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    Time to begin adjuvant chemotherapy and survival in breast cancer patients: a retrospective observational study using latent class analysis. Downing Amy,Twelves Christopher,Forman David,Lawrence Gill,Gilthorpe Mark S The breast journal The analysis of time to treatment data and the evaluation of subsequent effects on health outcomes can be complex due to the nature of the data and the relationships amongst the variables. This study proposes an alternative method of analyzing such data using latent class analysis (LCA). The association between time to begin adjuvant chemotherapy after breast cancer surgery and survival was investigated using both "traditional" regression analysis and LCA. Women with breast cancer undergoing surgery and subsequent adjuvant chemotherapy in two English regions between January 01, 1998 and December 31, 2004 were identified from a linked cancer registry-Hospital Episode Statistics dataset (n = 10,366). Patient, tumor, and treatment information were extracted. A Cox proportional hazards model was used to analyze 5-year survival using regression analysis and LCA. Using "traditional" regression analysis, women beginning chemotherapy >10 weeks after surgery had worse survival in region 1 (HR = 1.49, 95% CI 1.13-1.95 compared to <3 weeks) but not region 2. LCA split the women into three groups representing short, medium, and long waits. The median time to begin chemotherapy in the "long" wait group was 70 (region 1) and 57 (region 2) days. In this group, increased time to begin chemotherapy was associated with worse survival (region 1 HR = 1.15, 95% CI 1.11-1.18; region 2 HR = 1.08, 95% CI 1.03-1.13 per week increase). LCA identified a group of 13-15% of women for whom a longer time to begin chemotherapy had an adverse effect on survival. This methodology provides an excellent framework in which to examine complex associations between the delivery of patient care and patient outcomes. 10.1111/tbj.12209
    Health-related quality of life in lung cancer survivors: Latent class and latent transition analysis. Kenzik Kelly M,Martin Michelle Y,Fouad Mona N,Pisu Maria Cancer BACKGROUND:Health-related quality of life (HRQOL) heterogeneity among cancer survivors may mask subgroups (classes) with different limitations and long-term outcomes. The authors determined the HRQOL classes that exist among lung cancer survivors, examined transitions among those classes over time, and compared survival outcomes of patients according to the classes present in the initial phase of care. METHODS:Lung cancer survivors in the Cancer Care Outcomes Research and Surveillance Consortium completed EuroQol 5-domain quality-of-life questionnaires 4.8 months (initial phase) and >1 year (survivorship phase) after diagnosis (n = 1396). Latent class analysis and latent transition analysis were used to determine HRQOL classes and transitions across time. Correlates of class membership were tested using multinomial logistic regression. Kaplan-Meier and Cox regression analyses were used to compare survival across class membership. RESULTS:Latent class analysis identified 4 classes at diagnosis and follow-up: 1) poor HRQOL, 2) pain-dominant impairment, 3) mobility/usual activities impairment, and 4) good HRQOL. Probabilities of remaining in the same class were .87, .85, .82, and .73 for classes 4, 1, 3, and 2, respectively. Younger age, lower income, lower education, comorbidities, and a history of depression/emotional problems were associated with a greater likelihood of being in classes 1, 2, or 3 at follow-up. Patients in classes 1 and 3 had significantly lower median survival estimates than patients in class 4 (4.8 years, 3.8 years, and 5.5 years, respectively; P < .001). CONCLUSIONS:Examining the heterogeneity of HRQOL in lung cancer populations allows the identification of classes with different limitations and long-term outcomes and, thus, guides tailored and patient-centered provision of supportive care. 10.1002/cncr.29232
    Latent Class Analysis Reveals Distinct Subgroups of Patients Based on Symptom Occurrence and Demographic and Clinical Characteristics. Miaskowski Christine,Dunn Laura,Ritchie Christine,Paul Steven M,Cooper Bruce,Aouizerat Bradley E,Alexander Kimberly,Skerman Helen,Yates Patsy Journal of pain and symptom management CONTEXT:Cancer patients experience a broad range of physical and psychological symptoms as a result of their disease and its treatment. On average, these patients report 10 unrelieved and co-occurring symptoms. OBJECTIVES:The aims were to determine if subgroups of oncology outpatients receiving active treatment (n = 582) could be identified based on their distinct experience with 13 commonly occurring symptoms; to determine whether these subgroups differed on select demographic and clinical characteristics; and to determine if these subgroups differed on quality of life (QOL) outcomes. METHODS:Demographic, clinical, and symptom data from one Australian and two U.S. studies were combined. Latent class analysis was used to identify patient subgroups with distinct symptom experiences based on self-report data on symptom occurrence using the Memorial Symptom Assessment Scale. RESULTS:Four distinct latent classes were identified (i.e., all low [28.0%], moderate physical and lower psych [26.3%], moderate physical and higher psych [25.4%], and all high [20.3%]). Age, gender, education, cancer diagnosis, and presence of metastatic disease differentiated among the latent classes. Patients in the all high class had the worst QOL scores. CONCLUSION:Findings from this study confirm the large amount of interindividual variability in the symptom experience of oncology patients. The identification of demographic and clinical characteristics that place patients at risk for a higher symptom burden can be used to guide more aggressive and individualized symptom management interventions. 10.1016/j.jpainsymman.2014.12.011
    Associations between Personal Care Product Use Patterns and Breast Cancer Risk among White and Black Women in the Sister Study. Taylor Kyla W,Troester Melissa A,Herring Amy H,Engel Lawrence S,Nichols Hazel B,Sandler Dale P,Baird Donna D Environmental health perspectives BACKGROUND:Many personal care products include chemicals that might act as endocrine disruptors and thus increase the risk of breast cancer. OBJECTIVE:We examined the association between usage patterns of beauty, hair, and skin-related personal care products and breast cancer incidence in the Sister Study, a national prospective cohort study (enrollment 2003-2009). METHODS:Non-Hispanic black (4,452) and white women (n=42,453) were examined separately using latent class analysis (LCA) to identify groups of individuals with similar patterns of self-reported product use in three categories (beauty, skin, hair). Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between product use and breast cancer incidence. RESULTS:A total of 2,326 women developed breast cancer during follow-up (average follow-up=5.4y). Among black women, none of the latent class hazard ratios was elevated, but there were <100 cases in any category, limiting power. Among white women, those classified as "moderate" and "frequent" users of beauty products had increased risk of breast cancer relative to "infrequent" users [HR=1.13 (95% CI: 1.00, 1.27) and HR=1.15 (95% CI: 1.02, 1.30), respectively]. Frequent users of skincare products also had increased risk of breast cancer relative to infrequent users [HR=1.13 (95% CI: 1.00, 1.29)]. None of the hair product classes was associated with increased breast cancer risk. The associations with beauty and skin products were stronger in postmenopausal women than in premenopausal women, but not significantly so. CONCLUSIONS:This work generates novel hypotheses about personal care product use and breast cancer risk. Whether these results are due to specific chemicals or to other correlated behaviors needs to be evaluated. https://doi.org/10.1289/EHP1480. 10.1289/EHP1480
    Heterogeneous demographic and cultural profiles of Chinese American patients nonadherent to colorectal cancer screening: a latent class analysis. Strong Carol,Ji Cheng Shuang,Liang Wenchi,Ma Grace,Brown Roger,Wang Judy Huei-yu Cancer nursing BACKGROUND:Colorectal cancer (CRC) is one of the leading causes of cancer death in Chinese Americans, but their CRC screening rates remain low. OBJECTIVE:We examined subgroups of Chinese American patients nonadherent to CRC screening guidelines to better inform clinical practices to effectively promote screening. METHODS:Using latent class analysis of data from 327 participants recruited from 18 primary care clinics, we classified nonadherent patients based on sociodemographics, screening barriers, and attitudinal and clinical factors for CRC screening. RESULTS:The best-fitting latent class analysis model described 3 distinctive classes: Western healthcare class (36%), Eastern healthcare class (18%), and mixed healthcare class (46%). Western healthcare class patients were highly educated, with average US residency of 20 years, a high level of English proficiency, the least Eastern cultural views of care, and the greatest exposure to physician recommendations, but reported having no time for screenings. Eastern healthcare class patients were highly educated seniors and recent immigrants with the least CRC knowledge and the most Eastern cultural views. Mixed healthcare class patients had low level of education, resided in the United States for 20 years, and half had sought services of their physicians for at least 3 years, but their knowledge and cultural views were similar to those of Eastern healthcare class patients. CONCLUSIONS:Nonadherent Chinese American patients are heterogeneous. It is essential to have future intervention programs tailored to address specific screening beliefs and barriers for subtypes of nonadherent patients. IMPLICATIONS FOR PRACTICE:Training primary care physicians to recognize patients' different demographic characteristics and healthcare beliefs may facilitate physicians' communication with patients to overcome their barriers and improve screening behaviors. 10.1097/NCC.0b013e3182888b5b
    Body weight trajectories and risk of oesophageal and gastric cardia adenocarcinomas: a pooled analysis of NIH-AARP and PLCO Studies. Petrick Jessica L,Kelly Scott P,Liao Linda M,Freedman Neal D,Graubard Barry I,Cook Michael B British journal of cancer BACKGROUND:Elevated body mass index (BMI, kg m) has been consistently associated with oesophageal adenocarcinoma (EA) and gastric cardia adenocarcinoma (GCA) incidence. However, effects of adiposity over the life course in relation to EA/GCA have not been thoroughly explored. METHODS:We pooled two prospective cohort studies: NIH-AARP Diet and Health Study and Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, with data on 409 796 individuals (633 EA, 415 GCA). At baseline, participants reported their height and weight at ages 20 and 50 years, and current. Body mass index trajectories were determined using latent class analysis. Hazard ratios (HRs) and 95% confidence intervals (CI) were estimated using proportional hazards regression. RESULTS:Compared with individuals with a BMI<25 kg m at all time points, exceeding a BMI of 25 kg m at age 20 was associated with increased risks of EA (HR=1.76, 95% CI: 1.35-2.29) and GCA (HR=1.62, 95% CI: 1.16-2.25). Similarly, a BMI trajectory of overweight (⩾25-<30 kg m) at age 20 progressing to obesity (⩾30 kg m) by age 50 was associated with increased risks of EA (HR=2.90, 95% CI: 1.67-5.04) and GCA (HR=4.07, 95% CI: 2.32-7.15), compared with individuals with a normal weight (⩾18.5-<25 kg m) trajectory. Weight gain of ⩾20 kg between age 20 and baseline was also associated with a two times increased risk of EA (HR=1.97, 95% CI: 1.43-2.73) and more modestly with GCA (HR=1.40, 95% CI: 0.96-2.05). CONCLUSIONS:Being overweight in early adulthood and weight gain later in life were each associated with increased risks of EA and GCA. This underscores the potential of weight control programs for reducing EA and GCA risk. 10.1038/bjc.2017.29