CMAJ/JAMC Evidence
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Effect of breast self-examination techniques on the risk of death from breast cancer

Bart J. Harvey, MD, PhD; Anthony B. Miller, MB, ChB; Cornelia J. Baines, MD, MSc; Paul N. Corey, PhD

CMAJ 1997;157:1205-12

[ résumé ]

From the Department of Public Health Sciences, Faculty of Medicine, University of Toronto, Toronto, Ont.

This article has been peer reviewed.

Reprint requests to: Dr. Bart J. Harvey, Department of Public Health Sciences, 4th floor, McMurrich Building, University of Toronto, Toronto ON M5S 1A8; fax 416 978-8299

© 1997 Canadian Medical Association (text and abstract/résumé)

See also:
Contents
Abstract

Objective: To measure the effect of breast self-examination (BSE) technique and frequency on the risk of death from breast cancer.

Design: Case­control study nested within the Canadian National Breast Screening Study (NBSS).

Setting: The Canadian NBSS, a multicentre randomized controlled trial of screening for breast cancer in Canadian women.

Subjects: The case subjects were 163 women who had died from breast cancer and 57 women with distant metastases. Ten control subjects matched by 5-year age group, screening centre, year of enrolment and random allocation group were randomly selected for each case subject.

Exposure measures: Self-reported BSE frequency before enrolment in the NBSS, annual self-reports of BSE frequency during the program and annual objective assessments of BSE technique.

Outcome measures: Odds ratios (ORs) associated with BSE practice were estimated by conditional multiple logistic regression modelling, which permitted control of covariates.

Results: Relative to women who, when assessed 2 years before diagnosis, examined their breasts visually, used their finger pads for palpation and examined with their 3 middle fingers, the OR for death from breast cancer or distant metastatic disease for women who omitted 1, 2 or 3 of these components was 2.20 (95% confidence interval [CI] 1.30 to 3.71, p = 0.003). The OR for women who omitted 1 of the 3 components was 1.82 (95% CI 1.00 to 3.29, p = 0.05), for those who omitted 2 of the 3 components, 2.84 (95% CI 1.44 to 5.59, p = 0.003), and for those who omitted all 3 components, 2.95 (95% CI 1.19 to 7.30, p = 0.02). The results remained unchanged after adjustment for potential confounders.

Conclusion: The results, obtained with the use of prospectively collected data, suggest that the performance of specific BSE components may reduce the risk of death from breast cancer.

Résumé

Objectif : Mesurer l'effet de la technique d'autoexamen des seins et sa fréquence d'utilisation sur le risque de décès des suites d'un cancer du sein.

Conception : Étude cas­témoin incluse dans l'Étude nationale sur le dépistage du cancer du sein au Canada.

Contexte : L'Étude nationale sur le dépistage du cancer du sein au Canada, étude contrôlée, randomisée et multicentrique sur le dépistage du cancer du sein chez les femmes du Canada.

Sujets : Les sujets étaient 163 femmes mortes du cancer du sein et 57 femmes atteintes de métastases à distance. Pour chaque cas sujet, on a choisi 10 sujets témoins jumelés par groupe d'âge étalé sur 5 ans, centre de dépistage, année d'inscription et groupe de randomisation.

Mesures du risque : Fréquence autodéclarée de l'autoexamen des seins avant la participation à l'enquête nationale, rapports annuels des intéressées sur la fréquence de l'autoexamen des seins au cours du programme et évaluation annuelle objective de la technique d'autoexamen des seins.

Mesures des résultats : On a estimé des coefficients de probabilité associés à l'autoexamen des seins par modélisation de régression logistique multiple conditionnelle, ce qui a permis de contrôler les covariables.

Résultats : Dans le cas des femmes qui, évaluées 2 ans avant le diagnostic, procédaient à un autoexamen des seins, utilisaient leur coussinet tactile pour procéder à une palpation et utilisaient leurs 3 doigts du milieu pour l'examen, le coefficient de probabilité (CP) de décès des suites d'un cancer du sein ou de métastases à distance chez les femmes qui ont omis 1, 2 ou 3 de ces éléments s'est établi à 2,20 (intervalle de confiance [IC] à 95 %, 1,30 à 3,71 p = 0,003). Le CP s'est établi à 1,82 (IC à 95 %, 1,00 à 3,29, p = 0,05) chez les femmes qui ont omis 1 des 3 éléments, à 2,84 (IC à 95 %, 1,44 à 5,59, p = 0,003) chez celles qui en ont omis 2, et à 2,95 (IC à 95 %, 1,19 à 7,30, p = 0,02) chez celles qui les ont omises toutes les 3. Les résultats sont demeurés inchangés après rajustement pour facteurs de confusion éventuels.

Conclusion : Les résultats, tirés de données recueillies de façon prospective, indiquent que l'utilisation de certaines techniques en particulier d'autoexamen des seins peut réduire le risque de décès des suites d'un cancer du sein.

[ Contents ]

Introduction

Breast cancer is an important cause of illness and a leading cause of death and potential years of life lost.1­3 Early detection followed by timely treatment is important.

Periodic screening mammography with or without clinical breast examination reduces rates of death from breast cancer for women aged 50 to 69 years.4,5 Another method, breast self-examination (BSE), is self-administered and inexpensive. However, it is not without risks.6­11 Both false-positive and false-negative results of BSE carry costs and risks. Furthermore, if BSE leads to earlier detection without affecting rates of illness and death due to breast cancer, it results only in an extension of the time a woman is aware of the diagnosis. Thus, it is important to determine the benefits of BSE and to compare them with the associated risks and costs.12,13

Although BSE has long been advocated,14,15 the first evidence of its effectiveness came in 1978 from 2 descriptive studies.16,17 Despite a call for more rigorous studies of BSE,13 many similar studies followed. These examined the correlation between the practice of BSE and the stage of disease at, or survival following, diagnosis. The conclusions from these correlational studies were questioned by 2 review groups6,18 and other investigators7,8,11 because of the potential effects of recall, loss to follow-up, nonresponse, self-selection, lead time and length biases.

Two randomized controlled trials are currently under way, one in Russia19 and the other in China.20 The Russian trial has not yet provided results. However, Thomas and colleagues20 recently reported preliminary results from the first 5 years of follow-up. That analysis showed neither lower death rates nor a shift toward the diagnosis of less advanced disease among the subjects practising BSE. It is uncertain whether these trial results will be in any way generalizable to a North American population.

A nonrandomized community-controlled trial in the United Kingdom has provided equivocal 10-year results.21 The relative risk for death from breast cancer was 1.13 (95% confidence interval [CI] 0.95 to 1.35) for one BSE centre but only 0.78 (95% CI 0.61 to 1.00) for the other BSE centre. The investigators have been unable to account for the conflicting results.22

In a cohort study Gastrin and associates23 examined the experience of women enrolled in the comprehensive BSE-promoting Mama Program in Finland. The rate of death from breast cancer for the 28 785 program enrollees who completed and returned a calendar recording their BSE practice was found to be significantly lower than national rates, with an observed-to-expected ratio of 0.71 (95% CI 0.57 to 0.87). This occurred despite the fact that the enrollees' incidence of breast cancer was 20% higher than expected.

Case­control studies are also used to evaluate screening.24 Newcomb and collaborators25 carried out a population-based case­control study to examine the relation between BSE and the occurrence of advanced breast cancer. Although they found no beneficial effect associated with reported BSE frequency, the small proportion of women who reported more thorough BSE had a significantly decreased occurrence of advanced disease compared with less proficient practitioners. Muscat and Huncharek26 found no significant difference in the frequency of BSE between a group of women with advanced breast cancer and a comparison group (odds ratio [OR] 1.27, 95% CI 0.77 to 2.07). In contrast, a study by Locker and coworkers,27 nested within the Nottingham Centre of the UK Trial of Early Detection of Breast Cancer,21 found attendance for BSE education to be protective against death from breast cancer (OR 0.70, 95% CI 0.50 to 0.97).

In this article we describe a case­control study of BSE, nested within the Canadian National Breast Screening Study (NBSS), designed to measure the effect of BSE techniques on the risk of death due to breast cancer.

[ Contents ]

Methods

Canadian National Breast Screening Study

The Canadian NBSS is a multicentre randomized controlled trial of screening mammography28­32 that recruited 89 835 volunteers between 1980 and 1985. Eligible women were aged 40 to 59 years, had no history of breast cancer, were not pregnant, had not undergone mammography in the 12 months before study entry and signed informed consent. Self-administered questionnaires yielded information on menstrual, reproductive, hormonal and family history and on frequency of BSE. All of the participants received BSE instruction.

At their initial visits, 50 430 women aged 40 to 49 years were randomly allocated either to a group that received 4 or 5 annual screenings consisting of 2-view mammography and clinical breast examination or to a group that received only clinical breast examination on enrolment but not rescreening. A total of 39 405 women aged 50 to 59 years were allocated either to a group that received 4 or 5 annual screenings consisting of mammography and clinical breast examination or to a group that received 4 or 5 annual screenings of clinical breast examination only.

Each year each participant, including those not eligible for rescreening, also received a self-administered questionnaire inquiring about BSE practice in the preceding year. BSE evaluation and instruction were conducted at each rescreening visit.

Subjects

Eligible subjects for the case­control study of BSE were all NBSS participants except those in whom breast cancer was diagnosed before their second year in the NBSS, who were excluded to eliminate the influence of pre-existing cancer. The initial assessment of BSE practice did not occur until each woman's first rescreening visit.

Case subjects were women who had died from breast cancer or in whom distant metastatic disease was reported during follow-up. Women with metastatic disease, a valid surrogate end-point for death, were included to enhance the study's power. Study cases were identified by the ongoing annual NBSS follow-up procedures31 for all women with a diagnosis of breast cancer and by record linkages with Statistics Canada's National Mortality Database and the cancer registries of the 6 provinces where the NBSS operated.

For each case subject, 10 control subjects were randomly selected from the remaining eligible women (all women who were alive at the time the case subject died or was determined to have distant metastatic disease). Therefore, the control subjects could include women with diagnosed breast cancer. However, if they subsequently manifested distant metastases or died from breast cancer they were eligible to become case subjects. To ensure that case and control subjects had comparable opportunities for breast cancer screening, the control subjects were matched by 5-year age group, screening centre, enrolment year and random allocation group.

Exposure measures

During the NBSS, the following data on BSE were collected prospectively: self-reported BSE frequency before enrolment in the NBSS, annual self-reports of BSE frequency during the program and annual assessments of BSE technique by the NBSS screen-examiners. The last 2 measures were examined in relation to each of up to 3 years preceding the diagnosis of breast cancer.

Because the objective, structured assessment of BSE technique was instituted after the NBSS started, approximately 15% of the participants did not have their BSE technique assessed at their year-2 screening visit. Women aged 40 to 49 years who were randomly allocated to the control group were not eligible for rescreening, so their BSE technique was never assessed.

Screen-examiners conducted assessments of the subjects' BSE technique before performing the clinical examination of the breasts.32 To avoid undermining a participant's willingness to attend further screening visits, the screen-examiners were flexible in conducting the BSE assessments. Although most women agreed to demonstrate their technique, others wished only to describe it, some provided information during the clinical examination of their breasts, and a small number declined the evaluation.

Eight components were evaluated individually to assess BSE technique and frequency (the practices considered proficient are noted in parentheses): visual examination (included), fingers used for examination (middle three), surfaces used for examination (finger pads), search pattern used (not random), palpation technique used (small circles), coverage of the examination (all or most of the breast), axillae examination (included) and BSE frequency (12 or more times per year).

Because women were ineligible for screening after a diagnosis of breast cancer, BSE technique was evaluated only up until the time of diagnosis. For each case­control set, assessment of BSE and other screening procedures was limited to the same interval -- the time before the first breast-cancer diagnosis within the set.

We examined the effect of covariates such as age, family history of breast cancer, age at menarche, past history of breast problems, parity, age at first live birth, age at menopause, marital status, smoking history, education and occupation.

Data analysis

We used conditional multiple logistic regression modelling to estimate the ORs, 95% CIs and probability values associated with BSE, and to control for covariates (PHREG procedure, SAS/STAT software, ver. 6, SAS Institute Inc., Cary, NC, 1991).

[ Contents ]

Results

The case subjects were 163 women (74.1%) who died from breast cancer and 57 women (25.9%) with distant metastases. Of the 2200 randomly selected matched control subjects, 18 were found to have breast cancer, 3 of whom were also included as cases (owing to subsequent development of distant metastases in 2 of these subjects and death from breast cancer in 1).

The demographic characteristics of the case and control subjects were similar in many respects (Table 1). However, a larger proportion of case subjects than of control subjects held management or professional occupations and were current smokers. Breast cancer risk factors, such as lower age at menarche, higher age at menopause and family history of breast cancer, were more common among the case subjects than among the control subjects (Table 2). The apparently decreased risk associated with hysterectomy did not persist after we adjusted for age at menopause (adjusted OR 0.89, 95% CI 0.57 to 1.39, p = 0.60).

Table 3 shows that similar proportions of case and
control subjects reported having undergone mammography (27% v. 29%) (p = 0.57) and having practised BSE (44% v. 50%) (p = 0.10) before entry into the NBSS.

Self-reported information about BSE practice was available for more than 85% of the eligible case and control subjects. Failure to return follow-up questionnaires (8%) and returning questionnaires without specifying BSE practice (6%) were responsible for the missing responses. Information from the screen-examiner assessment was available for more than 80% of the eligible case and control subjects. This information was not available for the remainder of the subjects, for the following reasons: the subject did not attend the rescreening visit (11%), the rescreening visit occurred before the structured assessment of BSE technique was implemented (6%), or the assessment was not completed during the rescreening visit (1%).

Self-reported BSE frequency, which was stable over the 3 periods examined, was not associated with case status (Table 4).

When all 8 BSE components assessed were examined in a single regression model, the ORs associated with failure to perform 3 of the components -- a visual examination, palpation with the 3 middle fingers and examination with the finger pads -- were found to vary over the 3 periods examined. The ORs for each of these components were greatest for the assessment 2 years before diagnosis: relative to women who included all 3 components, the OR for death from breast cancer or distant metastatic disease for women who omitted 1 of the 3 components was 1.82 (95% CI 1.00 to 3.29, p = 0.05), for those who omitted 2 of the 3 components, 2.84 (95% CI 1.44 to 5.59, p = 0.003), and for those who omitted all 3 components, 2.95 (95% CI 1.19 to 7.30, p = 0.02) (Table 4). Because factors such as family history of breast cancer, age at menarche, age at menopause, education and occupation did not affect the results, unadjusted ORs are presented.

[ Contents ]

Discussion

These results, like those from other studies, support a benefit from BSE. However, the potential effects of lead time, length and recall biases have been eliminated by the study's design. In addition, ours is the only study to categorize BSE technique according to prospective, objective assessments. However, the post hoc assessment of the 8 components over 3 periods may have resulted in an overestimate of the observed associations. In addition, because we did not use an experimental design, our results may be confounded, owing to differing risks inherent in the 2 groups rather than a true screening effect.

Nesting this study within the NBSS reduced the possibility of selection bias. Each participant was a volunteer who gave informed consent before entering the NBSS. Compliance was similar: 82.8% (144/174) of the case subjects and 80.9% (1408/1740) of the control subjects attended all scheduled NBSS screening visits. The control subjects were matched with the case subjects by age, random allocation group, screening centre and enrolment year. Potential confounders did not affect the results.

The effect of BSE practice was evident only when assessed 2 years before the diagnosis of breast cancer. This appears consistent with the observations of Weiss, McKnight and Stevens,33 who pointed out that if screening is to be effective it must be done during the time when the tumour is both detectable and curable. Our results suggest that BSE 1 year before diagnosis is too late to be effective.

Our overall results are consistent with those of the population-based case­control study carried out in Seattle by Newcomb and collaborators.25 Their study suggested that women who are not proficient at BSE are at significantly greater risk for advanced breast cancer than their more proficient counterparts.

Although our study and that of Newcomb and collaborators25 arrived at similar results, the 2 studies examined different BSE practices. Newcomb and collaborators assessed BSE practice using a 10-point scale, based on the sum of positions and techniques mentioned in each woman's BSE description: lying down; sitting upright; with arm over or behind head; standing in front of mirror; using a circular motion or all around or outward and inward motion; using the flat of 2 or 3 fingertips; checking nipples; checking underarms; looking for dimpling, swelling and discoloration; and any other reasonable examination technique (Polly A. Newcomb, PhD, University of Wisconsin Cancer Center, Madison, Wis.: personal communication, 1994). The data presented by Newcomb and collaborators allow only 1 of the common factors to be compared: examination of the axillae. Although those investigators found a significant difference in this component of BSE between the case and control subjects, a similar effect was not evident from the NBSS data.

Both studies found no association between BSE frequency and the risk of death from breast cancer. Also, neither found a protective effect associated with prior mammography; rather, both found an increased risk associated with multiple previous mammographic examinations. In seeking explanations for this finding, the Seattle investigators found that women who reported frequent previous mammographic examinations were far more likely than women without such a history to have had previous "benign breast disease" or palpable lumps that were followed with mammography (Polly A. Newcomb: personal communication, 1994). Similarly, we found that women who had multiple previous mammographic examinations were more likely to have reported prior "breast problems" and a family history of breast cancer.

The Seattle investigation,25 like the study carried out by Senie and colleagues,34 showed a significant protective effect associated with the number of previous clinical breast examinations. Information about prior clinical breast examinations was not collected from women when they entered the NBSS. However, because existing cases of breast cancer were excluded, mammography and clinical breast examinations done before the NBSS should be of less relevance to our study.

Our findings are also compatible with the results of the correlational study by Hislop, Coldman and Skippen.35 Those investigators found that women who did not palpate their breasts were twice as likely as women who included this practice to have lymph node involvement at diagnosis and that women who included a thorough visual inspection of their breasts were twice as likely as those who omitted this practice to have tumours smaller than 2 cm in diameter at diagnosis (p = 0.05 for both findings).

In conclusion, evidence from our study and from the population-based case­control study by Newcomb and collaborators25 suggests that proficient BSE practice may reduce the risk of death from breast cancer.

We thank the nearly 90 000 Canadian women who made the National Breast Screening Study possible through their generous participation.

The Canadian National Breast Screening Study was supported by the Canadian Cancer Society, the federal Department of National Health and Welfare (now Health Canada), the National Cancer Institute of Canada, the Alberta Heritage Fund for Cancer Research, the Manitoba Health Services Commission, the Medical Research Council of Canada, the Ministère de la Santé et des Services sociaux du Québec, the Nova Scotia Department of Health and the Ontario Ministry of Health. Dr. Harvey was supported by a Health Research Personnel Development Program doctoral fellowship (no. 01560) from the Ontario Ministry of Health. Dr. Miller was supported in part by a National Health Scientist Award from Health Canada. Dr. Baines was supported in part by the National Cancer Institute of Canada.

References
  1. Wingo PA, Tong T, Boulden S. Cancer statistics, 1995. CA Cancer J Clin 1995;45:8-30.
  2. National Cancer Institute of Canada. Canadian cancer statistics 1995. Toronto: The Institute; 1995.
  3. Bryant HE, Brasher PMA. Risks and probabilities of breast cancer: short-term versus lifetime probabilities. CMAJ 1994;150:211-6.
  4. Morrison AS. Review of evidence on the early detection and treatment of breast cancer. Cancer 1989;64(12 suppl):2651-6.
  5. Fletcher SW, Black W, Harris R, Rimer BK, Shapiro S. Report of the International Workshop on Screening for Breast Cancer. J Natl Cancer Inst 1993;85:1644-56.
  6. O'Malley MS, Fletcher SW. Screening for breast cancer with breast self-examination: a critical review. JAMA 1987;257:2197-203.
  7. Prorok PC. Epidemiologic approach for cancer screening: problems in design and analysis of trials. Am J Pediatr Hematol Oncol 1992;14:117-28.
  8. Hurley SF, Kaldor JM. The benefits and risks of mammographic screening for breast cancer. Epidemiol Rev 1992;14:101-30.
  9. Frank JW, Mai V. Breast self-examination in young women: More harm than good? Lancet 1985;2:654-7.
  10. Cole P, Austin H. Breast self-examination: an adjunct to early cancer detection. Am J Public Health 1981;71:572-4.
  11. Cole P, Morrison AS. Basic issues in population screening for cancer. J Natl Cancer Inst 1980;64:1263-72.
  12. Sox HC, Woolf SH. Evidence-based practice guidelines from the US Preventive Services Task Force [editorial]. JAMA 1993;269:2678.
  13. Moore FD. Breast self-examination. N Engl J Med 1978;299:304-5.
  14. Adair FE. Clinical manifestations of early cancer of the breast -- with a discussion on the subject of biopsy. N Engl J Med 1933;208:1250-5.
  15. Haagensen CD. Self-examination of the breasts. JAMA 1952;149:356-60.
  16. Foster RS Jr, Lang SP, Costanza MC, Worden JK, Haines CR, Yates JW. Breast self-examination practices and breast-cancer stage. N Engl J Med 1978;299:265-70.
  17. Greenwald P, Nasca PC, Lawrence CE, Horton J, McGarrah RP, Gabriele T, et al. Estimated effect of breast self-examination and routine physician examinations on breast cancer mortality. N Engl J Med 1978;299:271-3.
  18. Hill D, White V, Jolley D, Mapperson K. Self examination of the breast: Is it beneficial? Meta-analysis of studies investigating breast self examination and extent of disease in patients with breast cancer. BMJ 1988;297:271-5.
  19. Semiglazov VF, Sagaidak VN, Moiseyenko VM, Mikhailov EA. Study of the role of breast self-examination in the reduction of mortality from breast cancer: the Russian Federation/World Health Organization Study. Eur J Cancer 1993;29A:2039-46.
  20. Thomas DB, Gao DL, Self SG, Allison CJ, Tao Y, Mahloch J, et al. Randomized trial of breast self-examination in Shanghai: methodology and preliminary results. J Natl Cancer Inst 1997;89:355-65.
  21. UK Trial of Early Detection of Breast Cancer Group. Breast cancer mortality after 10 years in the UK Trial of Early Detection of Breast Cancer. Breast 1993;2:13-20.
  22. Ellman R, Moss SM, Coleman D, Chamberlain J. Breast self-examination programmes in the Trial of Early Detection of Breast Cancer: ten year findings. Br J Cancer 1993;68:208-12.
  23. Gastrin G, Miller AB, To T, Aronson KJ, Wall C, Hakama M, et al. Incidence and mortality from breast cancer in the Mama Program for breast screening in Finland, 1973­1986. Cancer 1994;73:2168-74.
  24. Weiss NS. Application of the case­control method in the evaluation of screening. Epidemiol Rev 1994;16:102-8.
  25. Newcomb PA, Weiss NS, Storer BE, Scholes D, Young BE, Voigt LF. Breast self-examination in relation to the occurrence of advanced breast cancer. J Natl Cancer Inst 1991;83:260-5.
  26. Muscat JE, Huncharek MS. Breast self-examination and extent of disease: a population-based study. Cancer Detect Prev 1991;15:155-9.
  27. Locker AP, Caseldine J, Mitchell AK, Blamey RW, Roebuck EJ, Elston CW. Results from a seven-year programme of breast self-examination in 89,010 women. Br J Cancer 1989;60:401-5.
  28. Miller AB, Howe GR, Wall C. The national study of breast cancer screening: protocol for a Canadian randomized trial of screening for breast cancer in women. Clin Invest Med 1981;4:227-58.
  29. Miller AB, Baines CJ, To T, Wall C. Canadian National Breast Screening Study: 1. Breast cancer detection and death rates among women aged 40 to 49 years [published correction appears in CMAJ 1993;148:718]. CMAJ 1992;147:1459-76.
  30. Miller AB, Baines CJ, To T, Wall C. Canadian National Breast Screening Study: 2. Breast cancer detection and death rates among women aged 50 to 59 years [published correction appears in CMAJ 1993;148:718]. CMAJ 1992;147:1477-88.
  31. Baines CJ. The Canadian National Breast Screening Study: a perspective on criticisms. Ann Intern Med 1994;120:326-34.
  32. Baines CJ, To T. Changes in breast self-examination behavior achieved by 89,835 participants in the Canadian National Breast Screening Study. Cancer 1990;66:570-6.
  33. Weiss NS, McKnight B, Stevens NG. Approaches to the analysis of case­control studies of the efficacy of screening for cancer. Am J Epidemiol 1992;135:817-23.
  34. Senie RT, Rosen PP, Lesser ML, Kinne DW. Breast self-examination and medical examination related to breast cancer stage. Am J Public Health 1981;71:583-90.
  35. Hislop TG, Coldman AJ, Skippen DH. Breast self-examination: importance of technique in early diagnosis. CMAJ 1984;131:1349-52.

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