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Biomedical subjects

Rowan T Chlebowski

Publications and source records attributed to Rowan T Chlebowski.

At least 37 records · Page 2Linked to original sources
PubMed2005

Abnormal mammographic findings with short-interval follow-up recommendation.

An abnormal Breast Imaging and Reporting Data System (BIRADS) category 3 mammogram with a short interval follow-up recommendation is a common finding seen in approximately 40% of women for each decade of screening. Factors associated with category 3 mammograms include mammography examination features, tendencies of the interpreting physician, and features of the country's health care system and the screened population including age, family history, previous biopsies, obesity, and menopausal hormone therapy. Recently, the degree to which a BIRADS category 3 mammographic result provides differential breast cancer risk compared with normal mammographic categories (BIRADS category 1 or 2) has been questioned. The yield of category 3 mammographic results could potentially be increased by more uniform performance of additional imaging workup (additional views and/or ultrasonography). In addition, other strategies to more accurately characterize the risk of breast cancer in women with category 3 mammographic results are under evaluation and including magnetic resonance imaging, computer-aided classification systems, and digital tomosynthesis. Given the potential psychologic impact of abnormal mammographic results, studies attempting to more accurately relate screening mammography findings to breast cancer risk are a priority.

Breast Diseases↗
PubMed2005

Bone health in women with early-stage breast cancer.

Bone health is an increasingly important concern in breast cancer survivors because in postmenopausal women, bone-sparing tamoxifen is being replaced by aromatase inhibitors, whereas in premenopausal women, ovarian suppression is playing an increasing role in adjuvant management. Estrogen reduction resulting from aromatase inhibition and ovarian suppression are associated with loss in bone mineral density (BMD) and an increase in fracture risk. These side effects must be placed in context of the overall risks and benefits seen with these interventions. The American Society of Clinical Oncology has outlined a management strategy for bone health maintenance in breast cancer survivors with early-stage disease that incorporates baseline and ongoing screening for BMD and treatment based on BMD results. Limited but consistent data suggest bisphosphonate therapy represents a treatment option for this condition. A variety of interventions to maintain bone health in breast cancer survivors are undergoing clinical evaluation and include the oral bisphosphonates risedronate and clodronate, the intravenous bisphosphonate zoledronic acid, the receptor activator of nuclear factor-kB ligand inhibitor AMG-162, and the hormonal agent tibolone. Current information suggests bone loss associated with estrogen reduction in breast cancer survivors may represent a preventable and treatable condition. Ongoing clinical trials will definitively evaluate this hypothesis.

Antineoplastic Agents↗
PubMed2004

Insulin, physical activity, and caloric intake in postmenopausal women: breast cancer implications.

PURPOSE: Increased physical activity and programs to reduce body mass index (BMI) with both increased physical activity and decreased caloric intake have been proposed to reduce insulin as a potential mediator of breast cancer and other chronic diseases. However, there are few data on the relative contribution of physical activity, caloric intake, and BMI to fasting insulin levels. MATERIALS AND METHODS: An ethnically diverse subsample of 2,996 mostly healthy postmenopausal women with no prior cancer history was randomly identified from the 161,809 participants in the Women's Health Initiative clinical trials and observational study. Information was collected on diet, recreational physical activity, and anthropometrics including BMI. Fasting insulin levels were determined. Using a cross-sectional design, insulin levels were then compared across quintiles of caloric intake and physical activity in linear regression model analyses controlled for BMI and other factors. RESULTS: Lower BMI (P < .0001), higher levels of physical activity (P < .0001), and lower caloric intake (P < .02) were all independently associated with significantly lower mean fasting insulin levels throughout the range of observed values. Insulin levels of 8.74 microU/mL +/- 4.16 SD were seen in the highest physical activity and lowest caloric intake quintile compared with insulin levels of 15.08 microU/mL +/- 16.32 SD in the lowest physical activity and highest caloric intake quintile (P < .0001). CONCLUSION: These findings suggest that reduction in BMI achieved by increasing physical activity, reducing caloric intake, or both, should lower insulin levels, providing support for clinical trials evaluating insulin level change and breast cancer risk.

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PubMed2004

American Society of Clinical Oncology technology assessment on the use of aromatase inhibitors as adjuvant therapy for postmenopausal women with hormone receptor-positive breast cancer: status report 2004.

PURPOSE: To update the 2003 American Society of Clinical Oncology technology assessment on adjuvant use of aromatase inhibitors. RECOMMENDATIONS: Based on results from multiple large randomized trials, adjuvant therapy for postmenopausal women with hormone receptor-positive breast cancer should include an aromatase inhibitor in order to lower the risk of tumor recurrence. Neither the optimal timing nor duration of aromatase inhibitor therapy is established. Aromatase inhibitors are appropriate as initial treatment for women with contraindications to tamoxifen. For all other postmenopausal women, treatment options include 5 years of aromatase inhibitors treatment or sequential therapy consisting of tamoxifen (for either 2 to 3 years or 5 years) followed by aromatase inhibitors for 2 to 3, or 5 years. Patients intolerant of aromatase inhibitors should receive tamoxifen. There are no data on the use of tamoxifen after an aromatase inhibitor in the adjuvant setting. Women with hormone receptor-negative tumors should not receive adjuvant endocrine therapy. The role of other biomarkers such as progesterone receptor and HER2 status in selecting optimal endocrine therapy remains controversial. Aromatase inhibitors are contraindicated in premenopausal women; there are limited data concerning their role in women with treatment-related amenorrhea. The side effect profiles of tamoxifen and aromatase inhibitors differ. The late consequences of aromatase inhibitor therapy, including osteoporosis, are not well characterized. CONCLUSION: The Panel believes that optimal adjuvant hormonal therapy for a postmenopausal woman with receptor-positive breast cancer includes an aromatase inhibitor as initial therapy or after treatment with tamoxifen. Women with breast cancer and their physicians must weigh the risks and benefits of all therapeutic options.

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PubMed2004

Estrogen plus progestin and colorectal cancer in postmenopausal women.

BACKGROUND: Although the Women's Health Initiative (WHI) trial of estrogen plus progestin in postmenopausal women identified more overall health risks than benefits among women in the hormone group, the use of estrogen plus progestin was associated with a significant decrease in the risk of colorectal cancer. We analyzed features of the colorectal cancers that developed and their relation to the characteristics of the participants. METHODS: In the WHI trial, 16,608 postmenopausal women who were 50 to 79 years of age and had an intact uterus were randomly assigned to a combination of conjugated equine estrogens (0.625 mg per day) plus medroxyprogesterone acetate (2.5 mg per day) or placebo. The main outcome measures were the incidence, stages, and types of colorectal cancer, as determined by blinded central adjudication. RESULTS: There were 43 invasive colorectal cancers in the hormone group and 72 in the placebo group (hazard ratio, 0.56; 95 percent confidence interval, 0.38 to 0.81; P=0.003). The invasive colorectal cancers in the hormone group were similar in histologic features and grade to those in the placebo group but with a greater number of positive lymph nodes (mean +/-SD, 3.2+/-4.1 vs. 0.8+/-1.7; P=0.002) and were more advanced (regional or metastatic disease, 76.2 percent vs. 48.5 percent; P=0.004). In exploratory analyses, women in the hormone group with antecedent vaginal bleeding had colorectal cancers with a greater number of positive nodes than women in the hormone group who did not have vaginal bleeding (3.8+/-4.3 vs. 0.7+/-1.5 nodes, P=0.006). CONCLUSIONS: Relatively short-term use of estrogen plus progestin was associated with a decreased risk of colorectal cancer. However, colorectal cancers in women who took estrogen plus progestin were diagnosed at a more advanced stage than those in women who took placebo.

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PubMed2003

Breast cancer and nonsteroidal anti-inflammatory drugs: prospective results from the Women's Health Initiative.

We analyzed data from the prospective Women's Health Initiative (WHI) Observational Study to examine the effects of regular use of aspirin, ibuprofen, and other nonsteroidal anti-inflammatory drugs (NSAIDs) on breast cancer risk. We studied a population of 80,741 postmenopausal women between 50 and 79 years of age who reported no history of breast cancer or other cancers (excluding nonmelanoma skin cancer), and we completed a personal baseline interview that elicited comprehensive health information including data on breast cancer risk factors and NSAID use. All of the cases were adjudicated by WHI physicians using pathology reports. Our analysis was based on 1392 confirmed cases of breast cancer. Relative risks (RRs) with 95% confidence intervals (CIs) were estimated with adjustment for age and other breast cancer risk factors. Regular NSAID use (two or more tablets/week) for 5-9 years produced a 21% reduction in the incidence of breast cancer (RR, 0.79; 95% CI, 0.60-1.04); regular NSAID use for 10 or more years produced a 28% reduction (RR, 0.72; CI, 0.56-0.91), and there was a statistically significant inverse linear trend of breast cancer incidence with the duration of NSAID use (P < 0.01). The estimated risk reduction for long-term use of ibuprofen (RR, 0.51; CI, 0.28-0.96) was greater than for aspirin (RR, 0.79; CI, 0.60-1.03). Subgroup analysis by breast cancer risk factors did not result in effect modification. Regular use of acetaminophen (an analgesic agent with little or no anti-inflammatory activity) or low-dose aspirin (<100 mg) was unrelated to the incidence of breast cancer. Our results indicate that the regular use of aspirin, ibuprofen, or other NSAIDs may have a significant chemopreventive effect against the development of breast cancer and underscore the need for clinical trials to confirm this effect.

Age Factors↗
PubMed2003

American Society of Clinical Oncology 2003 update on the role of bisphosphonates and bone health issues in women with breast cancer.

PURPOSE: To update the 2000 ASCO guidelines on the role of bisphosphonates in women with breast cancer and address the subject of bone health in these women. RESULTS: For patients with plain radiographic evidence of bone destruction, intravenous pamidronate 90 mg delivered over 2 hours or zoledronic acid 4 mg over 15 minutes every 3 to 4 weeks is recommended. There is insufficient evidence supporting the efficacy of one bisphosphonate over the other. Starting bisphosphonates in women who demonstrate bone destruction through imaging but who have normal plain radiographs is considered reasonable treatment. Starting bisphosphonates in women with only an abnormal bone scan but without evidence of bone destruction is not recommended. The presence or absence of bone pain should not be a factor in initiating bisphosphonates. In patients with a serum creatinine less than 3.0 mg/dL (265 mumol/L), no change in dosage, infusion time, or interval is required. Infusion times less than 2 hours with pamidronate or less than 15 minutes with zoledronic acid should be avoided. Creatinine should be monitored before each dose of either agent in accordance with US Food and Drug Administration (FDA) labeling. Oncology professionals, especially medical oncologists, need to take an expanded role in the routine and regular assessment of the osteoporosis risk in women with breast cancer. The panel recommends an algorithm for patient management to maintain bone health. CONCLUSION: Bisphosphonates provide a supportive, albeit expensive and non-life-prolonging, benefit to many patients with bone metastases. Current research is focusing on bisphosphonates as adjuvant therapy. Although new data addressing when to stop therapy, alternative doses or schedules for administration, and how to best coordinate bisphosphonates with other palliative therapies are needed, they are not currently being investigated.

Bone Density↗
PubMed2003

Influence of estrogen plus progestin on breast cancer and mammography in healthy postmenopausal women: the Women's Health Initiative Randomized Trial.

CONTEXT: The Women's Health Initiative trial of combined estrogen plus progestin was stopped early when overall health risks, including invasive breast cancer, exceeded benefits. Outstanding issues not previously addressed include characteristics of breast cancers observed among women using hormones and whether diagnosis may be influenced by hormone effects on mammography. OBJECTIVE: To determine the relationship among estrogen plus progestin use, breast cancer characteristics, and mammography recommendations. DESIGN, SETTING, AND PARTICIPANTS: Following a comprehensive breast cancer risk assessment, 16 608 postmenopausal women aged 50 to 79 years with an intact uterus were randomly assigned to receive combined conjugated equine estrogens (0.625 mg/d) plus medroxyprogesterone acetate (2.5 mg/d) or placebo from 1993 to 1998 at 40 clinical centers. Screening mammography and clinical breast examinations were performed at baseline and yearly thereafter. MAIN OUTCOME MEASURES: Breast cancer number and characteristics, and frequency of abnormal mammograms by estrogen plus progestin exposure. RESULTS: In intent-to-treat analyses, estrogen plus progestin increased total (245 vs 185 cases; hazard ratio [HR], 1.24; weighted P<.001) and invasive (199 vs 150 cases; HR, 1.24; weighted P =.003) breast cancers compared with placebo. The invasive breast cancers diagnosed in the estrogen plus progestin group were similar in histology and grade but were larger (mean [SD], 1.7 cm [1.1] vs 1.5 cm [0.9], respectively; P =.04) and were at more advanced stage (regional/metastatic 25.4% vs 16.0%, respectively; P =.04) compared with those diagnosed in the placebo group. After 1 year, the percentage of women with abnormal mammograms was substantially greater in the estrogen plus progestin group (716 [9.4%] of 7656) compared with placebo group (398 [5.4%] of 7310; P<.001), a pattern which continued for the study duration. CONCLUSIONS: Relatively short-term combined estrogen plus progestin use increases incident breast cancers, which are diagnosed at a more advanced stage compared with placebo use, and also substantially increases the percentage of women with abnormal mammograms. These results suggest estrogen plus progestin may stimulate breast cancer growth and hinder breast cancer diagnosis.

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PubMed2003

Frequency and predictive value of a mammographic recommendation for short-interval follow-up.

BACKGROUND: A recommendation for short-interval follow-up of "probably benign finding" is associated with up to 11% of screening mammograms, but its predictive value for breast cancer is unclear. We examined the predictive values (i.e., the percentage of women with a diagnosis of breast cancer 2 years after a short-interval follow-up recommendation) and likelihood ratios (derived from the pretest and post-test odds of breast cancer in the Women's Health Initiative sample) for breast cancer that are associated with a recommendation for short-interval follow-up among postmenopausal women. METHODS: We performed a longitudinal analysis of a prospective cohort of 68 126 postmenopausal women (aged 50-79 years) who were participating in clinical trials as part of the Women's Health Initiative at 40 centers across the United States. Eligible participants had screening mammograms at baseline and at least 2 years of follow-up that included a repeat mammography. Outcomes measured were breast cancer events at 1 and 2 years after baseline and the results of subsequent mammograms. All P values were two-sided. RESULTS: A total of 2927 (5%) of the 58 408 eligible women had baseline mammograms that included recommendations for short-interval follow-up. The incidence of breast cancer for women with a short-interval follow-up recommendation was 1.0% at 2 years after the baseline mammogram compared with breast cancer incidences of 0.6% and 0.5% for women whose baseline mammograms were described as "benign" and "negative," respectively. Across the 40 participating centers, the prevalence of short-interval follow-up recommendations among baseline mammograms varied from 1.2% to 9.8% (P<.001), even when the analysis was adjusted for key variables in regression models. Centers reporting higher frequencies of such recommendations did not have lower positive predictive values for breast cancer than centers reporting lower frequencies. The likelihood ratio for breast cancer after a recommendation for short-interval follow-up on a subsequent mammogram was 2.20 (95% confidence interval = 1.65 to 2.86). CONCLUSION: Having a mammographic recommendation for short-interval follow-up was associated with a low positive predictive value for breast cancer among postmenopausal women during a 2-year follow-up. This result suggests that the current criteria for this recommendation-repeat mammography within 6 months-should be reconsidered.

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PubMed2003

HT and breast cancer risk.

Two large recent studies indicate an increased risk of breast cancer with use of menopausal hormone therapy (HT), particularly combinations of estrogen and progestogen. These studies also go against previous theories of the types of breast cancer that would be associated with HT use. Emerging information regarding the influence of estrogen plus progestin on breast cancer risk adds further weight to the recommendation against use for chronic disease risk reduction and raises additional questions regarding risks of even short-term use for vasomotor symptoms associated with menopause.

Breast Neoplasms↗
PubMed2003

Research staff turnover and participant adherence in the Women's Health Initiative.

Maintaining participant adherence is a prerequisite for successful completion of randomized controlled trials requiring long-term follow-up. While patient characteristics influencing adherence are well studied, the influence of contact with clinical staff on this process has received almost no attention. To address this issue the authors evaluated the association of turnover in key clinical research staff with measures of participant adherence to protocol requirements at 40 clinical centers participating in the Women's Health Initiative (WHI), a large multicenter study. Key staff turnover in positions with potential influence on maintaining participant adherence in the Dietary Modification Clinical Trial (DM-CT) and the two Menopausal Hormone Therapy Clinical Trials (HT-CT) of the WHI was determined at each clinical center. Three prospectively established measures of participant adherence for the DM-CT and HT-CT were related to key staff turnover at each clinical center by staff category. More frequent turnover of the clinic practitioner, clinic manager, and principal investigator positions was significantly (p<0.05) associated with lower participant adherence in the HT-CT but was not associated with DM-CT participant adherence. More frequent turnover of the lead nutritionist was not associated with HT-CT participant adherence but was significantly (p<0.05) associated with one measure of decreased DM-CT participant adherence, as would be expected since the lead nutritionist did not typically see the HT-CT participants. These significant and plausible associations suggest that providing consistent contact with key staff in randomized, controlled clinical trials may facilitate long-term participant adherence. Further prospective study exploring process evaluation of the provider side of controlled trial conduct is indicated.

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PubMed2003

Differences between estimated caloric requirements and self-reported caloric intake in the women's health initiative.

PURPOSE: To compare energy intake derived from a food frequency questionnaire (FFQ) with estimated energy expenditure in postmenopausal women participating in a large clinical study. METHODS: A total of 161,856 women aged 50 to 79 years enrolled in the Women's Health Initiative (WHI) Observational Study (OS) or Clinical Trial (CT) [including the Diet Modification (DM) component] completed the WHI FFQ, from which energy intake (FFQEI) was derived. Population-adjusted total energy expenditure (PATEE) was calculated according to the Harris-Benedict equation weighted by caloric intakes derived from the National Health and Nutrition Examination Survey. Stepwise regression was used to examine the influence of independent variables (e.g., demographic, anthropometric) on FFQEI-PATEE. Race, region, and education were forced into the model; other variables were retained if they increased model explanatory ability by more than 1%. RESULTS: On average, FFQEI was approximately 25% lower than PATEE. Regression results (intercept=-799 kcal/d) indicated that body mass index (b=-23 kcal/day/kg.m(-2)); age (b=15 kcal/day/year of age); and study arm (relative to women in the OS, for DM women b=169 kcal/d, indicating better agreement with PATEE) increased model partial R(2)>.01. Results for CT women not eligible for DM were similar to those of women in the OS (b=14 kcal/d). There also were apparent differences by race (b=-152 kcal/d in Blacks) and education (b=-67 kcal/d in women with<high school). CONCLUSION: This large, carefully studied population confirms previous observations regarding underestimates in self-reported caloric intake relative to estimates of metabolic need in younger women, and those with higher weight, with less education, and in Blacks. These differences, along with effects related to intervention assignment, underline the need for additional research to enhance understanding of errors in dietary measurement.

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