated when comparing pregnancy (aHR, 1.79; 95% CI, 1.51-2.13) and postpartum (aHR, 1.49; 95% CI, 1.33-1.67) diagnoses with cancers diagnosed during remote periods from pregnancy.

Investigators observed increased mortality risks for patients with breast (aHR, 2.01; 95% CI, 1.58-2.56), ovarian (aHR, 2.60; 95% CI, 1.12-6.03), and stomach cancers diagnosed during pregnancy (aHR, 10.37; 95% CI, 3.56-30.24). Additionally, there was an increased mortality risk for those diagnosed with brain (aHR, 2.75; 95% CI, 1.28-5.90), breast (aHR, 1.61; 95% CI, 1.32-1.95), and melanoma skin cancer (aHR, 1.84; 95% CI, 1.02-3.30) during postpartum.

“This population-based cohort study found that pregnancy-associated cancers had an overall increased mortality compared with cancer occurring remotely from pregnancy, and death rates varied greatly depending on cancer site and timing of diagnosis,” the study authors stated. “More research on each cancer site is required to provide robust evidence to guide counseling and clinical care of affected patients.”

Investigators of this population-based retrospective cohort study included data from premenopausal women aged 18 to 50 years who had cancer diagnoses between January 1, 2003, and December 31, 2016, with follow-up until December 31, 2017. Investigators categorized patients as being diagnosed with cancer during pregnancy or from conception to delivery (n = 1014), during the postpartum period or up to 1 year after delivery (n = 3074), or during a period remote from pregnancy (n = 20,219). The study included administrative data from Canadian provinces including Alberta, British Columbia, and Ontario.

The primary end point was OS at 1 and 5 years as well as the time from cancer diagnosis to any-cause death. Estimations of mortality aHRs with 95% CIs adjusting for age at cancer diagnosis, cancer stage, cancer site, and days from diagnosis to first treatment involved the use of Cox proportional hazard models.

The median patient age at diagnosis was 31.9 years for those diagnosed during pregnancy, 32.6 years for those diagnosed during the postpartum period, and 36.5 years for those diagnosed remote from pregnancy. In the pregnancy and postpartum diagnosis groups, respectively, the mean gestational age at delivery was 37.0 weeks vs 38.5 weeks, and the preterm birth rate was 32% vs 10%.

Of the patients diagnosed during pregnancy and those diagnosed remotely from pregnancy, respectively, 26.0% and 30.0% had breast cancer. Of those diagnosed postpartum, 24.0% had thyroid cancer.

Investigators noted reduced survival for patients with cancer of the upper digestive tract diagnosed during pregnancy (HR, 3.08; 95% CI, 1.78-5.36), colon cancer diagnosed postpartum (HR, 1.42; 95% CI, 1.02-1.99), and uterine cancer diagnosed postpartum (HR, 8.51; 95% CI, 2.76-26.2). There were no statistically significant differences in survival for patients with cutaneous malignant melanoma or cervical cancer diagnosed during pregnancy or postpartum.

Reference

Cairncross ZF, Shack L, Nelson G, et al. Long-term mortality in individuals diagnosed with cancer during pregnancy or postpartum. JAMA Oncol. Published online April 6, 2023. doi:10.1001/jamaoncol.2023.0339