Sarah A. Edwards

Tumor Characteristics Associated With Mammographic Detection of Breast Cancer in the Ontario Breast Screening Program

BACKGROUND Few studies have compared the prognostic value of tumor characteristics by type of breast cancer diagnosed in the interval between mammographic screenings with screen-detected breast cancers. METHODS We conducted a case-case study within the cohort of women (n = 431 480) in the Ontario Breast Screening Program who were aged 50 years and older and were screened between January 1, 1994, and December 31, 2002. Interval cancers, defined as breast cancers diagnosed within 24 months after a negative screening mammogram, were designated as true interval cancers (n = 288) or missed interval cancers (n = 87) if they were not identified at the time of screening but were identified in retrospect. Screen-detected breast cancers (n = 450) were selected to match interval cancers. Tumors were evaluated for stage, grade, mitotic index, histology, and expression of hormone receptors and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by conditional logistic regression. RESULTS Both true and missed interval cancers were of higher stage and grade than matched screen-detected breast cancers. However, true interval cancers had a higher mitotic index (OR = 3.13, 95% CI = 1.81 to 5.42), a higher percentage of nonductal histology (OR = 1.94, 95% CI = 1.05 to 3.59), and were more likely to be both estrogen receptor-negative (OR = 2.09, 95% CI = 1.32 to 3.30) and progesterone receptor-negative (OR = 2.49, 95% CI = 1.68 to 3.70) compared with matched screen-detected tumors. CONCLUSIONS In this study, interval cancers were of higher stage and grade compared with screen-detected cancers. True interval cancers were more likely to have additional adverse prognostic features of estrogen and progesterone receptor negativity and nonductal morphology. The findings suggest a need for more sensitive screening modalities to detect true interval breast cancers and different approaches for early detection of fast-growing tumors.

Digital compared with screen-film mammography: performance measures in concurrent cohorts within an organized breast screening program.

PURPOSE To evaluate the performance of digital direct radiography (DR) and computed radiography (CR) compared with that of screen-film mammography (SFM) in large concurrent cohorts. MATERIALS AND METHODS This study was approved by the University of Toronto Research Ethics Board and did not require informed consent. Concurrent cohorts of women aged 50-74 years screened with DR (n = 220 520), CR (n = 64 210), or SFM (n = 403 688) between 2008 and 2009 were identified and followed for 12 months. Performance was compared between cohorts, with SFM as the referent cohort. Associations were examined by using mixed-effect logistic regression. RESULTS The cancer detection rate was similar for DR (4.9 per 1000; 95% confidence interval [CI]: 4.7, 5.2) and SFM (4.8 per 1000; 95% CI: 4.7, 5.0); however, the rate was significantly lower for CR (3.4 per 1000; 95% CI: 3.0, 3.9) (odds ratio, 0.79; 95% CI: 0.68, 0.93). Recall rates were higher for DR (7.7%; 95% CI: 7.6%, 7.8%) and lower for CR (6.6%; 95% CI: 6.5%, 6.7%) than for SFM (7.4%; 95% CI: 7.3%, 7.5%). Positive predictive value was lower for CR (5.2%; 95% CI: 4.7%, 5.8%) than for SFM (6.6%; 95% CI: 6.4%, 6.8%); however, the adjusted odds were not significant. CONCLUSION Although DR is equivalent to SFM for breast screening among women aged 50-74 years, the cancer detection rate was lower for CR. Screening programs should monitor the performance of CR separately and may consider informing women of the potentially lower cancer detection rates.

Prevalence of unassisted quit attempts in population-based studies: a systematic review of the literature.

AIMS The idea that most smokers quit without formal assistance is widely accepted, however, few studies have been referenced as evidence. The purpose of this study is to systematically review the literature to determine what proportion of adult smokers report attempting to quit unassisted in population-based studies. METHODS A four stage strategy was used to conduct a search of the literature including searching 9 electronic databases (PUBMED, MEDLINE (OVID) (1948-), EMBASE (1947-), CINAHL, ISI Web of Science with conference proceedings, PsycINFO (1806-), Scopus, Conference Papers Index, and Digital Dissertations), the gray literature, online forums and hand searches. RESULTS A total of 26 population-based prevalence studies of unassisted quitting were identified, which presented data collected from 1986 through 2010, in 9 countries. Unassisted quit attempts ranged from a high of 95.3% in a study in Christchurch, New Zealand, between 1998 and 1999, to a low of 40.6% in a national Australian study conducted between 2008 and 2009. In 24 of the 26 studies reviewed, a majority of quit attempts were unassisted. CONCLUSIONS This systematic review demonstrates that a majority of quit attempts in population-based studies to date are unassisted. However, across and within countries over time, it appears that there is a trend toward lower prevalence of making quit attempts without reported assistance or intervention.

Influence of perceived breast cancer risk on screening behaviors of female relatives from the Ontario site of the Breast Cancer Family Registry.

Few studies have examined the influence of perceived risk on breast screening behaviors among women with an increased familial breast cancer risk. This study included 1019 women aged 20–71 years from the Ontario site of the Breast Cancer Family Registry who had at least one first-degree relative diagnosed with breast and/or ovarian cancer. Information was obtained from a self-administered questionnaire completed at the time of recruitment and a follow-up telephone questionnaire. The associations between breast screening behaviors and perceived risk of developing breast cancer, measured on both a numerical and Likert-type verbal scale, were estimated using logistic regression analyses. Women who rated their risk of developing breast cancer as greater than 50% compared with less than 50% were significantly more likely to have a screening mammogram within the last 12 months (odds ratio: 1.91; 95% confidence interval: 1.15–3.16). Women were significantly more likely to have a screening mammogram (odds ratio: 1.82; 95% confidence interval: 1.17–2.81) in the past 12 months if they rated their risk as above or much above average compared with same as average or below. These findings may inform educational messages for improving risk communication of women at elevated familial breast cancer risk.

Favourable prognostic factors of subsequent screen-detected breast cancers among women aged 50-69.

Most studies reporting more favourable biological features of screen-detected breast cancers compared with symptomatic or interval cancers include initial or prevalent screens and therefore may not indicate the real benefit of screening on breast cancer mortality. We conducted case–case comparisons within a cohort of eligible women (N=771 715) who were aged 50–69 between 1 January 1995 and 31 December 2003. A randomly selected sample of breast cancers (N=1848) diagnosed among these women were compared by detection method. Tumour characteristics of interval cancers (N=362) diagnosed after 6–24 months of a negative screen or symptomatic breast cancers (N=491) were compared with subsequent screen-detected breast cancers diagnosed within 6 months of a positive screen (N=995) using polytomous logistic regression. Tumours were evaluated for clinical presentation, histology and expression of hormone receptors. Women with symptomatic detected [odds ratio (OR)=7.48, 95% confidence interval (CI)=5.38–10.38] and interval cancers (OR=2.20, 95% CI=1.56–3.10) were more often diagnosed at stage III–IV versus I than women with rescreen-detected cancers. After adjusting for tumour size, women with symptomatic cancers had tumours of higher grade (OR=1.50, 95% CI=1.05–2.15) and mitotic score (OR=1.69, 95% CI=1.15–2.49) and women with interval cancers had tumours of higher mitotic score (OR=1.52, 95% CI=1.01–2.28) compared with women diagnosed at screening. Subsequent screen-detected cancers are not only detected at an earlier stage but are also less aggressive, leading to a better prognosis. As long-term mortality reduction for breast screening may depend on subsequent screens, our study indicates that mammography screening can be effective in women aged 50–69.

Influence of Nurses on Compliance with Breast Screening Recommendations in an Organized Breast Screening Program

Background: Evidence from breast screening trials has shown that a significant reduction in breast cancer mortality from screening can be achieved by regular attendance. Few studies have evaluated the influence of nurses on compliance with breast screening recommendations. Methods: The cohort included 157,788 women ages 50 to 69 years who were screened at 1 of 9 regional cancer centers or 57 affiliated centers with nurses or 26 affiliated centers without nurses between January 1, 2002, and December 31, 2002, within the Ontario Breast Screening Program. These women were followed up prospectively for at least 30 months to compare compliance for annual and biennial screening recommendations among women who attended centers with and without nurses. The associations between type of screening center and the odds of compliance were modeled using mixed-effect logistic regression models. All P values are two-sided. Results: Women attending a regional cancer center [odds ratios (OR), 1.96; 95% confidence interval (95% CI), 1.07-3.58] or affiliated center with nurses (OR, 1.75; 95% CI, 1.38-2.22) were significantly more likely to return within 18 months of their annual screening recommendation than women attending affiliated centers without nurses. In addition, women attending regional cancer centers (OR, 2.28; 95% CI, 1.34-3.89) or affiliated centers with nurses (OR, 2.30; 95% CI, 1.86-2.83) were significantly more likely to make a timely return within the recommended biennial screening interval of between 18 and 30 months. Conclusions: Breast screening programs should consider methods of integrating educational activities as provided by the nurses to improve compliance with screening. Cancer Epidemiol Biomarkers Prev; 19(3); 697–706

Predisposing Factors Associated with Compliance to Biennial Breast Screening among Centers with and without Nurses

Background: Previous research suggests that predisposing factors such as previous screening experience, participation in preventive health behaviors, and knowledge/beliefs about breast cancer and screening influence a womans decision to make a timely return for a second screen. Methods: A stratified random sample of compliers and noncompliers to biennial screening were selected from a cohort of 51,242 women ages 50 to 65 years who had their initial screen at the Ontario Breast Screening Program. In total, 1,901 women were telephone-interviewed. The associations between predisposing factors and compliance were estimated separately for centers with and without nurses using logistic regression analyses adjusted for demographics and smoking status. Results: Women screened at nurse centers were less likely to comply if they thought women should stop having mammograms before age 70 years [odds ratio (OR), 0.39; 95% confidence interval (95% CI), 0.19-0.79], did not consider mammograms very likely to find cancer (OR, 0.73; 95% CI, 0.56-0.95), felt their likeliness of getting breast cancer was below average (OR, 0.69; 95% CI, 0.54-0.89), or believed a high-fat diet was not an important risk factor for breast cancer (OR, 0.59; 95% CI, 0.36-0.97). Women attending nurse centers were significantly more likely to comply if they sometimes had thoughts or worries about developing breast cancer (OR, 1.40; 95% CI, 1.10-1.80). Conclusions: Nurses at screening centers may reinforce a womans knowledge or beliefs about breast cancer or screening and as a result increase their compliance to biennial breast screening. (Cancer Epidemiol Biomarkers Prev 2009;18(3):739–47)

Beliefs about optimal age and screening frequency predict breast screening adherence in a prospective study of female relatives from the Ontario Site of the Breast Cancer Family Registry

BackgroundAlthough few studies have linked cognitive variables with adherence to mammography screening in women with family histories of breast and/or ovarian cancer, research studies suggest cognitive phenomena can be powerful adherence predictors.MethodsThis prospective study included 858 women aged 30 to 71 years from the Ontario site of the Breast Cancer Family Registry with at least one first-degree relative diagnosed with breast and/or ovarian cancer. Data on beliefs about breast cancer screening and use of mammography were obtained from annual telephone interviews spanning three consecutive years. Self-reported mammogram dates were confirmed with medical imaging reports. Associations between beliefs about breast cancer screening and adherence with annual mammography were estimated using polytomous logistic regression models corrected for familial correlation. Models compared adherers (N = 329) with late-screeners (N = 382) and never-screeners (N = 147).ResultsWomen who believed mammography screening should occur annually were more likely to adhere to annual screening recommendations than women who believed it should happen less often (OR: 5.02; 95% CI: 2.97-8.49 for adherers versus late-screeners; OR: 6.82; 95% CI: 3.29-14.16 for adherers versus never-screeners). Women who believed mammography screening should start at or before age 50 (rather than after) (OR: 9.72; 95% CI: 3.26-29.02) were significantly more likely to adhere when compared with never-screeners.ConclusionsStudy results suggest that women with a family history of breast cancer should be strongly communicated recommendations about initial age of screening and screening intervals as related beliefs significantly predict adequate adherence.

Association Between Socioeconomic Status and Access to Care and Quitting Smoking With and Without Assistance

Introduction Socio-economic disparities in smoking rates persist, in Ontario, despite public health care and universal tobacco control policies. Mechanisms for continuing disparities are not fully understood. Unequal access or utilization of assistance for cessation may contribute. The objective of this research was to use longitudinal data on smokers to examine the associations between socioeconomic status (SES) and access to care measures and assisted and unassisted quit attempts. Methods Data were taken from 3578 smokers with at least one follow-up interview participating in the Ontario Tobacco Survey (OTS). Multinomial regression models with imputed missing values were run for each measure of SES and access to care to assess the association with quitting behavior and use of assistance, unadjusted and while adjusting for smoking history and demographic covariates. Results Adjusted analyses found smokers living in areas with the lowest ethnic concentration were more likely to make an assisted quit attempt compared to unassisted quitting (RR = 1.64; 95% CI = 1.08-2.50) or making no quit attempt (RR = 1.65; 95% CI = 1.15-2.37). Smokers who reported visiting a doctor in the previous 6 months were more likely to quit with assistance versus unassisted compared to those not visiting a doctor, whether they were advised (RR = 1.89, 95% CI = 1.43-2.48) or not advised to quit (OR = 1.32, 95% CI = 1.01-1.74). Similar results were seen when comparing assisted quit attempts with no quit attempts. Conclusions Adjusted analyses showed that quitting with assistance was unrelated to measures of SES except ethnic concentration. Physician intervention with patients who smoke is important for increasing assisted quit attempts. Implications For most measures of SES there were no significant associations with either assisted or unassisted quitting adjusting for demographic and smoking history. Smokers who live in areas with the lowest ethnic concentration were most likely to use assistance as were smokers who visited their doctor and were advised to quit smoking. Interventions to increase the delivery of effective quitting methods in smokers living in areas with high ethnic concentrations and to increase physician compliance with asking and advising patients to quit may increase assisted quit attempts.