Tumor characteristics and prognosis in women with pregnancy‐associated breast cancer

Abstract

There is evidence of poor prognosis in women with pregnancy-associated breast cancer (PABC) diagnosed during pregnancy or within 2 years of delivery. Using a large, population-based cohort, we examined clinicopathologic features and survival in women with PABC. A cohort of women diagnosed with invasive breast cancer between 1992 and 2009 at ages 15-44 years was identified in the Swedish Cancer Register and the Breast Cancer Quality Registers. Dates of childbirths for each woman were retrieved from the Swedish Multi-Generation Register. Age-standardized distributions of tumor stage (tumor size, nodal status, metastasis), Elston grade and ER/PR/HER2 status were compared between nulliparous women and women with breast cancer during pregnancy and up to 10 years postdelivery. Adjusted hazard ratios for all-cause mortality rates among patients were estimated using Cox regression. We identified 1,661 nulliparous women with breast cancer, 778 women with PABC (97 during pregnancy, 270 within first and 411 within second year postdelivery) and 3,598 during 2-10 years postdelivery. Compared to nulliparous women, women with PABC, and especially women diagnosed 0-12 months after delivery, had more advanced T and N stage, and higher proportions of ER/PR negative, HER2 positive and triple-negative tumors. Increased hazard ratios were observed in women diagnosed within 5 years of delivery after adjustment for age, year, education and region. Following additional adjustment for tumor characteristics, the hazard ratios were attenuated and nonsignificant. The poorer prognosis observed in women with PABC appears to be largely explained by more adverse tumor characteristics at diagnosis.

Diagnostic pathways and management in women with pregnancy-associated breast cancer (PABC): no evidence of treatment delays following a first healthcare contact

“…Women with PABC receive similar diagnostic workup, with consideration given to pregnancy, and treatment reflecting stage and tumour biology. The previously observed poorer prognosis in patients with PABC in this study population is therefore unlikely to reflect diagnostic or treatment delays [5, 32, 33]. …”

“…During 0–6 months postpartum, most Swedish women breastfeed, and we have previously reported adverse tumour characteristics (i.e. triple-negative, nodal spread) and a poorer prognosis in this patient group [5, 32, 33]. During 6–12 months postpartum, breastfeeding occurs partially, while only a few women still breastfeed between months 12–24 months postpartum.…”

“…During 6–12 months postpartum, breastfeeding occurs partially, while only a few women still breastfeed between months 12–24 months postpartum. However, an improved prognosis has been observed in both these time windows (6–12, 12–24 months postpartum) compared to the pregnancy and 0–6 months postpartum windows [5, 32]. Hence, it is of particular importance to evaluate delays in diagnosis and management in the pregnancy and early postpartum windows separately.…”

Association of pregnancy and mortality in women diagnosed with breast cancer: A Nationwide Population Based Study in Taiwan

“…However, a recent study in Sweden suggested that the elevated 5‐year and 10‐year mortality were only observed for patients diagnosed within 5 years after their latest pregnancy. The association was not statistically significant for patients diagnosed more than 5 years after latest pregnancy, and these associations attenuated after adjustment for tumor characteristics …”

Clinical Characteristics and Prognosis of Pregnancy-Associated Breast Cancer: Poor Survival of Luminal B Subtype

“…However, recent studies have shown that there is no difference in prognosis between breast cancer during pregnancy and non-PABC; in cases of breast cancer during the postpartum period, the prognosis was poor [7, 26]. Recent data suggest that breast cancer diagnosed in the postpartum period has a worse prognosis than nulliparous women, and the risk of breast cancer increases by 5 years after delivery [27, 28], with a 2.8-fold higher rate of distant metastasis and a 2.65-fold higher mortality rate than those diagnosed up to 5 years after delivery [29]. In this database, breast cancer was compared with women of childbearing age because of limited data.…”