Survival in Women Diagnosed With Breast Cancer During Pregnancy

Procedural abortion, provider-initiated preterm delivery and survival in pregnant people with cancer: A population-based cohort study

OBJECTIVE

To assess whether procedural-induced abortion or provider-initiated preterm delivery are associated with improved survival in pregnant people with cancer.

DESIGN

Retrospective population-based cohort study.

SETTING

Provinces of Alberta and Ontario, Canada, 2003-2016.

POPULATION

Females aged 18-50 years diagnosed with cancer at <20 weeks' (for the assessment of procedural-induced abortion) or <37 weeks' gestation (for the assessment of provider-initiated delivery).

METHODS

Cox proportional hazard models assessed all-cause mortality in relation to procedural-induced abortion and provider-initiated preterm delivery, adjusting for cancer site, stage at diagnosis and age. Meta-analysis pooled the results across both provinces.

MAIN OUTCOME MEASURES

All cause mortality.

RESULTS

There were 512 pregnant people diagnosed with cancer at <20 weeks' gestation and 782 diagnosed with cancer at <37 weeks' gestation. Neither procedural-induced abortion (adjusted hazard ratio [aHR] = 1.39, 95% CI: 0.32-6.17) nor provider-initiated preterm delivery (aHR = 1.17, 95% CI: 0.76-1.81) were associated with improved survival following adjustment for age, stage at diagnosis and cancer site.

CONCLUSIONS

Neither procedural-induced abortion nor provider-initiated preterm birth was associated with improved survival in pregnant people diagnosed with cancer; however, these obstetric interventions are highly personal decisions best decided by the pregnant person in consultation with their care providers.

Worse histopathology and prognosis in women with breast cancer diagnosed during the second trimester of pregnancy

BACKGROUND

Evidence suggests that women with breast cancer diagnosed during pregnancy (PrBC) and within 2 years of delivery (PPBC) have similar survival compared to women diagnosed not near pregnancy if adjusted for stage and subtype. To investigate whether this is true for all subtypes and for both pregnancy and post-delivery periods, we examined clinicopathologic features and survival in women with breast cancer by trimesters and 6-month post-delivery intervals.

MATERIALS AND METHODS

Women diagnosed with invasive breast cancer during 1992-2018 at ages 18-44 years were identified in the Swedish Cancer Register, with information on childbirths from the Swedish Multi-Generation Register and clinical data from Breast Cancer Quality Registers. Each woman with PrBC or PPBC was matched 1 : 2 by age and year to comparators diagnosed with breast cancer not near pregnancy. Distributions of stage, grade, and surrogate subtypes were compared. Adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for breast cancer mortality were estimated using Cox regression.

RESULTS

We identified 1430 women with PrBC and PPBC (181 during pregnancy, 499 during the first and 750 during the second year after delivery). Compared to 2860 comparators, women with PrBC and PPBC in the first year after delivery had a significantly higher proportion of luminal human epidermal growth factor receptor 2 (HER2)-positive, HER2-positive and triple-negative tumours, and more advanced stage at diagnosis. After adjustment for age, year, parity, country of birth, hospital region, subtype, and stage, women diagnosed during the second trimester had a worse prognosis than matched comparators (HR 1.8, 95% CI: 1.0-3.2).

CONCLUSIONS

Women diagnosed during pregnancy or within the first year after delivery have a worse prognosis than women diagnosed not near pregnancy due to adverse tumour biology and advanced stage at diagnosis. A worse prognosis for women diagnosed during the second trimester remained after multivariable adjustment, possibly reflecting difficulties to provide optimal treatment during ongoing pregnancy.

Survival in pregnancy-associated breast cancer patients compared to non-pregnant controls

BACKGROUND

Pregnancy-associated breast cancer (PABC) is a rare entity whose prognosis has previously been studied and is subject to controversy.

METHODS

Survival of patients with PABC diagnosed between 2009 and 2021 with breast cancer during pregnancy or until 1 year after childbirth was compared with non-pregnant patients with breast cancer from the same period at La Paz University Hospital. Cox proportional hazards regression was used to compare disease-free (DFS) and overall (OS) survival between the groups, adjusting for grade and pathologic stage.

RESULTS

Among the 89 included patients with breast cancer, 34 were diagnosed during pregnancy, and 55 were not pregnant. The pregnant patients were more likely to have grade 3 tumors (61.3% vs 37%, p = 0.023) and an advanced stage (pathologic stage III-IV: 44.1% vs 17.6%, p = 0.008). Median follow-up was 47 months for the pregnant group and 46 months for the control group. After adjustments for tumor grade and pathologic stage, OS was comparable between the groups (HR 2.03; 95% CI 0.61 to 6.79; P = 0.25).

CONCLUSIONS

The outcome of women diagnosed with PABC is comparable to young non-pregnant controls. However, it should be taken into account that PABC has a more aggressive phenotype.