Prognostic significance of marital status in breast cancer survival: A population-based study

<div><p>Research shows that married cancer patients have lower mortality than unmarried patients but few data exist for breast cancer. We assessed total mortality associated with marital status, with attention to differences by race/ethnicity, tumor subtype, and neighborhood socioeconomic status (nSES). We included, from the population-based California Cancer Registry, women ages 18 and older with invasive breast cancer diagnosed between 2005 and 2012 with follow-up through December 2013. We estimated mortality rate ratios (MRR) and 95% confidence intervals (CI) for total mortality by nSES, race/ethnicity, and tumor subtype. Among 145,564 breast cancer cases, 42.7% were unmarried at the time of diagnosis. In multivariable-adjusted models, the MRR (95% CI) for unmarried compared to married women was 1.28 (1.24–1.32) for total mortality. Significant interactions were observed by race/ethnicity (<i>P</i><0.001), tumor subtype (<i>P</i><0.001), and nSES (<i>P</i> = 0.009). Higher MRRs were observed for non-Hispanic whites and Asians/Pacific Islanders than for blacks or Hispanics, and for HR+/HER2+ tumors than other subtypes. Assessment of interactive effect between marital status and nSES showed that unmarried women living in low SES neighborhoods had a higher risk of dying compared with married women in high SES neighborhoods (MRR = 1.60; 95% CI: 1.53–1.67). Unmarried breast cancer patients have higher total mortality than married patients; the association varies by race/ethnicity, tumor subtype, and nSES. Unmarried status should be further evaluated as a breast cancer prognostic factor. Identification of underlying causes of the marital status associations is needed to design interventions that could improve survival for unmarried breast cancer patients.</p></div

Sociodemographic, clinical, and treatment characteristics of patients diagnosed with breast cancer, according to marital status, California, 2005–2012.

<p>Sociodemographic, clinical, and treatment characteristics of patients diagnosed with breast cancer, according to marital status, California, 2005–2012.</p

Adjusted mortality rate ratios (MRR) and 95% confidence intervals (CIs) for total mortality associated with unmarried vs. married patients, by race/ethnicity, tumor subtype, neighborhood socioeconomic status (SES), nativity, and Asian/Pacific Islander (API) subgroups, California, 2005–2012.

<p>Adjusted mortality rate ratios (MRR) and 95% confidence intervals (CIs) for total mortality associated with unmarried vs. married patients, by race/ethnicity, tumor subtype, neighborhood socioeconomic status (SES), nativity, and Asian/Pacific Islander (API) subgroups, California, 2005–2012.</p

Kaplan-Meier curve of all-cause survival by marital status and neighborhood SES, California, 2005–2012.

<p>Kaplan-Meier curve of all-cause survival by marital status and neighborhood SES, California, 2005–2012.</p

Adjusted mortality rate ratio (MRR) and 95% confidence intervals (CI) for total cancer mortality associated with marital status, California, 2005–2012.

<p>Adjusted mortality rate ratio (MRR) and 95% confidence intervals (CI) for total cancer mortality associated with marital status, California, 2005–2012.</p

Associations between parity and lifetime breastfeeding and luminal A and triple-negative breast cancer.

*<p>Adjusted for age at diagnosis, age at menarche, age at first full-term pregnancy, menopausal status and family history.</p

Associations between breast cancer risk factors/tumor characteristics and triple-negative breast cancer.

*<p>Adjusted for age at diagnosis, age at menarche, menopausal status and family history except in models with any of these variables as main predictors.</p>**<p>Further adjusted for age at first full-term pregnancy.</p

Characteristics of the breast cancer patients included in the study (N = 510).

<p>Characteristics of the breast cancer patients included in the study (N = 510).</p

Clinicopathological, karyometric, and immunohistochemical characteristics of breast cancer by family history.

1<p>Ps for categorical variables were estimated from χ² tests. P for the comparison of median ages was esimated from Wilcoxon Rank-Sum test and Ps for other continuous variables were estimated from t-tests.</p>2<p>Histology, lymph node metastasis, grade, MIB1, P53 expression and DNA ploidy index were unknown for 11, 48, 2, 7, 106, 121, 230 and 1 cases, respectively.</p>3<p>Data on nuclear are, perimeter and DNA shape were available for only 353 cases.</p>4<p>Mean ±standard deviation.</p

Family history and breast cancer subtypes further stratified by DNA ploidy.

1<p>Subjects with missing information of ER, PR, or family history were removed from analyses.</p>2<p>Results were estimated from case-only logistic regressions with adjustment for age at diagnosis.</p