Association between reproductive factors and breast cancer survival in younger women

Reproductive history and breast cancer survival: Findings from the African breast cancer-Disparities in outcomes cohort and implications of Africa's fertility transition on breast cancer prognosis

Reproductive characteristics are known risk factors for breast cancer but, other than recent birth, their role as prognostic factors is less clear, and has not been studied in Sub-Saharan Africa (SSA). In this setting, we examined whether reproductive factors independently influence breast cancer survival in a subset of the African Breast Cancer-Disparities in Outcomes cohort study. In 1485 women with incident breast cancer recruited between 2014 and 2017, we examined birth cohort changes in reproductive factors, and used Cox models to examine whether reproductive characteristics were associated with all-cause mortality after adjusting for confounders (age, stage, treatment, HIV, and social factors). Four years after diagnosis, 822 (56%) women had died. Median parity was 4 (IQR = 2, 6) and 209 (28%) of premenopausal women had had a recent birth (<3 years prior to cancer diagnosis). Each pregnancy was associated with a 5% increase (95% CI: 2%, 8%) in mortality rates, which held among postmenopausal women (5%, [1%-9%]). Pre-menopausal women with a recent birth had 52% (20%, 92%) higher mortality rates. Fertility trends by birth cohort showed declining parity, increasing age at first birth and declining age at last birth, however the impact of these population-level changes on future average survival was predicted to be very small (<3% absolute gain).

Prognostic effect of subsequent childbirth after the diagnosis of breast cancer using propensity score matching analysis

BACKGROUND

Among younger patients, one of the important concerns is whether they can give birth safely. Although previous studies have investigated this topic, many aspects remain unclear owing to potential biases. We aimed to evaluate the prognostic effect of subsequent childbirth after the diagnosis using propensity score matching.

METHODS

A single-center retrospective cohort study was conducted. This study included patients aged ≤ 45 years, diagnosed with breast cancer between 2005 and 2014. Patients with and without subsequent childbirth were assigned to the childbirth and non-childbirth cohorts, respectively. Relapse-free survival (RFS) and overall survival (OS) of the childbirth cohort were compared with those of the non-childbirth cohort. The covariates in the propensity score model included age, tumor size, node status, number of preceding childbirths before the diagnosis, estrogen receptor, and human epidermal growth factor receptor 2 status.

RESULTS

104 patients with childbirth and 2250 without childbirth were assigned to the respective cohorts. At a median follow-up of 82 months, the childbirth cohort showed a significantly longer RFS than the non-childbirth cohort (HR = 0.469 [0.221-0.992]; p = 0.047). There was no significant difference in the OS (HR = 0.208 [0.029-1.494]; p = 0.119). After matching, subsequent childbirth was not significantly associated with RFS (HR = 0.436 [0.163-1.164], p = 0.098) and OS (HR = 0.372 [0.033-4.134], p = 0.402).

CONCLUSIONS

Subsequent childbirth was not associated with an increased risk of relapse and mortality. It is important to make younger patients aware of these novel findings and aid them in their decision-making.

Survival of women with pregnancy-associated breast cancer according to clinical characteristics: A propensity score matching study

In recent years, postponing childbearing has increased the prevalence of pregnancy-associated breast cancer (PABC). PABC has a poorer prognosis than breast cancer not associated with pregnancy (non-PABC) due to delayed diagnosis and aggressive subtype. Additionally, pregnancy itself predicts a poor prognosis; but, this is a subject of debate. Thus, we analyzed the effects of known prognostic factors and pregnancy on the prognosis of PABC. We retrospectively analyzed women aged 20 to 49 years who were diagnosed with breast cancer (BC) between 1989 and 2014. Patients were distributed into PABC and non-PABC groups, and 1:4 propensity score matching was performed to adjust for baseline characteristics. Primary endpoints were overall survival (OS) and BC-specific survival (BCSS). Secondary endpoint was the difference in prognosis according to BC subtype. Of the 34,970 recruited patients with BC, 410 (1.2%) had PABC. Patients with PABC were younger and tended to have triple-negative BC (TNBC) subtype than non-PABC patients. The 1640 matched non-PABC patients showed a significantly worse mean survival rate than the unmatched non-PABC patients. Patients with PABC had a significantly worse OS and BCSS than those with non-PABC. In multivariate analyses, patients with PABC of luminal B (Ki-67 ≥14.0%) and TNBC subtypes had worse OS and BCSS than patients with non-PABC. Patients with PABC had poorer prognosis than non-PABC patients after adjusting for several prognostic factors. This difference was particularly significant in patients with the luminal B and TNBC subtypes.

Prognostic factors for cancer-specific survival in 220 patients with breast cancer: A single center experience

OBJECTIVES

Hospital-based breast cancer survival studies are scarce in western Iran. Furthermore, the relationship between breast cancer survival and clinical parameters has been extensively studied, but many of the findings come from developing countries. This paper aims to estimate the survival of hospital-based breast cancer patients and its predictor factors.

METHOD

This retrospective analysis was conducted on 578 patients with primary breast cancer who underwent surgery between 2004 and 2020. Information was collected from medical reports by the Hospital information system in Imam Reza Hospital, Kermanshah, Iran. One-, 2-, 5-, and 10-year breast cancer-specific survival has been calculated using the Kaplan-Meier process. Crude and adjusted Hazard Ratios (HR) were calculated using the Cox proportional regression model.

RESULT

One-, 2-, and 5-year overall breast cancer survival were 219 (99.54%), 196 (89.09%), 159 (72.27%), and 70 (31.81%), respectively. Univariate analysis of breast cancer patients with tumor-related variables revealed that factors such as age, menopause status, lymph node metastasis, number of lymph nodes, organ metastasis, and stage of disease were significantly associated with disease-specific survival (p < .05). Multivariate analysis demonstrated that metastasis (HR = 41.77, 95% CI: 15.3-114.15) and lymph node metastasis (HR = 5.26, 95% CI: 1.9-14.6) were significantly related to survival.

CONCLUSION

The findings demonstrate that survival is relatively low and is consistent with late-stage disease diagnosis. It is believed that this is due to a poor level of awareness, lack of screening programs, and subsequent late access to treatment.

Breast cancer treatment patterns by age and time since last pregnancy in the Carolina Breast Cancer Study Phase III

PURPOSE

To describe breast cancer treatment patterns among premenopausal women by age and time since last pregnancy.

METHODS

Data were analyzed from 1179 women diagnosed with premenopausal breast cancer in the Carolina Breast Cancer Study. Of these, 160 had a recent pregnancy (within 5 years of cancer diagnosis). Relative frequency differences (RFDs) and 95% confidence intervals (CIs) were used to compare cancer stage, treatment modality received, treatment initiation delay (> 30 days), and prolonged treatment duration (> 2 to > 8 months depending on the treatment received) by age and recency of pregnancy.

RESULTS

Recently postpartum women were significantly more likely to have stage III disease [RFD (95% CI) 12.2% (3.6%, 20.8%)] and to receive more aggressive treatment compared to nulliparous women. After adjustment for age, race and standard clinical tumor characteristics, recently postpartum women were significantly less likely to have delayed treatment initiation [RFD (95% CI) - 11.2% (- 21.4%, - 1.0%)] and prolonged treatment duration [RFD (95% CI) - 17.5% (- 28.0%, - 7.1%)] and were more likely to have mastectomy [RFD (95% CI) 14.9% (4.8%, 25.0%)] compared to nulliparous. Similarly, younger women (< 40 years of age) were significantly less likely to experience prolonged treatment duration [RFD (95% CI) - 5.6% (- 11.1%, - 0.0%)] and more likely to undergo mastectomy [RFD (95% CI) 10.6% (5.2%, 16.0%)] compared to the study population as a whole.

CONCLUSION

These results suggest that recently postpartum and younger women often received prompt and aggressive breast cancer treatment. Higher mortality and recurrence among recently pregnant women are unlikely to be related to undertreatment.

Impact of breast cancer risk factors on clinically relevant prognostic biomarkers for primary breast cancer

Purpose

In addition to impacting incidence, risk factors for breast cancer may also influence recurrence and survival from the disease. However, it is unclear how these factors affect combinatorial biomarkers for aiding treatment decision-making in breast cancer.

Methods

Patients were 8179 women with histologically confirmed invasive breast cancer, diagnosed and treated in a large cancer hospital in Beijing, China. Individual clinicopathological (tumor size, grade, lymph nodes) and immunohistochemical (IHC: ER, PR, HER2, KI67) markers were used to define clinically relevant combinatorial prognostic biomarkers, including the Nottingham Prognostic Index (NPI: combining size, grade, nodes) and IHC4 score (combining ER, PR, HER2, KI67). Odds ratios (ORs) and 95% confidence intervals (CIs) for associations between breast cancer risk factors and quartiles (Q1–Q4) of NPI and IHC4 were assessed in multivariable polytomous logistic regression models.

Results

Overall, increasing parity (OR_trend(95% CI) = 1.20(1.05–1.37);P_trend = 0.007), overweight (OR(95% CI)_{vs normal} = 1.60(1.29–1.98)), and obesity (OR(95% CI) _{vs normal} = 2.12(1.43–3.14)) were associated with higher likelihood of developing tumors with high (Q4) versus low (Q1) NPI score. Conversely, increasing age (OR_trend(95% CI) = 0.75(0.66–0.84);P_trend < 0.001) and positive family history of breast cancer (FHBC) (OR(95% CI) = 0.66(0.45–0.95)) were inversely associated with NPI. Only body mass index (BMI) was associated with IHC4, with overweight (OR(95% CI) _{vs normal} = 0.82(0.66–1.02)) and obese (OR(95% CI) _{vs normal} = 0.52(0.36–0.76)) women less likely to develop high IHC4 tumors. Notably, elevated BMI was associated with higher NPI irrespective of hormone receptor-expression status.

Conclusions

Our findings indicate that factors affecting breast cancer incidence, particularly age, parity, FHBC, and BMI, may impact clinically relevant prognostic biomarkers with implications for surveillance, prognostication, and counseling.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-021-06294-5.

Factors Affecting Long-Survival of Patients with Breast Cancer by Non-Mixture and Mixture Cure Models Using the Weibull, Log-logistic and Dagum Distributions: A Bayesian Approach

BACKGROUND

Breast cancer is a top biomedical research priority, and it is a major health problem. Therefore, the present study aimed to determine the prognostic factors of breast cancer survival using cure models.

METHODS

In this retrospective cohort analytic study, data of 140 breast cancer patients were collected from Ali Ibn Abi Taleb hospital, Rafsanjan, Southeastern Iran. Since in this study, a part of the population had long-term survival, cure models were used and evaluated using DIC index. The data were analyzed using Openbugs Software.

RESULTS

In this study, of 140 breast cancer patients, 23 (16.4%) cases died of breast cancer. Based on the findings, the Bayesian nonmixture cure model, with type I Dagum distribution, was the best fitted model. The variables of BMI, number of children, number of natural deliveries, tumor size, metastasis, consumption of canned food, tobacco use, and breastfeeding affected patients' survival based on type I Dagum distribution.

CONCLUSION

The results of the present study demonstrated that the Bayesian nonmixture cure model, with type I Dagum distribution, can be a good model to determine factors affecting the survival of patients when there is the possibility of a fraction of cure. In this study, it was found that adapting a healthy lifestyle (eg, avoiding canned foods and smoking) can improve the survival of breast cancer patients.

Age at first childbirth and breast cancer survival: a prospective cohort study

OBJECTIVE

Late age at first childbirth is a well-established risk factor for breast cancer. Previous studies have, however, shown conflicting results to whether late age at first childbirth also influences the prognosis of breast cancer survival. The aim of this study was to examine age at first birth in relation to survival after breast cancer diagnosis.

RESULTS

We used information from the Malmö Diet and Cancer study. At baseline 17,035 women were included. All women were followed from the year they developed breast cancer until they either died or until the end of follow-up. All women were asked how many children they had given birth to and were then divided into different groups, ≤ 20, > 20 to  ≤ 25, > 25 to  ≤ 30 and > 30. Nulliparous women form a separate group. Survival analyses were then performed using Cox proportional hazard survival analysis. Women in all age groups had a lower risk of breast cancer specific death as compared to the reference group ≤ 20, however non-significantly. Nulliparous women had a higher risk of breast cancer specific death as compared to the same reference group, however these results were not statistically significant. We could not see any negative effect of late first childbirth on breast cancer specific survival.

Associations of reproductive factors with breast cancer prognosis and the modifying effects of menopausal status

Reproductive factors associated with breast cancer risk may also affect the prognosis. This study aimed to evaluate the associations of multiple reproductive factors with breast cancer prognosis and the modifying effects of menopausal status. We obtained data from 3805 breast cancer patients recruited between October 2008 and June 2016 in Guangzhou. The subjects were followed up until 30 June 2018. The hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated using multivariate Cox models to estimate the associations. It was found that there were U‐shaped patterns for the associations of age at first birth and durations from first/last birth to diagnosis with breast cancer prognosis. The adverse effects of old age at first birth [>30 years vs 23‐30 years, HR (95% CI): 1.59 (1.01‐2.50)] and long intervals from first [≥20 years vs 10‐19 years, HR (95% CI): 1.55 (1.07‐2.27)] or last [≥20 years vs 10‐19 years, HR (95% CI): 1.63 (1.08‐2.46)] birth to diagnosis on progression‐free survival (PFS) were significantly more pronounced among premenopausal women. Additionally, long interval (>5 years) between first and second birth was associated with a better PFS [HR (95% CI): 0.64 (0.42‐0.97)]. These results suggested that age at first birth, durations from first/last birth to diagnosis, and intervals between first and second birth should be taken into account when following the patients and assessing the prognosis of breast cancer, particularly for premenopausal patients. These findings would also have implications for further insight into the mechanisms of breast cancer development.

The Clinicopathological features and survival outcomes of patients with different metastatic sites in stage IV breast cancer

BACKGROUND

The features and survival of stage IV breast cancer patients with different metastatic sites are poorly understood. This study aims to examine the clinicopathological features and survival of stage IV breast cancer patients according to different metastatic sites.

METHODS

Using the Surveillance, Epidemiology, and End Results database, we restricted our study population to stage IV breast cancer patients diagnosed between 2010 to 2015. The clinicopathological features were examined by chi-square tests. Breast cancer-specific survival (BCSS) and overall survival (OS) were compared among patients with different metastatic sites by the Kaplan-Meier method with log-rank test. Univariable and multivariable analyses were also performed using the Cox proportional hazard model to identify statistically significant prognostic factors.

RESULTS

A total of 18,322 patients were identified for survival analysis. Bone-only metastasis accounted for 39.80% of patients, followed by multiple metastasis (33.07%), lung metastasis (10.94%), liver metastasis (7.34%), other metastasis (7.34%), and brain metastasis (1.51%). The Kaplan-Meier plots showed that patients with bone metastasis had the best survival, while patients with brain metastasis had the worst survival in both BCSS and OS (p < 0.001, for both). Multivariable analyses showed that age, race, marital status, grade, tumor subtype, tumor size, surgery of primary cancer, and a history of radiotherapy or chemotherapy were independent prognostic factors.

CONCLUSION

Stage IV breast cancer patients have different clinicopathological characteristics and survival outcomes according to different metastatic sites. Patients with bone metastasis have the best prognosis, and brain metastasis is the most aggressive subgroup.

Reproductive history and breast cancer survival: a prospective patient cohort study in Japan

BACKGROUND

Reproductive factors may influence breast cancer progression and patient survival; however, evidence has been limited.

METHODS

The associations of reproductive factors with tumor characteristics and patient survival were analyzed among 1468 breast cancer patients diagnosed during 1997-2013 at a single institute in Japan. The patients were followed until 2016. During a median follow-up period of 8.6 years, 272 all-cause and 199 breast cancer deaths were documented.

RESULTS

In case-case comparisons, later age at menarche was inversely associated with advanced tumors. Nulliparous patients tended to have receptor-positive [estrogen receptor (ER)+ or progesterone receptor (PR)+] tumors. Conversely, the Cox proportional-hazards model including adjustment for tumor characteristics revealed U-shaped relationship between parity number and the risk of all-cause death among the patients overall [hazard ratio (HR) = 2.10 for nulliparous, 1.28 for 2, and 1.50 for ≥ 3 vs. one child]. According to hormone receptor, later age at menarche and later age at last birth were positively associated with the risk of all-cause death among patients with ER- and PR- cancer (menarche, HR = 2.18 for ≥ 15 vs. ≤ 12 years, p_trend = 0.03; last birth, HR = 3.10 for ≥ 35 vs. ≤ 29 years, p_trend = 0.01). A shorter time since last birth was associated with the risk of death among receptor-positive patients (HR = 5.72 for ≤ 4 vs. ≥ 10 years, p_trend = 0.004).

CONCLUSION

The results indicate that the timing of menarche and parity have significant effects on patient survival, providing clues for understanding the association between women's life course and breast cancer outcome.

Parity Differently Affects the Breast Cancer Specific Survival from Ductal Carcinoma In Situ to Invasive Cancer: A Registry-Based Retrospective Study from Korea

Purpose:

Multiparity might increase general mortality for women, but has inconclusive in patients with breast cancer. Here, we aim to discover their effect in terms of the breast cancer development hypothesis: from ductal carcinoma in situ to invasive carcinoma.

Methods:

We included 37 947 patients from the web-based breast cancer registration program of the Korean Breast Cancer Society and analyzed survivals using multivariate Cox regression analysis and whether the associations of these factors displayed linear trends. They were divided into the following groups: (1) pure ductal carcinoma in situ (DCIS), (2) invasive ductal carcinoma (IDC) mixed with intraductal component (DCIS-IDC), and (3) node negative pure IDC.

Results:

The mean age was 48.9 ± 9.9 years including premenopausal women was 61.8%. Although patients with parities of 1-3 had better prognosis compared with patients with nulliparous women, high parity (⩾4) increased the hazard ratio (HR) of overall survival (OS) (DCIS: HR, 1.52; 95% confidence interval [CI] 0.62-3.78; IDC: HR, 1.43, 95% CI 0.89-2.31; and DCIS-IDC: HR, 1.44, 95% CI 0.45-4.59) during 84.2 (±10.7) months. For breast cancer specific survival (BCSS), the HR of the IDC group (P-value for trend = .04) increased along with increasing parity and was worse than nulliparous patients, and the HR of the DCIS-IDC group increased but was better than nulliparous patients (P-value for trend = .02). Compared with nulliparous patients, any age at first birth (AFB) decreased HR of OS in the DCIS and IDC groups (DCIS: P = .01; IDC: P = .04).

Conclusions:

Parity show dual effects on OS of women with all ductal typed breast cancer but show different effects on BCSS in Korea.

Breast cancer risk factors, survival and recurrence, and tumor molecular subtype: analysis of 3012 women from an indigenous Asian population

BACKGROUND

Limited evidence, mostly from studies in Western populations, suggests that the prognostic effects of lifestyle-related risk factors may be molecular subtype-dependent. Here, we examined whether pre-diagnostic lifestyle-related risk factors for breast cancer are associated with clinical outcomes by molecular subtype among patients from an understudied Asian population.

METHODS

In this population-based case series, we evaluated breast cancer risk factors in relation to 10-year all-cause mortality (ACM) and 5-year recurrence by molecular subtype among 3012 women with invasive breast cancer in Sarawak, Malaysia. A total of 579 deaths and 314 recurrence events occurred during a median follow-up period of ~ 24 months. Subtypes (luminal A-like, luminal B-like, HER2-enriched, triple-negative) were defined using immunohistochemical markers for hormone receptors and human epidermal growth factor receptor 2 (HER2) in conjunction with histologic grade. Hazard ratios (HRs) and 95% confidence intervals (CIs) for the associations between risk factors and ACM/recurrence were estimated in subtype-specific Cox regression models.

RESULTS

We observed heterogeneity in the relationships between parity/breastfeeding, age at first full-term pregnancy (FFP), family history, body mass index (BMI), and tumor subtype (p value < 0.05). Among luminal A-like patients only, older age at menarche [HR (95% CI) _{≥15 vs ≤ 12 years} = 2.28 (1.05, 4.95)] and being underweight [HR_{BMI < 18.5kg/m}²_{vs. 18.5-24.9kg/m}² = 3.46 (1.21, 9.89)] or overweight [HR_25-29.9kg/m²_{vs. 18.5-24.9kg/m}²₌ 3.14 (1.04, 9.50)] were associated with adverse prognosis, while parity/breastfeeding [HR_{breastfeeding vs nulliparity} = 0.48 (0.27, 0.85)] and older age at FFP [HR _{> 30 vs < 21 years} = 0.20 (0.04, 0.90)] were associated with good prognosis. For these women, the addition of age at menarche, parity/breastfeeding, and BMI, provided significantly better fit to a prognostic model containing standard clinicopathological factors alone [LRχ² (8df) = 21.78; p value = 0.005]. Overall, the results were similar in relation to recurrence.

CONCLUSIONS

Our finding that breastfeeding and BMI were associated with prognosis only among women with luminal A-like breast cancer is consistent with those from previously published data in Western populations. Further prospective studies will be needed to clarify the role of lifestyle modification, especially changes in BMI, in improving clinical outcomes for women with luminal A-like breast cancer.

Pregnancy-associated breast cancer: maternal breast cancer survival over 10 years and obstetrical outcome at a university centre of women's health

PURPOSE

Pregnancy-associated breast cancer (PABC) is considered the second most common malignancy affecting pregnancy. The limited knowledge as to long-term survival is nonuniform. This retrospective study aims to contribute by a follow-up of pregnancies of breast cancer patients treated at a single university centre with focus on maternal long-term survival in relation to time point of diagnosis (before, during, and after pregnancy).

METHODS

Data of 25 patients were reviewed for the period between 2000 and 2009 in relation to their neonatal and maternal outcome parameters as well as their maternal breast cancer outcomes by assessing maternal mortality at annual intervals up to a maximum of 10 years follow-up.

RESULTS

Median age at diagnosis was 33 years. Maternal survival rate of the total collective came to 76% after 5 years and to 68% after 10 years. The newborns were healthy, 22% of them presented with a 1'Apgar score 5-7. Preterm delivery occurred in 53%. PABC significantly affected maternal survival compared to the national breast cancer cohort at 5 years and barely significantly at 10 years, with highly significant (p < 0.003) to significant (p < 0.01) effects at 5 and 10 years, respectively, for PABC diagnosed during and after pregnancy.

CONCLUSIONS

The present findings on survival rates suggest that maternal medical assessment at the beginning of and during further course of pregnancy should include a scrutinized thorough breast examination. Conveying/delivering special competences to monitor these high-risk pregnancies at the interface of oncological care should be considered an obligatory part of academic medical education, obstetrical training and interprofessional midwifery education.

Impact of Time Since Last Childbirth on Survival of Women with Premenopausal and Postmenopausal Breast Cancers

BACKGROUND

Reproductive factors are associated with risk of breast cancer, but the association with breast cancer survival is less well known. Previous studies have reported conflicting results on the association between time since last childbirth and breast cancer survival. We determined the association between time since last childbirth (LCB) and survival of women with premenopausal and postmenopausal breast cancers in Malaysia.

METHOD

A historical cohort of 986 premenopausal, and 1123 postmenopausal, parous breast cancer patients diagnosed from 2001 to 2012 in University Malaya Medical Centre were included in the analyses. Time since LCB was categorized into quintiles. Multivariable Cox regression was used to determine whether time since LCB was associated with survival following breast cancer, adjusting for demographic, tumor, and treatment characteristics.

RESULTS

Premenopausal breast cancer patients with the most recent childbirth (LCB quintile 1) were younger, more likely to present with unfavorable prognostic profiles and had the lowest 5-year overall survival (OS) (66.9; 95% CI 60.2-73.6%), compared to women with longer duration since LCB (quintile 2 thru 5). In univariable analysis, time since LCB was inversely associated with risk of mortality and the hazard ratio for LCB quintile 2, 3, 4, and 5 versus quintile 1 were 0.53 (95% CI 0.36-0.77), 0.49 (95% CI 0.33-0.75), 0.61 (95% CI 0.43-0.85), and 0.64 (95% CI 0.44-0.93), respectively; P _trend = 0.016. However, this association was attenuated substantially following adjustment for age at diagnosis and other prognostic factors. Similarly, postmenopausal breast cancer patients with the most recent childbirth were also more likely to present with unfavorable disease profiles. Compared to postmenopausal breast cancer patients in LCB quintile 1, patients in quintile 5 had a higher risk of mortality. This association was not significant following multivariable adjustment.

CONCLUSION

Time since LCB is not independently associated with survival in premenopausal or postmenopausal breast cancers. The apparent increase in risks of mortality in premenopausal breast cancer patients with a recent childbirth, and postmenopausal patients with longer duration since LCB, appear to be largely explained by their age at diagnosis.

Breast cancer subtype and survival by parity and time since last birth

BACKGROUND

Pregnancy affects breast cancer risk but how it affects the subtype and prognosis remain controversial. We studied the effect of parity and time since last birth on breast cancer subtype and outcome.

PATIENTS AND METHODS

We conducted a retrospective multivariate cohort study including all premenopausal women with early breast cancer aged ≤ 50 years (N = 1306) at diagnosis at the University Hospitals Leuven (Jan. 2000-Dec. 2009). Primary study endpoints were the breast cancer subtype, disease-free survival, and distant disease-free survival by parity and time since last birth. Statistical methods used were baseline-category logits models and Cox proportional hazard models. Multivariable models were used to correct for possible confounders.

RESULTS

Breast cancer subtypes did not differ between nulliparous (N = 266) and parous women (N = 1040) but subtypes differed significantly in parous women by time since last birth (p < 0.001). Tumors within 5 years of last birth were proportionally more likely triple negative and HER-2 like, even when corrected for age at diagnosis. After a mean follow-up period of 10 years, parous women had a better disease-free survival compared to nulliparous women (HR 0.733; CI 0.560-0.961; p = 0.025, HR 0.738; CI 0.559-0.974; p = 0.032 before and after correction for known prognostic factors, respectively). In parous women, a longer time since last birth was correlated with a longer disease-free survival compared to patients with a recent pregnancy (HR 0.976; CI 0.957-0.996; p = 0.018). However, after correction, this association completely disappeared (HR 1.010; CI 0.982-1.040; p = 0.480).

CONCLUSION

We observed a better disease-free survival for parous than nulliparous women. The influence of recent birth on disease-free survival is probably due to tumor and patient characteristics, as recent birth is associated with more aggressive subtypes.

Pre-diagnostic breastfeeding, adiposity, and mortality among parous Hispanic and non-Hispanic white women with invasive breast cancer: the Breast Cancer Health Disparities Study

BACKGROUND

U.S. Hispanic women have high rates of parity, breastfeeding, and obesity. It is unclear whether these reproductive factors are associated with breast cancer (BC) mortality. We examined the associations between breastfeeding, parity, adiposity and BC-specific and overall mortality in Hispanic and non-Hispanic white (NHW) BC cases.

METHODS

The study population included 2921 parous women (1477 Hispanics, 1444 NHWs) from the Breast Cancer Health Disparities Study with invasive BC diagnosed between 1995 and 2004. Information on reproductive history and lifestyle factors was collected by in-person interview. Overall and stratified Cox proportional hazard regression models by ethnicity, parity, and body mass index (BMI) at age 30 years were used to calculate hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

After a median follow-up time of 11.2 years, a total of 679 deaths occurred. Pre-diagnostic breastfeeding was associated with a 16% reduction in mortality (HR 0.84; 95% 0.72-0.99) irrespective of ethnicity. Parity significantly modified the association between breastfeeding duration and mortality (p interaction = 0.05), with longer breastfeeding duration associated with lower risk among women who had ≤2 births (p trend = 0.02). Breastfeeding duration was associated with reduced risk of both BC-specific and overall mortality among women with BMI <25 kg/m², while positive associations were observed among women with BMI ≥25 kg/m² (p interactions <0.01).

CONCLUSION

Pre-diagnostic breastfeeding was inversely associated with risk of mortality after BC, particularly in women of low parity or normal BMI. These results provide another reason to encourage breastfeeding and weight management among young women.

Breastfeeding Associated with Reduced Mortality in Women with Breast Cancer

OBJECTIVE

To study whether breastfeeding affects survival from breast cancer.

BACKGROUND

There are few studies on the relationship between breastfeeding, reproductive health, and breast cancer survival. This study is a follow-up of an earlier study showing no convincing associations between breastfeeding and breast cancer prognostic parameters.

METHODS

From a cohort of 629 women with primary breast cancer having undergone surgery between 1988 and 1992, 341 were traced and consequently studied 20 years later regarding breastfeeding and reproductive variables, as well as for prognostic parameters such as the Nottingham histological grade, tumor size, lymph node status, and vascular invasion (VI). Multivariate Cox regression analyses were used.

RESULTS

Increased breast cancer mortality was associated with the Nottingham prognostic index (hazard rate ratio (HR) 4.47; 95% confidence interval (CI) 2.04-9.79), VI (HR 3.44; CI 2.03-5.82), fewer pregnancies (three categories; >2, 1-2, 0) (HR per category 2.04; CI 1.34-3.11), and breastfeeding ≤6 months (HR 2.74; CI 1.41-5.35). The HRs for overall mortality were, as expected, lower for the Nottingham prognostic index (HR 1.28; CI 0.89-1.85) and VI (HR 2.09; CI 1.38-3.17), and they were slightly lower for the number of pregnancies (HR 1.61; CI 1.48-4.59), but notably similar for breastfeeding (HR 3.01;CI 1.92-4.73).

CONCLUSION

A total breastfeeding history >6 months and pregnancy are associated with both greater overall and breast cancer-specific survival for women diagnosed with breast cancer, having lived long enough for other causes of death to contribute substantially to mortality.

Grand multiparity and reproductive cancer in the Jerusalem Perinatal Study Cohort

OBJECTIVES

Grand multiparity is associated with reduced mortality from reproductive cancers. We aimed to separate the components of mortality, by measuring incidence of and survival after reproductive cancer onset in grand multiparous compared to other parous women.

STUDY DESIGN

We linked data from the population-based Jerusalem Perinatal Study Cohort, which included women aged 13-55 who delivered 1964-1976, with Israel's National Cancer Registry. We compared breast and gynecologic cancer risk and all-cause survival following a cancer diagnosis, among grand multiparae (GMPs = parity 5+, n = 8,246) versus women with parity 1-4 (n = 19,703), adjusting for reproductive and demographic variables.

RESULTS

Grand multiparae were at significantly lower risk of breast cancer than others (adjusted hazard ratio (HRadj) = 0.62, 95 % confidence interval (CI) 0.54-0.71), after controlling for age at first birth, education, and other covariates. This reduction was greater among GMPs whose first birth occurred after age 30 (p-interaction = 0.0001) and for cancer occurring before age 50 years (p = 0.002). In contrast, GMPs were at greater risk of death than women with parity <5, following a breast cancer diagnosis (HRadj = 1.69, CI 1.39-2.1). Ovarian, uterine, and cervical cancer incidence did not differ between the groups, but survival was reduced for GMPs with uterine cancer (HRadj = 2.48, CI 1.22-5.03).

CONCLUSION

Reduced reproductive cancer mortality reported among GMPs masks two opposing phenomena: decreased breast cancer risk and poorer survival after breast and uterine cancers. The latter unfavorable outcome suggests that tumors in GMPs may be particularly aggressive, having perhaps escaped protective mechanisms conferred by parity. This finding calls for heightened clinical attention in this group.

Adherence to Guidelines for Cancer Survivors and Health-Related Quality of Life among Korean Breast Cancer Survivors

There is limited evidence on the association between adherence to guidelines for cancer survivors and health-related quality of life (HRQoL). In a cross-sectional study of Korean breast cancer survivors, we examined whether adherence to the guidelines of the American Cancer Society (ACS) and World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) for cancer survivors was related to levels of HRQoL, assessed by the Korean version of Core 30 (C30) and Breast cancer module 23 (BR23) of the European Organization for Research and Treatment of Cancer-Quality of Life Questionnaire (EORTC-QLQ). We included a total of 160 women aged 21 to 79 years who had been diagnosed with breast cancer according to American Joint Committee on Cancer (AJCC) stages I to III and had breast cancer surgery at least six months before the interview. Increasing adherence to ACS guidelines was associated with higher scores of social functioning (p for trend = 0.05), whereas increasing adherence to WCRF/AICR recommendations was associated with higher scores of arm symptoms (p for trend = 0.01). These associations were limited to those with stage II or III cancer. Diet may be an important factor in relation to quality of life among Korean breast cancer survivors, however our findings warrant further prospective studies to evaluate whether healthy diet improves survivors’ quality of life.

Breastfeeding, PAM50 tumor subtype, and breast cancer prognosis and survival

BACKGROUND

Breastfeeding is associated with decreased breast cancer risk, yet associations with prognosis and survival by tumor subtype are largely unknown.

METHODS

We conducted a cohort study of 1636 women from two prospective breast cancer cohorts. Intrinsic tumor subtype (luminal A, luminal B, human epidermal growth factor receptor 2 [HER2]-enriched, basal-like) was determined by the PAM50 gene expression assay. Breastfeeding history was obtained from participant questionnaires. Questionnaires and medical record reviews documented 383 recurrences and 290 breast cancer deaths during a median follow-up of nine years. Multinomial logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between breastfeeding and tumor subtype. Cox regression was used to estimate hazard ratios (HRs) for breast cancer recurrence or death. Statistical significance tests were two-sided.

RESULTS

Breast cancer patients with basal-like tumors were less likely to have previously breastfed than those with luminal A tumors (OR = 0.56, 95% CI = 0.39 to 0.80). Among all patients, ever breastfeeding was associated with decreased risk of recurrence (HR = 0.70, 95% CI = 0.53 to 0.93), especially breastfeeding for six months or more (HR = 0.63, 95% CI = 0.46 to 0.87, P trend = .01). Similar associations were observed for breast cancer death. Among women with luminal A subtype, ever breastfeeding was associated with decreased risks of recurrence (HR = 0.52, 95% CI = 0.31 to 0.89) and breast cancer death (HR = 0.52, 95% CI = 0.29 to 0.93), yet no statistically significant associations were observed among the other subtypes. Effects appeared to be limited to tumors with lower expression of proliferation genes.

CONCLUSIONS

History of breastfeeding might affect prognosis and survival by establishing a luminal tumor environment with lower proliferative activity.

Tumor subtype-specific associations of hormone-related reproductive factors on breast cancer survival

PURPOSE

It is inconclusive whether reproductive factors, which are known as risk factors of breast cancer, also influence survival. We investigated overall and subtype-specific associations between reproductive factors and breast cancer survival.

METHODS

Among 3,430 incident breast cancer patients who enrolled in the Seoul Breast Cancer Study, 269 patients (7.8%) died and 528 patients (15.4%) recurred. The overall and subtype-specific associations of reproductive factors including age at menarche and menopause, duration of estrogen exposure, menstrual cycle, parity, age at first full-term pregnancy, number of children, age at last birth, time since the last birth, and duration of breastfeeding, on overall and disease-free survival (OS and DFS) were estimated by hazard ratios (HRs) and 95% confidence intervals (95% CIs) using a multivariate Cox proportional hazard model.

RESULTS

An older age at menarche (HR for OS=1.10, 95% CI=1.03-1.19), a greater number of children (≥ 4 vs. 2, HR for DFS=1.58, 95% CI=1.11-2.26), and a shorter time since last birth (<5 vs. ≥ 20 years, HR for DFS=1.67, 95% CI=1.07-2.62) were associated with worse survival while longer duration of estrogen exposure with better survival (HR for DFS=0.97, 95% CI=0.96-0.99). In the stratified analyses by subtypes, those associations were more pronounced among women with hormone receptor and human epidermal growth factor 2 positive (HR+ HER2+) tumors.

CONCLUSIONS

It is suggested that reproductive factors, specifically age at menarche, number of children, time since last birth, and duration of estrogen exposure, could influence breast tumor progression, especially in the HR+ HER2+ subtype.

Excessive milk production during breast-feeding prior to breast cancer diagnosis is associated with increased risk for early events

Breast-feeding is a known protective factor against breast cancer. Breast-feeding duration is influenced by hormone levels, milk production, and lifestyle factors. The aims were to investigate how breast-feeding duration and milk production affected tumor characteristics and risk for early breast cancer events in primary breast cancer patients. Between 2002 and 2008, 634 breast cancer patients in Lund, Sweden, took part in an ongoing prospective cohort study. Data were extracted from questionnaires, pathology reports, and patients’ charts from 592 patients without preoperative treatment. Breast-feeding duration ≤12 months of the first child was associated with higher frequency of ER+/PgR+ tumors (P=0.02). Median follow-up time was 4.9 years. Higher risk for early events was observed for breast-feeding duration of first child >12 months (LogRank P=0.001), total breast-feeding duration >12 months (LogRank P=0.008), as well as ‘excessive milk production’ during breast-feeding of the first child (LogRank P=0.001). Patients with ‘almost no milk production’ had no events. In a multivariable model including both ‘excessive milk production’ and breast-feeding duration of the first child >12 months, both were associated with a two-fold risk for early events, adjusted HRs 2.33 (95% CI: 1.25-4.36) and 2.39 (0.97-5.85), respectively, while total breast-feeding duration was not. ‘Excessive milk production’ was associated with a two-fold risk of early distant metastases, adjusted HR 2.59 (1.13-5.94), but not duration. In conclusion, ‘excessive milk production’ during breast-feeding was associated with higher risk for early events independent of tumor characteristics, stressing the need to consider host factors in the evaluation of prognostic markers.

Impact of recent parity on histopathological tumor features and breast cancer outcome in premenopausal Japanese women

Although previous studies have reported that onset at young age is associated with poor prognosis in breast cancer, the correlation between reproductive factors, breast cancer characteristics, and prognosis remains unclear. Five hundred and twenty-six premenopausal young women diagnosed with primary invasive breast cancer between January 2000 and December 2007 were included in this study. Patients were classified into four groups according to their reproductive history: women who gave birth within the previous 2 years (group A), women who gave birth between 3 and 5 years previously (group B), women who gave birth more than 5 years previously (group C), and nulliparous women (group N). The correlation between the time since last childbirth to diagnosis, histopathological tumor features, and breast cancer prognosis was evaluated. Breast cancer patients who had given birth more recently had more advanced stage tumors; larger sized tumors; a higher rate of axillary lymph node metastases; a higher histological tumor grade; and increased progesterone receptor (PgR)-, HER2+, and triple negative tumors than patients who had given birth less recently or not at all. Group A patients had significantly shorter survival times than patients in both groups C and N (log rank test; p < 0.001). After adjusting for tumor characteristics, the hazard ratio for death in group A was 2.19 compared with group N (p = 0.036), and the adjusted hazard ratio restricted to patients in group A with hormone-receptor-positive, and HER2- tumors was 3.07 (p = 0.011). Young breast cancer patients who had given birth more recently had tumors with more aggressive features and worse prognoses compared with patients who had given birth less recently or were nulliparous.

Association of time since last birth, age at first birth and parity with breast cancer survival among parous women: a register-based study from Norway

Reproductive factors that have a well-documented effect on breast cancer risk may also influence the prognosis of the disease, but previous studies on breast cancer survival have yielded conflicting results. We combined information from two population-based registries and obtained information on 16,970 parous women with invasive breast cancer. Cox regression analysis was used to assess breast cancer survival in relation to age at diagnosis, age at first birth, time since last birth and parity. We stratified the analyses by age at diagnosis (<50 and ≥ 50 years) as an approximation for menopausal age. In women diagnosed before 50 years of age, breast cancer survival was reduced with younger age at diagnosis (p for trend <0.001), whereas in women diagnosed at 50 years or later, survival was reduced with older age at diagnosis (p for trend 0.011). For breast cancer diagnosed before 50 years, survival was poorer in women with four or more births compared to women with one or two births (hazard ratio 1.3, 95% confidence interval 1.1-1.6). A short time since last birth was associated with reduced survival (p for trend 0.05), but adjustment for stage and grade attenuated the association. Among women diagnosed at 50 years or later, we found no association with survival for any of the reproductive factors. In summary, reproductive factors were associated with survival from breast cancer diagnosed before but not after age 50 years. Young women had a particularly poor prognosis throughout the study period.

Reproductive factors and histologic subtype in relation to mortality after a breast cancer diagnosis

Evidence suggests that certain reproductive factors are more strongly associated with the incidence of lobular than of ductal breast cancer. The mechanisms influencing breast cancer incidence histology may also affect survival. Women with invasive breast cancer (N = 22,302) diagnosed during 1986-2005 were enrolled in a series of population-based studies in three US states. Participants completed telephone interviews regarding reproductive exposures and other breast cancer risk factors. Histologic subtype was obtained from state cancer registries. Vital status and cause of death were determined through December 2006 using the National Death Index. Women were followed for 9.8 years on average with 3,050 breast cancer deaths documented. Adjusted hazard rate ratios (HR) and 95% confidence intervals (95% CI) were calculated using Cox proportional hazards regression models for breast cancer-specific and all-cause mortality. Parity was inversely associated with breast cancer-specific mortality (P (Trend) = 0.002). Associations were similar though attenuated for all-cause mortality. In women diagnosed with ductal breast cancer, a 15% reduction in breast cancer-specific mortality was observed in women with five or more children when compared to those with no children (HR = 0.85, 95% CI: 0.73-1.00). A similar inverse though non-significant association was observed in women with lobular subtype (HR = 0.70, 95% CI: 0.43-1.14). The trend did not extend to mixed ductal-lobular breast cancer. Age at first birth had no consistent relationship with breast cancer-specific or all-cause mortality. We found increasing parity reduced mortality in ductal and lobular breast cancer. The number of full-term births, rather than age at first birth, has an effect on both breast cancer-specific and overall mortality.

Early age at menarche associated with cardiovascular disease and mortality

CONTEXT

The relationship between age at menarche and cardiovascular disease remains unclear. Two recent studies found an inverse association between age at menarche and all-cause mortality.

OBJECTIVE

The aim of this study was to examine the relationship between age at menarche and cardiovascular disease risk factors, events, and mortality.

DESIGN, SETTING, AND PARTICIPANTS

A population-based prospective study involving 15,807 women, aged 40-79 yr in 1993-1997 and followed up to March 2007 for cardiovascular disease events (median follow-up 10.6 yr) and February 2008 for mortality (median follow-up 12.0 yr) was used.

MAIN OUTCOME MEASURES

Odds ratios for cardiovascular disease risk factors and hazard ratios for incident cardiovascular disease and mortality were calculated.

RESULTS

There were 3888 incident cardiovascular disease events (1323 coronary heart disease, 602 stroke, and 1963 other) and 1903 deaths (640 cardiovascular disease, 782 cancer, and 481 other) during follow-up. Compared with other women, those who had early menarche (<12 yr) had higher risks of hypertension [1.13 (1.02-1.24)], incident cardiovascular disease [1.17 (1.07-1.27)], incident coronary heart disease [1.23 (1.06-1.43)], all-cause mortality [1.22 (1.07-1.39)], cardiovascular disease mortality [1.28 (1.02-1.62)], and cancer mortality [1.25 (1.03-1.51)], adjusted for age, physical activity, smoking, alcohol, educational level, occupational social class, oral contraceptive use, hormone replacement therapy, parity, body mass index, and waist circumference.

CONCLUSIONS

Early age at menarche (before age 12 yr) was associated with increased risk of cardiovascular disease events, cardiovascular disease mortality, and overall mortality in women, and this association appeared to be only partly mediated by increased adiposity.

Parity and age at first childbirth in relation to the risk of different breast cancer subgroups

The aim of the present study was to examine parity and age at first childbirth, in relation to the risk of specific breast cancer subgroups. A prospective cohort, The Malmö Diet and Cancer Study, including 17,035 women were followed with linkage to Swedish Cancer Registry until December 31, 2004. A total of 622 incident breast cancers were diagnosed during follow-up and were evaluated regarding invasiveness, tumour size, axillary lymph node status, Nottingham grade, tumour proliferation (Ki67), HER2, cyclin D1 and p27. The tumours were also examined for WHO type and hormone receptor status. Nulliparity was associated with an overall increased risk of breast cancer, although not statistically significant (the relative risk was 1.39 with a 95% confidence interval of 0.92-2.08). Nulliparity was also associated with large tumours (>20 mm) (1.89: 0.91-3.91), high Ki67 levels (1.95: 0.93-4.10), high cyclin D1 levels (2.15: 0.88-5.27), grade III (2.93: 1.29-6.64) and HER2 positive tumours (3.24: 1.02-10.25). High parity was not statistically significantly associated with any specific breast cancer subgroup. Older age at first childbirth (>30) was associated with a slightly increased risk of breast cancer (1.39: 0.94-2.07). There was a statistically significant association between late first childbirth and lobular type (2.51: 1.01-6.28), grade III tumours (2.67: 1.19-6.02), high levels of cyclin D1 (2.69: 1.18-6.12) and low levels of p27 (2.23: 1.15-4.35). We conclude that nulliparity and late first childbirth are associated with relatively more aggressive breast cancer subgroups.

Prediagnosis reproductive factors and all-cause mortality for women with breast cancer in the breast cancer family registry

Studies have examined the prognostic relevance of reproductive factors before breast cancer diagnosis, but most have been small and their overall findings inconclusive. Associations between reproductive risk factors and all-cause mortality after breast cancer diagnosis were assessed with the use of a population-based cohort of 3,107 women of White European ancestry with invasive breast cancer (1,130 from Melbourne and Sydney, Australia; 1,441 from Ontario, Canada; and 536 from Northern California, United States). During follow-up with a median of 8.5 years, 567 deaths occurred. At recruitment, questionnaire data were collected on oral contraceptive use, number of full-term pregnancies, age at first full-term pregnancy, time from last full-term pregnancy to breast cancer diagnosis, breastfeeding, age at menarche, and menopause and menopausal status at breast cancer diagnosis. Hazard ratios for all-cause mortality were estimated with the use of Cox proportional hazards models with and without adjustment for age at diagnosis, study center, education, and body mass index. Compared with nulliparous women, those who had a child up to 2 years, or between 2 and 5 years, before their breast cancer diagnosis were more likely to die. The unadjusted hazard ratio estimates were 2.75 [95% confidence interval (95% CI), 1.98-3.83; P < 0.001] and 2.20 (95% CI, 1.65-2.94; P < 0.001), respectively, and the adjusted estimates were 2.25 (95% CI, 1.59-3.18; P < 0.001) and 1.82 (95% CI, 1.35-2.46; P < 0.001), respectively. When evaluating the prognosis of women recently diagnosed with breast cancer, the time since last full-term pregnancy should be routinely considered along with other established host and tumor prognostic factors, but consideration of other reproductive factors may not be warranted.

The epidemiology of triple-negative breast cancer, including race

OBJECTIVE

Predictors of intrinsic breast cancer subtypes, including the triple-negative (TN) subtype, are largely unknown. We evaluated whether anthropometrics, demographics, and reproductive history were associated with distinct breast cancer subtypes.

METHODS

Invasive breast tumors from a population-based case-control study of 476 (116 black and 360 white) Atlanta women aged 20-54, diagnosed between 1990 and 1992, were centrally reviewed and immunohistochemically analyzed for estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2); then grouped [TN (ER-PR-HER2-); ER-PR-HER2+; ER/PR+HER2+; ER/PR+HER2- (case-only reference group)]. Data were from interviews and anthropometric measurements; adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression, including both case-only and case-control comparisons.

RESULTS

From the case-only analyses and compared with the ER/PR+HER2- subtype, women with TN tumors were more likely to be obese than normal/underweight [OR = 1.89 (95% CI = 1.22, 2.92)]. Regardless of HER2 status, ER-PR- tumors were associated with black race, young age at first birth, having a recent birth, and being overweight.

CONCLUSIONS

Distinct breast cancer subtypes have unique sociodemographic, anthropometric and reproductive characteristics and possibly different pathways for development.

Placental weight and breast cancer survival in young women

A growing body of evidence indicates that reproductive history influences survival in breast cancer, especially among women diagnosed during or shortly after a pregnancy. However, little is known about the underlying mechanisms. We hypothesized that increasing placental weight, as an indirect marker of exposure to elevated hormone levels during pregnancy, would be associated with reduced survival in breast cancer. A cohort of 1873 women with at least one pregnancy after January 1st, 1973, and a subsequent breast cancer diagnosis before the end of 1991 were followed up for death or emigration through 2006. Information on placental weight and potential confounding factors were collected from medical records and from nationwide registers, which resulted in data on placental weight in the most recent pregnancy before diagnosis for 1,057 cases. For each 100-gram increase in placental weight, the adjusted hazard ratio of death was 1.09 [95% confidence interval (CI), 0.99-1.19]. The association was stronger among primiparous women (adjusted hazard ratio, 1.26; 95% CI, 1.09-1.47), and among women diagnosed during pregnancy or within 2 years from last birth (adjusted hazard ratio, 1.30; 95% CI, 1.06-1.59). Increasing placental weight is associated with reduced breast cancer survival. These findings are consistent with the hypothesis that the reduced survival in breast cancer among women with a recent childbirth is linked to pregnancy hormone exposure.

The influence of menstrual risk factors on tumor characteristics and survival in postmenopausal breast cancer

Introduction

Hormonal factors are implicated in tumor progression and it is possible that factors influencing breast cancer induction could affect prognosis. Our study investigated the effects of menstrual risk factors on tumor characteristics and survival in postmenopausal breast cancer.

Methods

We used a nationwide, population-based, case-case design of 2,640 Swedish women who were 50 to 74 years old and had postmenopausal breast cancer during 1993 to 1995. Follow-up was conducted until 31 December 2000. We used polytomous multiple logistic regression to investigate the relationships between menstrual factors (age at menarche, cycle length, irregular menstruation, lifetime number of menstrual cycles, and age at menopause), tumor characteristics (size, grade, estrogen receptor and progesterone receptor [PR] status, lymph node involvement, and histology), and Cox proportional hazards modeling for 5-year survival.

Results

Younger ages at menarche were significantly associated with grade and lymph node involvement. Women with an age at menarche of 11 years or younger had a more than twofold excess risk of medium-grade (odds ratio [OR] = 2.05; 95% confidence interval [CI] 1.00 to 4.18) and high-grade (OR = 2.04; 95% CI 1.01 to 4.16) tumors. Early menarche significantly increased the risk of lymph node metastases. Survival was poorest in women with the earliest age at menarche, with a 72% increased risk of dying within 5 years after diagnosis (hazard ratio = 1.72; 95% CI 1.02 to 2.89). No significant associations were observed for other menstrual factors with tumor characteristics or survival.

Conclusions

Age at menarche has a significant impact on breast cancer prognosis and survival. It remains to be established whether the associations are attributable to age at menarche directly or are associated with the early-life physiological events of breast development and carcinogenesis also taking place during childhood and puberty, as menarche is only the culmination of this series of events.

High prevalence of triple-negative tumors in an urban cancer center

BACKGROUND

A disparate proportion of breast cancer deaths occur among young women, those of African-American (AA) ancestry, and particularly young AA women. Estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptor-2 (HER-2) are key clinically informative biomarkers. The triple-negative (ER-/PR-/HER-2-) tumor subgroup is intrinsically resistant to treatment and portends a poor prognosis. Age, race, and socioeconomic status have been associated with triple-negative tumors (TNT). In the current study, the authors investigated breast cancer subgroups among patients in an urban cancer center serving a multiracial, low socioeconomic population.

METHODS

This case series analyzed female invasive breast cancers diagnosed and/or treated between 2003 and 2004 in the AVON Comprehensive Breast Center at Grady Hospital in Atlanta, Georgia. Data were obtained from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program, and augmented by the hospital registry and pathology reports. Statistical analyses utilized frequency distributions and logistic regression.

RESULTS

Of 190 breast cancers; 167 (88%) were diagnosed among AA and 23 (12%) were diagnosed among non-AA women. The median age at diagnosis in the 2 groups was 58 years and 57 years, respectively. TNT prevalence was found to differ by race (29.3% among AA women and 13.0% among non-AA women; P = .010). Differences persisted after adjustment for age and stage (odds ratio [OR] of 3.1; 95%confidence interval [95% CI], 0.8-11.6). The majority of recurrences (40.0%) occurred among women with TNT, who were also most likely to experience a fatal event (OR of 3.7; 95%CI, 1.1-13.0).

CONCLUSIONS

Despite a similarity in their age at diagnosis, AA women in our urban cancer center presented with a higher prevalence of TNT and TNT was found to predict the poorest outcomes. Institutional interactive breast conferences and intervention/navigation programs could help to dispel breast cancer disparities and improve outcomes.

Relationship of time since childbirth and other pregnancy factors to premenopausal breast cancer prognosis

OBJECTIVE

To investigate the influence of time since childbirth and other pregnancy factors on the prognosis of premenopausal breast cancer.

METHODS

Women who delivered an infant in Nova Scotia, Canada, between 1980 and 2001 were identified from a provincial perinatal database and linked to the Nova Scotia Cancer Registry to determine primary breast cancer diagnoses among women aged younger than 50 years. Relative risks and Cox proportional hazards ratios were calculated to quantify the relationship of time from childbirth to diagnosis and other pregnancy factors to the extent of disease at diagnosis and on survival after breast cancer diagnosis.

RESULTS

Of the 123,323 women who delivered an infant during the study period, 716 women were diagnosed with invasive breast cancer. Women with less than 5 years between their last delivery and diagnosis were more likely to be diagnosed with later-stage disease and had poorer survival even after adjusting for stage of disease (less than 2 years, adjusted hazards ratio 2.1, 95% confidence interval 1.2-3.9; 2-4 years, hazards ratio 1.6, 95% confidence interval 0.9-2.8) compared with women with 5 years or more. For every 13 women with less than 2 years between delivery and diagnosis, one excess death will occur, compared with women with 5 or more years between delivery and diagnosis.

CONCLUSION

A time interval of less than 2 years (and 2-4 years) between childbirth and breast cancer diagnosis worsens the prognosis in a dose-response fashion. Clinicians should be aware of these findings when examining women in the first 5 years after a delivery.

LEVEL OF EVIDENCE

II.

Parity in relation to survival following breast cancer

AIM

The present study examines the association between parity and survival following breast cancer diagnosis.

METHODS

Medical records of 4453 women diagnosed with breast cancer in Malmö, Sweden, between 1961 and 1991 were analysed. All women were followed until 31 December 2003, using the Swedish Cause-of-Death Registry. Breast cancer specific mortality rate was calculated in different levels of parity. Corresponding relative risks, with 95% confidence intervals (CI), were obtained using Cox's proportional hazards analysis. All analyses were adjusted for potential prognostic factors and stratified for age, menopausal status and diagnostic period.

RESULTS

As compared to women with one child, nulliparity (RR 1.27: 95% CI 1.09-1.47), and high parity (four or more children) (1.49: 1.20-1.85) were positively associated with a high mortality from breast cancer. When adjusted for potential confounders, the association was only statistically significant for high parity (1.33: 1.07-1.66). In the analyses stratified on age and menopausal status, there was a similar positive association between high parity and breast cancer death in all strata, although only statistically significant among women older than 45 years of age or postmenopausal. Nulliparity was associated with breast cancer death in women that were younger than 45 years of age (1.28: 0.79-2.09) or premenopausal (1.30: 0.95-1.80), but these associations did not reach statistical significance. There was no association between nulliparity and breast cancer death in women older than 45 years of age or postmenopausal. All associations were similar in analyses stratified for diagnostic period.

CONCLUSION

Women with four or more children have a poor breast cancer survival as compared to women with one child.