Issues in breast cancer prevention: body mass index, breast density, and fractures

Breast cancer is the most frequently diagnosed cancer besides skin and the second leading cause of cancer death among American women. Breast cancer prevention comprises all techniques that lower the risk for developing breast cancer, thereby lowering population incidence and mortality. This dissertation used breast cancer prevention clinical trials data from the National Surgical Adjuvant Breast and Bowel Project to evaluate important issues related to breast cancer prevention. Some breast cancer risk factors are modifiable and can be changed with lifestyle adjustments. For example, high body weight has been associated with increased breast cancer risk among postmenopausal women, but the relationship in premenopausal women has remained unclear. In the first analysis, we found a significant association between overweight and obesity and increased breast cancer risk in premenopausal women, and a nonsignificant association among postmenopausal women. Other risk factors are not modifiable and require more complex interventions such as chemopreventive therapies. The Gail model is the most popular risk prediction model to determine who might benefit from these therapies, but it does not include breast density which is an established breast cancer risk factor. In a second analysis, high breast density was significantly associated with increased breast cancer risk when considered with the Gail score, but provided only slight improvement in discriminatory accuracy. Despite the success and availability of tamoxifen and raloxifene as chemopreventive agents, they have been underused in clinical settings. Providing more information about these drugs may help to increase their popularity. A final analysis expanded on prior findings about tamoxifen and bone fractures, and showed that tamoxifen reduced osteoporotic fracture risk for all subgroups of women. The public health significance of this dissertation is realized in the clarification and expansion of knowledge surrounding important issues in breast cancer prevention for both clinicians and patients. We showed that maintaining a healthy weight is likely beneficial for all women at high-risk for developing breast cancer, and that women receiving tamoxifen will gain the added benefit of fracture risk reduction. Furthermore, among postmenopausal women, a single assessment of breast density does not provide substantial risk prediction improvement

25-Hydroxy vitamin-D, obesity, and associated variables as predictors of breast cancer risk and tamoxifen benefit in NSABP-P1.

Observational studies suggest that host factors are associated with breast cancer risk. The influence of obesity, vitamin-D status, insulin resistance, inflammation, and elevated adipocytokines in women at high risk of breast cancer is unknown. The NSABP-P1 trial population was used for a nested case-control study. Cases were drawn from those who developed invasive breast cancer and controls selected from unaffected participants (≤4 per case) matched for age, race, 5 year Gail score, and geographic location of clinical center as a surrogate for latitude. Fasting serum banked at trial enrolment was assayed for 25-hydroxy vitamin-D (25OHD), insulin, leptin (adipocytokine), and C-reactive protein (CRP, marker of inflammation). Logistic regression was used to test for associations between study variables and the risk of invasive breast cancer. Two hundred and thirty-one cases were matched with 856 controls. Mean age was 54, and 49% were premenopausal. There were negative correlations for 25OHD with body mass index (BMI), insulin, CRP, and leptin. BMI ≥ 25 kg/m(2) was associated with higher breast cancer risk (odds ratio [OR] 1.45, p = 0.02) and tamoxifen treatment was associated with lower risk (OR = 0.44, p < 0.001). Suboptimal 25OHD (<72 nmol/l) did not influence breast cancer risk (OR = 1.06, p = 0.76). When evaluated as continuous variables, 25OHD, insulin, CRP, and leptin levels were not associated with breast cancer risk (all p > 0.34). In this high risk population, higher BMI was associated with a greater breast cancer risk. Serum levels of 25OHD, insulin, CRP, and leptin were not independent predictors of either breast cancer risk or tamoxifen benefit

Long-Term Follow-Up of Cardiac Function and Quality of Life for Patients in NSABP Protocol B-31/NRG Oncology: A Randomized Trial Comparing the Safety and Efficacy of Doxorubicin and Cyclophosphamide (AC) Followed by Paclitaxel With AC Followed by Paclitaxel and Trastuzumab in Patients With Node-Positive Breast Cancer With Tumors Overexpressing Human Epidermal Growth Factor Receptor 2

Purpose Early cardiac toxicity is a risk associated with adjuvant chemotherapy plus trastuzumab. However, objective measures of cardiac function and health-related quality of life are lacking in long-term follow-up of patients who remain cancer free after completion of adjuvant treatment. Patients and Methods Patients in NSABP Protocol B-31 received anthracycline and taxane chemotherapy with or without trastuzumab for adjuvant treatment of node-positive, human epidermal growth factor receptor 2–positive early-stage breast cancer. A long-term follow-up assessment was undertaken for patients who were alive and disease free, which included measurement of left ventricular ejection fraction by multigated acquisition scan along with patient-reported outcomes using the Duke Activity Status Index (DASI), the Medical Outcomes Study questionnaire, and a review of current medications and comorbid conditions. Results At a median follow-up of 8.8 years among eligible participants, five (4.5%) of 110 in the control group and 10 (3.4%) of 297 in the trastuzumab group had a \u3e 10% decline in left ventricular ejection fraction from baseline to a value \u3c 50%. Lower DASI scores correlated with age and use of medications for hypertension, cardiac conditions, diabetes, and hyperlipidemia, but not with whether patients had received trastuzumab. Conclusion In patients without underlying cardiac disease at baseline, the addition of trastuzumab to adjuvant anthracycline and taxane-based chemotherapy does not result in long-term worsening of cardiac function, cardiac symptoms, or health-related quality of life. The DASI questionnaire may provide a simple and useful tool for monitoring patient-reported changes that reflect cardiac function

25-Hydroxy vitamin-D, obesity, and associated variables as predictors of breast cancer risk and tamoxifen benefit in NSABP-P1.

Observational studies suggest that host factors are associated with breast cancer risk. The influence of obesity, vitamin-D status, insulin resistance, inflammation, and elevated adipocytokines in women at high risk of breast cancer is unknown. The NSABP-P1 trial population was used for a nested case-control study. Cases were drawn from those who developed invasive breast cancer and controls selected from unaffected participants (≤4 per case) matched for age, race, 5 year Gail score, and geographic location of clinical center as a surrogate for latitude. Fasting serum banked at trial enrolment was assayed for 25-hydroxy vitamin-D (25OHD), insulin, leptin (adipocytokine), and C-reactive protein (CRP, marker of inflammation). Logistic regression was used to test for associations between study variables and the risk of invasive breast cancer. Two hundred and thirty-one cases were matched with 856 controls. Mean age was 54, and 49% were premenopausal. There were negative correlations for 25OHD with body mass index (BMI), insulin, CRP, and leptin. BMI ≥ 25 kg/m(2) was associated with higher breast cancer risk (odds ratio [OR] 1.45, p = 0.02) and tamoxifen treatment was associated with lower risk (OR = 0.44, p < 0.001). Suboptimal 25OHD (<72 nmol/l) did not influence breast cancer risk (OR = 1.06, p = 0.76). When evaluated as continuous variables, 25OHD, insulin, CRP, and leptin levels were not associated with breast cancer risk (all p > 0.34). In this high risk population, higher BMI was associated with a greater breast cancer risk. Serum levels of 25OHD, insulin, CRP, and leptin were not independent predictors of either breast cancer risk or tamoxifen benefit

Erratum to: 25-Hydroxy vitamin-D, obesity, and associated variables as predictors of breast cancer risk and tamoxifen benefit in NSABP-P1

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Recruitment practices for U.S. minority and underserved populations in NRG oncology: Results of an online survey

Introduction: Cancer clinical trials (CCT) provide much of the evidence for clinical guidelines and standards of care. But low levels of CCT participation are well documented, especially for minorities. Methods and materials: We conducted an online survey of 556 recruitment practices across the NRG Oncology network. Survey aims were 1) to learn how sites recruit minority/underserved populations; 2) to better understand the catchment areas of the NRG institutions; and 3) to aid in planning education programs for accrual of minority/underserved populations. Results: The survey response rate was 34.9%. The most effective methods reported for recruiting minority/underserved participants were patient navigators (44.4%) and translators (38.9%). All institutions reported using a mechanism for eligibility screening and 71% of institutions reported using a screening/enrollment tracking system. CCT training was required at 78.1% and cultural competency training was required at 47.5% of responding institutions. Only 19.9% of sites used community partners to assist with minority recruitment and just 37.1% of respondents reported a defined catchment area. Sites reported very little race and ethnicity data. Conclusion: This NRG Oncology online survey provides useful data for improvements in trial enrollment and training to recruit minority/underserved populations to CCT. Areas for further investigation include web-based methods for recruitment and tracking, cultural competency training, definition of catchment areas, use of patient navigators, and community partnerships. The survey results will guide recruitment training programs

Toxicity Index, Patient-Reported Outcomes, and Early Discontinuation of Endocrine Therapy for Breast Cancer Risk Reduction in NRG Oncology/NSABP B-35.

PurposeThe US National Cancer Institute Moonshot initiative calls for improving analysis and reporting of toxicity to inform treatment tolerability. We used existing clinician-reported adverse event (AE) and patient-reported outcome (PRO) questionnaire data from the randomized, double-blind NSABP B-35 clinical trial to explore reasons for anastrozole and tamoxifen discontinuation.MethodsPostmenopausal women with ductal carcinoma in situ treated with breast-conserving therapy were randomly assigned to anastrozole or tamoxifen for 5 years. The primary outcome for this analysis was time to treatment discontinuation. AEs were collected every 6 months post-random assignment from all 3,104 participants and summarized using the Toxicity Index (TI). PRO data were collected at baseline and every 6 months from 1,194 participants. Univariate and multivariable analyses of time to treatment discontinuation were performed using Cox regression models with TIs and PROs as time-dependent covariates.ResultsOf 3,046 analyzed participants, 869 (28.5%) discontinued treatment prematurely. In multivariable analysis, when both baseline PROs and on-treatment AEs were considered, thrombosis and arthralgia AEs were associated with discontinuation of both tamoxifen and anastrozole; additional AEs associated with discontinuation varied by drug. In addition, baseline pain interference, hot flashes, and unhappiness were associated with tamoxifen discontinuation (n = 589; overall Harrell's C-statistic 0.686 [95% CI, 0.640 to 0.732]); no baseline PROs were associated with anastrozole discontinuation (n = 589; overall Harrell's C-statistic 0.656 [95% CI, 0.630 to 0.681]). When only baseline PROs were examined, pain interference, hot flashes, and unhappiness were associated with shorter time to discontinuation of tamoxifen; only hot flashes were associated with discontinuation of anastrozole.ConclusionAnalysis of AEs using the TI yielded important insights into reasons for discontinuation of endocrine therapy that was enhanced by the addition of PRO baseline and treatment-emergent symptoms

Toxicity Index, patient-reported outcomes, and persistence of breast cancer chemotherapy-associated side effects in NRG Oncology/NSABP B-30

Adjuvant chemotherapy improves breast cancer survival but is associated with bothersome short- and long-term toxicity. Factors associated with toxicity, especially subacute toxicity up to 2 years following chemotherapy, have not been fully elucidated. The NRG Oncology/NSABP B-30 clinical trial compared 3 different doxorubicin-, cyclophosphamide-, and docetaxel-based chemotherapy regimens given over 3-6 months. Patients with hormone receptor-positive breast cancer received subsequent adjuvant endocrine therapy. From baseline through 24 months, 2156 patients completed questionnaires serially. We used multivariable probabilistic index models to identify factors associated with acute (>0-12 months) and subacute (>12-24 months) difficulties with pain, cognition, vasomotor symptoms, and vaginal symptoms. For all symptom domains, presence of symptoms prior to chemotherapy initiation were associated with symptoms in the subacute period (all p < 0.001). In addition, different combinations of patient factors and breast cancer treatments were associated with increased likelihood of pain, vasomotor, and vaginal symptoms in the subacute period. Consideration of pre-treatment symptoms and patient factors, as well as treatments for breast cancer, can facilitate identification of groups of patients that may experience symptoms following completion of chemotherapy. This information may be important for treatment-decision-making when alternative regimens are equivalent in benefit