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

Abstract

We examined the associations between breast cancer diagnosed during pregnancy and up to 5 years postpartum and total mortality. Breast cancer patients were identified from the Taiwan Cancer Registry (2002-2014). All pregnancies up to 5 years before breast cancer diagnosis were abstracted from the National Health Insurance database and data were then linked to the Taiwan National Death Certificate Database. Follow-up was calculated from the date of breast cancer diagnosis to the date of death or 31 December, 2014, whichever came first. The hazard ratios (HRs) and the 95% confidence intervals (CI) of the association between pregnancy and total mortality were estimated using Cox proportional hazard models. Among the 30,230 breast cancer patients, 90 were diagnosed during pregnancy, 347 within a year postpartum, and 1993 during 1-5 years postpartum. By the end of 2014, 2,920 patients were dead. The major cause of death was breast cancer (89%). Compared to patients without pregnancy records, the HRs were 1.42 (95% CI = 0.83-2.45) for patients diagnosed during pregnancy, 1.29 (0.96-1.74) for those diagnosed within a year postpartum, 1.27 (0.95-1.70) for those diagnosed within 1 to 2 years postpartum, and 1.06 (0.88-1.27) for those diagnosed ≥2 to 5 years postpartum, after adjustment for tumor characteristics and treatment. Subgroup analyses revealed an increased risk of mortality for patients diagnosed within a year postpartum in ER+ cancers (HR = 2.11, 95% CI = 1.28-3.47). Our results suggested a recent pregnancy may be associated with higher mortality among ER+ patients.

Clinicopathological characteristics, diagnosis, and prognosis of pregnancy‐associated breast cancer

“…Our results suggest that PABC could be characterized by more adverse tumor characteristics. HER2 overexpression (22.9%) and triple‐negative breast cancer (22.9%) were the more common molecular subtypes, which is consistent with the findings of several other reports …”

“…Although several previous studies have reported that PABC prognosis is similar to that of non‐PABC when matching for stage, age, and histology, most studies have reported that PABC is associated with a poorer prognosis . In our study, the tumor was aggressive with more patients at advanced T/N stage, and the five‐year OS and DFS rates were 72.3% and 56.1%, respectively, which indicated a poorer prognosis compared to non‐PABC patients.…”

“…HER2 overexpression (22.9%) and triple-negative breast cancer (22.9%) were the more common molecular subtypes, which is consistent with the findings of several other reports. 7 PABC requires multidisciplinary comprehensive treatment, including surgery, chemotherapy, radiotherapy, endocrine therapy, and trastuzumab targeted therapy. Whether pregnancy termination can improve PABC prognosis remains controversial.…”

“…Previous studies have yielded controversial results regarding PABC prognosis. Most studies describe it has having adverse biological characteristics with a relatively poor outcome, while other studies have suggested that the poor survival rates are the result of adverse pathologic features rather than pregnancy …”

“…Previous studies have yielded controversial results regarding PABC prognosis. Most studies describe it has having adverse biological characteristics with a relatively poor outcome, [5][6][7][8] while other studies have suggested that the poor survival rates are the result of adverse pathologic features rather than pregnancy. 9,10 In this retrospective study we reviewed the clinical characteristics, imaging, and pathologic features of 142 PABC patients who had been diagnosed and treated in our hospital to evaluate the therapeutic strategies and analyze prognostic factors.…”