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Dive into the research topics where Theresa H.M. Keegan is active.

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Featured researches published by Theresa H.M. Keegan.


American Journal of Public Health | 2006

Outdoor Falls Among Middle-Aged and Older Adults: A Neglected Public Health Problem

Wenjun Li; Theresa H.M. Keegan; Barbara Sternfeld; Stephen Sidney; Charles P. Quesenberry; Jennifer L. Kelsey

OBJECTIVES Although risk factors for indoor falls among older individuals have been well studied, little is known about the etiology of outdoor falls. We examined risk factors for outdoor falls among middle-aged and older adults. METHODS We analyzed data on the most recent fall during the past year among participants aged 45 years and older in the control group (N=2193) of a case-control study of fractures. The study was conducted at 5 Northern California Kaiser Permanente Medical Centers between 1996 and 2001. RESULTS Falls occurred outdoors more often than indoors among most age groups. Study participants who reported more leisure-time physical activity had a higher risk for outdoor falls, and participants who were in poorer health had a greater risk for indoor falls. Most outdoor falls (73%) were precipitated by environmental factors, such as uneven surfaces and tripping or slipping on objects, and usually occurred on sidewalks, curbs, and streets. Walking (47.3%) was the most common fall-related activity. CONCLUSIONS Outdoor falls among adults aged 45 years and older were frequently attributable to modifiable environmental factors. With the widespread promotion of active lifestyles among older people, improvements in their outdoor environment are urgently needed.


Cancer | 2012

Positive and negative psychosocial impact of being diagnosed with cancer as an adolescent or young adult

Keith M. Bellizzi; Ashley Wilder Smith; Steven D. Schmidt; Theresa H.M. Keegan; Brad Zebrack; Charles F. Lynch; Dennis Deapen; Margarett Shnorhavorian; Bradley J. Tompkins; Michael S. Simon

The objective of this study was to explore the psychosocial impact of cancer on newly diagnosed adolescent and young adult (AYA) cancer patients.


JAMA | 2014

Use of and mortality after bilateral mastectomy compared with other surgical treatments for breast cancer in California, 1998-2011.

Allison W. Kurian; Daphne Y. Lichtensztajn; Theresa H.M. Keegan; David O. Nelson; Christina A. Clarke; Scarlett Lin Gomez

IMPORTANCE Bilateral mastectomy is increasingly used to treat unilateral breast cancer. Because it may have medical and psychosocial complications, a better understanding of its use and outcomes is essential to optimizing cancer care. OBJECTIVE To compare use of and mortality after bilateral mastectomy, breast-conserving therapy with radiation, and unilateral mastectomy. DESIGN, SETTING, AND PARTICIPANTS Observational cohort study within the population-based California Cancer Registry; participants were women diagnosed with stages 0-III unilateral breast cancer in California from 1998 through 2011, with median follow-up of 89.1 months. MAIN OUTCOMES AND MEASURES Factors associated with surgery use (from polytomous logistic regression); overall and breast cancer-specific mortality (from propensity score weighting and Cox proportional hazards analysis). RESULTS Among 189,734 patients, the rate of bilateral mastectomy increased from 2.0% (95% CI, 1.7%-2.2%) in 1998 to 12.3% (95% CI, 11.8%-12.9%) in 2011, an annual increase of 14.3% (95% CI, 13.1%-15.5%); among women younger than 40 years, the rate increased from 3.6% (95% CI, 2.3%-5.0%) in 1998 to 33% (95% CI, 29.8%-36.5%) in 2011. Bilateral mastectomy was more often used by non-Hispanic white women, those with private insurance, and those who received care at a National Cancer Institute (NCI)-designated cancer center (8.6% [95% CI, 8.1%-9.2%] among NCI cancer center patients vs 6.0% [95% CI, 5.9%-6.1%] among non-NCI cancer center patients; odds ratio [OR], 1.13 [95% CI, 1.04-1.22]); in contrast, unilateral mastectomy was more often used by racial/ethnic minorities (Filipina, 52.8% [95% CI, 51.6%-54.0%]; OR, 2.00 [95% CI, 1.90-2.11] and Hispanic, 45.6% [95% CI, 45.0%-46.2%]; OR, 1.16 [95% CI, 1.13-1.20] vs non-Hispanic white, 35.2% [95% CI, 34.9%-35.5%]) and those with public/Medicaid insurance (48.4% [95% CI, 47.8%-48.9%]; OR, 1.08 [95% CI, 1.05-1.11] vs private insurance, 36.6% [95% CI, 36.3%-36.8%]). Compared with breast-conserving surgery with radiation (10-year mortality, 16.8% [95% CI, 16.6%-17.1%]), unilateral mastectomy was associated with higher all-cause mortality (hazard ratio [HR], 1.35 [95% CI, 1.32-1.39]; 10-year mortality, 20.1% [95% CI, 19.9%-20.4%]). There was no significant mortality difference compared with bilateral mastectomy (HR, 1.02 [95% CI, 0.94-1.11]; 10-year mortality, 18.8% [95% CI, 18.6%-19.0%]). Propensity analysis showed similar results. CONCLUSIONS AND RELEVANCE Use of bilateral mastectomy increased significantly throughout California from 1998 through 2011 and was not associated with lower mortality than that achieved with breast-conserving surgery plus radiation. Unilateral mastectomy was associated with higher mortality than were the other 2 surgical options.


Journal of Clinical Oncology | 2013

Health-Related Quality of Life of Adolescent and Young Adult Patients With Cancer in the United States: The Adolescent and Young Adult Health Outcomes and Patient Experience Study

Ashley Wilder Smith; Keith M. Bellizzi; Theresa H.M. Keegan; Brad Zebrack; Vivien W. Chen; Anne Victoria Neale; Ann S. Hamilton; Margarett Shnorhavorian; Charles F. Lynch

PURPOSE Adolescents and young adults (AYAs) diagnosed with cancer face numerous physical, psychosocial, and practical challenges. This article describes the health-related quality of life (HRQOL) and associated demographic and health-related characteristics of this developmentally diverse population. PATIENTS AND METHODS Data are from the Adolescent and Young Adult Health Outcomes and Patient Experience (AYA HOPE) study, a population-based cohort of 523 AYA patients with cancer, ages 15 to 39 years at diagnosis from 2007 to 2009. Comparisons are made by age group and with general and healthy populations. Multiple linear regression models evaluated effects of demographic, disease, health care, and symptom variables on multiple domains of HRQOL using the Pediatric Quality of Life Inventory (PedsQL) and the Short-Form Health Survey 12 (SF-12). RESULTS Overall, respondents reported significantly worse HRQOL across both physical and mental health scales than did general and healthy populations. The greatest deficits were in limitations to physical and emotional roles, physical and social functioning, and fatigue. Teenaged patients (ages 15 to 17 years) reported worse physical and work/school functioning than patients 18 to 25 years old. Regression models showed that HRQOL was worse for those in treatment, with current/recent symptoms, or lacking health insurance at any time since diagnosis. In addition, sarcoma patients, Hispanic patients, and those with high school or lower education reported worse physical health. Unmarried patients reported worse mental health. CONCLUSION Results suggest that AYAs with cancer have major decrements in several physical and mental HRQOL domains. Vulnerable subgroups included Hispanic patients, those with less education, and those without health insurance. AYAs also experienced higher levels of fatigue that were influenced by current symptoms and treatment. Future research should explore ways to address poor functioning in this understudied group.


Journal of Clinical Oncology | 2005

Epstein-Barr Virus As a Marker of Survival After Hodgkin's Lymphoma: A Population-Based Study

Theresa H.M. Keegan; Sally L. Glaser; Christina A. Clarke; Margaret L. Gulley; Fiona E. Craig; Joseph A. DiGiuseppe; Ronald F. Dorfman; Risa B. Mann; Richard F. Ambinder

PURPOSE Epstein-Barr virus (EBV) in Hodgkins lymphoma (HL) cells has been considered as a prognostic marker for this heterogeneous disease, but studies have yielded mixed findings, likely because of selected patient series and failure to acknowledge an effect of age on outcome. This study assessed survival after HL in a population-based cohort large enough to examine the joint effects of EBV with other factors including age, sex, and histologic subtype. PATIENTS AND METHODS Included were 922 patients with classical HL diagnosed between mid-1988 and 1997 in the Greater San Francisco Bay Area, with archived biopsy specimens assayed for EBV with immunohistochemistry and in situ hybridization. Vital status was followed through December 30, 2003 (median follow-up time, 97 months). Overall and disease-specific survival were analyzed with the Kaplan-Meier method and Cox proportional hazards regression models. RESULTS In children less than 15 years old, EBV presence was suggestively associated (P = .07) with favorable survival. In adults aged 15 to 44 years, EBV did not affect HL outcome, although a protective effect was suggested. In older adults (45 to 96 years), EBV presence nearly doubled the risk of overall and HL-specific mortality but only for patients with nodular sclerosis (NS) histologic subtype (hazard ratio for death = 2.5; 95% CI, 1.5 to 4.3). CONCLUSION In HL, EBV tumor cell presence is associated with better survival in young patients and poorer survival in older patients with NS, independent of other factors. Variation in outcome by age and histology could indicate biologically distinct disease entities. Evidence that EBV is a meaningful prognostic marker may have therapeutic relevance.


Journal of the National Cancer Institute | 2012

Age-Specific Incidence of Breast Cancer Subtypes: Understanding the Black–White Crossover

Christina A. Clarke; Theresa H.M. Keegan; Juan Yang; David J. Press; Allison W. Kurian; Anish H. Patel; James V. Lacey

BACKGROUND Breast cancer incidence is higher among black women than white women before age 40 years, but higher among white women than black women after age 40 years (black-white crossover). We used newly available population-based data to examine whether the age-specific incidences of breast cancer subtypes vary by race and ethnicity. METHODS We classified 91908 invasive breast cancers diagnosed in California between January 1, 2006, and December 31, 2009, by subtype based on tumor expression of estrogen receptor (ER) and progesterone receptor (PR)-together referred to as hormone receptor (HR)-and human epidermal growth factor receptor 2 (HER2). Breast cancer subtypes were classified as ER or PR positive and HER2 negative (HR(+)/HER2(-)), ER or PR positive and HER2 positive (HR(+)/HER2(+)), ER and PR negative and HER2 positive (HR(-)/HER2(+)), and ER, PR, and HER2 negative (triple-negative). We calculated and compared age-specific incidence rates, incidence rate ratios, and 95% confidence intervals by subtype and race (black, white, Hispanic, and Asian). All P values are two-sided. RESULTS We did not observe an age-related black-white crossover in incidence for any molecular subtype of breast cancer. Compared with white women, black women had statistically significantly higher rates of triple-negative breast cancer at all ages but statistically significantly lower rates of HR(+)/HER2(-) breast cancers after age 35 years (all P < .05). The age-specific incidence of HR(+)/HER2(+) and HR(-)/HER2(+) subtypes did not vary markedly between white and black women. CONCLUSIONS The black-white crossover in breast cancer incidence occurs only when all breast cancer subtypes are combined and relates largely to higher rates of triple-negative breast cancers and lower rates of HR(+)/HER2(-) breast cancers in black vs white women.


American Journal of Public Health | 2010

Hidden breast cancer disparities in asian women: Disaggregating incidence rates by ethnicity and migrant status

Scarlett Lin Gomez; Thu Quach; Pamela L. Horn-Ross; Jane T. Pham; Myles Cockburn; Ellen T. Chang; Theresa H.M. Keegan; Sally L. Glaser; Christina A. Clarke

OBJECTIVES We estimated trends in breast cancer incidence rates for specific Asian populations in California to determine if disparities exist by immigrant status and age. METHODS To calculate rates by ethnicity and immigrant status, we obtained data for 1998 through 2004 cancer diagnoses from the California Cancer Registry and imputed immigrant status from Social Security Numbers for the 26% of cases with missing birthplace information. Population estimates were obtained from the 1990 and 2000 US Censuses. RESULTS Breast cancer rates were higher among US- than among foreign-born Chinese (incidence rate ratio [IRR] = 1.84; 95% confidence interval [CI] = 1.72, 1.96) and Filipina women (IRR = 1.32; 95% CI = 1.20, 1.44), but similar between US- and foreign-born Japanese women. US-born Chinese and Filipina women who were younger than 55 years had higher rates than did White women of the same age. Rates increased over time in most groups, as high as 4% per year among foreign-born Korean and US-born Filipina women. From 2000-2004, the rate among US-born Filipina women exceeded that of White women. CONCLUSIONS These findings challenge the notion that breast cancer rates are uniformly low across Asians and therefore suggest a need for increased awareness, targeted cancer control, and research to better understand underlying factors.


Breast Cancer Research | 2012

Occurrence of breast cancer subtypes in adolescent and young adult women

Theresa H.M. Keegan; Mindy C. DeRouen; David J. Press; Allison W. Kurian; Christina A. Clarke

IntroductionBreast cancers are increasingly recognized as heterogeneous based on expression of receptors for estrogen (ER), progesterone (PR), and human epidermal growth factor receptor 2 (HER2). Triple-negative tumors (ER-/PR-/HER2-) have been reported to be more common among younger women, but occurrence of the spectrum of breast cancer subtypes in adolescent and young adult (AYA) women aged between 15 and 39 years is otherwise poorly understood.MethodsData regarding all 5,605 AYA breast cancers diagnosed in California during the period 2005 to 2009, including ER and PR status (referred to jointly as hormone receptor (HR) status) and HER2 status, was obtained from the population-based California Cancer Registry. Incidence rates were calculated by subtype (triple-negative; HR+/HER2-; HR+/HER2+; HR-/HER2+), and logistic regression was used to evaluate differences in subtype characteristics by age group.ResultsAYAs had higher proportions of HR+/HER2+, triple-negative and HR-/HER2+ breast cancer subtypes and higher proportions of patients of non-White race/ethnicity than did older women. AYAs also were more likely to be diagnosed with stage III/IV disease and high-grade tumors than were older women. Rates of HR+/HER2- and triple-negative subtypes in AYAs varied substantially by race/ethnicity.ConclusionsThe distribution of breast cancer subtypes among AYAs varies from that observed in older women, and varies further by race/ethnicity. Observed subtype distributions may explain the poorer breast cancer survival previously observed among AYAs.


American Journal of Public Health | 2010

Disparities in Breast Cancer Survival Among Asian Women by Ethnicity and Immigrant Status: A Population-Based Study

Scarlett Lin Gomez; Christina A. Clarke; Sarah J. Shema; Ellen T. Chang; Theresa H.M. Keegan; Sally L. Glaser

OBJECTIVES We investigated heterogeneity in ethnic composition and immigrant status among US Asians as an explanation for disparities in breast cancer survival. METHODS We enhanced data from the California Cancer Registry and the Surveillance, Epidemiology, and End Results program through linkage and imputation to examine the effect of immigrant status, neighborhood socioeconomic status, and ethnic enclave on mortality among Chinese, Japanese, Filipino, Korean, South Asian, and Vietnamese women diagnosed with breast cancer from 1988 to 2005 and followed through 2007. RESULTS US-born women had similar mortality rates in all Asian ethnic groups except the Vietnamese, who had lower mortality risk (hazard ratio [HR] = 0.3; 95% confidence interval [CI] = 0.1, 0.9). Except for Japanese women, all foreign-born women had higher mortality than did US-born Japanese, the reference group. HRs ranged from 1.4 (95% CI = 1.2, 1.7) among Koreans to 1.8 (95% CI = 1.5, 2.2) among South Asians and Vietnamese. Little of this variation was explained by differences in disease characteristics. CONCLUSIONS Survival after breast cancer is poorer among foreign- than US-born Asians. Research on underlying factors is needed, along with increased awareness and targeted cancer control.


Journal of Clinical Oncology | 2011

Clinical Trial Participation and Time to Treatment Among Adolescents and Young Adults With Cancer: Does Age at Diagnosis or Insurance Make a Difference?

Helen M. Parsons; Linda C. Harlan; Nita L. Seibel; Jennifer L. Stevens; Theresa H.M. Keegan

PURPOSE Because adolescent and young adult (AYA) patients with cancer have experienced variable improvement in survival over the past two decades, enhancing the quality and timeliness of cancer care in this population has emerged as a priority area. To identify current trends in AYA care, we examined patterns of clinical trial participation, time to treatment, and provider characteristics in a population-based sample of AYA patients with cancer. METHODS Using the National Cancer Institute Patterns of Care Study, we used multivariate logistic regression to evaluate demographic and provider characteristics associated with clinical trial enrollment and time to treatment among 1,358 AYA patients with cancer (age 15 to 39 years) identified through the Surveillance, Epidemiology, and End Results Program. RESULTS In our study, 14% of patients age 15 to 39 years had enrolled onto a clinical trial; participation varied by type of cancer, with the highest participation in those diagnosed with acute lymphoblastic leukemia (37%) and sarcoma (32%). Multivariate analyses demonstrated that uninsured, older patients and those treated by nonpediatric oncologists were less likely to enroll onto clinical trials. Median time from pathologic confirmation to first treatment was 3 days, but this varied by race/ethnicity and cancer site. In multivariate analyses, advanced cancer stage and outpatient treatment alone were associated with longer time from pathologic confirmation to treatment. CONCLUSION Our study identified factors associated with low clinical trial participation in AYA patients with cancer. These findings support the continued need to improve access to clinical trials and innovative treatments for this population, which may ultimately translate into improved survival.

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Ashley Wilder Smith

National Institutes of Health

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Ann Brunson

University of California

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Helen M. Parsons

University of Texas Health Science Center at San Antonio

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Ted Wun

University of California

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Qian Li

University of California

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Linda C. Harlan

National Institutes of Health

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Ann S. Hamilton

University of Southern California

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