Introduction
In the USA more than 234000 cases of breast cancer would be diagnosed annually. Breast cancer constitutes 25% of the new cases of cancer among women. In 2012, 1.7 million new cases of breast cancer were diagnosed all around the world (1). In Asia, due to the changes in fertility pattern and lifestyle, the incidence of breast cancer has been constantly increasing over the time. For example in Korea, age-specific incidence of breast cancer among women of 45 to 49 years old has been tripled to 140 cases in every 100000 women (2, 3). During the past decade, the incidence of breast cancer has been increased by 30% in China and India. In Iran also breast cancer is the most common cancer among women; Iranian women would be affected by breast cancer at least a decade sooner than their fellow women living in developed countries (4). According to the latest official report by the Iranian Cancer Registry of Ministry of Health and Medical Education, the age-standardized incidence of breast cancer was reported to be 28.25. The age-standardized incidence of breast cancer in Yazd, which is located in the center of Iran, is reported to be 38.52 (5). Movahedi et al. (2012) reported that the five-year survival rate of breast cancer in Iran is 71% while this rate is increased to 85% in developed countries (6). One of the main reasons for increased rate of mortality by breast cancer among Iranian women is few referrals for monitoring and delayed visits to physicians (7). Therefore early diagnosis of breast cancer using mammography could probably decrease the rate of mortality and improve the survival rate (8). In Iran 70% of women would refer to physicians during the advanced stages of the disease when it is too late for treatment (9). Results of a qualitative study showed that psychological factors like embarrassment, fear of the diagnosis of cancer, preoccupation with underlying diseases, the need for having a companion, internalizing the experiences of others and misunderstanding about mammography and maladaptive coping patterns like avoidance and denial, religious beliefs and belief in fate were some of the obstacles for performing mammography (10). Elabaid et al. (2014) reported that although the national monitoring program for breast cancer was conducted in the UAE for free based on the international framework for monitoring, but the rate of referrals was only 10% and about 65% of the patients would refer during advanced stages of the disease. In this study 44.1% of women who had never performed mammography stated that they had no information about the methods of monitoring (11). Cultural and social barriers would vary in different countries and is specific to every region (12). For monitoring breast cancer in developing countries, it is recommended to design educational interventions based on theories (13). Trans theoretical Model (TTM) would be a helpful framework for monitoring for breast cancer screening using mammography. The TTM has a stage construct and would suggest that changes would occur over time and people would pass stages like pre-contemplation, contemplation, preparation, action and maintenance to change their behaviors; other constructs of this model include self-efficacy, the balance of decision–making and also the processes of change (14). Self-efficacy means having sufficient self-esteem to overcome obstacles. The balance of decision-making is like the process of weighing the strengths and weaknesses to adapt a new behavior against an old behavior. Using the processes of change could be helpful in understanding the occurrence of change in people (15). The findings of the study for evaluating the stages of change for adapting monitoring behaviors for breast cancer among Korean women showed that most of them (50.8%) were in the stage of action/maintenance, and only 2.6% were in the stage of relapse. (16). Results of the study showed that most of Iranian women (40%) were in the stage of pre-contemplation, and only 5.8% were in the stage of maintenance (17). After a literature review, it was revealed that few studies were conducted on Iranian women based on the framework of the TTM and considering the prevalence of breast cancer among women in Yazd. This study aimed to determine the predicting factors of mammography adherence among Iranian women based on TTM. Results of the present study could be helpful in developing educational programs for improving preventive behaviors of breast cancer, encouraging women to be more sensitive about their breast health, in-time diagnosis of probable cancer and desirably controlling it.
Methods
This cross-sectional study was conducted on 300 married women in Yazd in 2018. Cluster sampling was done from health centers of Yazd. Each of the urban health centers (4 centers) were considered as a cluster and random sampling was conducted in each cluster. Tabachnick and Fidell (2013) proposed using formula of “50+8m” where “m” is the number of predictors (18). This study considered 300 subjects with coefficient of determination equals to 2 to apply regression model that are sufficiently accurate to represent the parameters in the targeted population. The qualified women were allocated randomly to each cluster (n=75).
After conducting a pilot study for evaluating the reliability of the questionnaire, from the medical records of the families under coverage of the health center some were randomly selected and women who lived at the same region were contacted. If a visiting date was set for women, they were called and asked to come to the center. The inclusion criteria were being female, being 40 years old or more, willingness to participate in the study, being a native residence of Yazd, speaking Farsi, being able to read and write, not having breast cancer and not having psychiatric disorders. The exclusion criteria were unwillingness to participate in the study, moving to another city or region for living.
Considering lack of a reliable and valid Farsi questionnaire based on TTM for evaluating women’s in mammography behaviors, by reviewing articles, a native questionnaire was developed to evaluate the constructs of TTM.
Data gathering tool was a questionnaire which included demographic information, history of breast diseases, history of taking mammography: reasons for having a mammography, reasons for not having a mammography (no physician’s advice, not calling to remind for the mammography, unawareness, harmfulness of mammography for health), showing the results of mammography to the specialist, age at the first mammography, and the method of preference for reminding the next mammography visits (phone call, massage, written invitation), decision-making steps for performing mammography questionnaire, self-efficacy scale; in this part the participants would face questions that would challenge their ability to perform a mammography. In this part women would answer questions with a 4-point Likert scale from “not sure” to “completely sure”, the balance of decision-making scale. This scale includes 6 questions about the pros and 11 questions about the cons. These questions were answered with a 4-point scale from “totally agree” to “totally disagree”. The change process questionnaire; this part included 20 questions about the processes of change in behaviors related to mammography. In this study both groups of experimental and cognitive processes were regarded. 4-points Likert scale from “totally agree” to “totally disagree” was used for answering this part.
The validity of the questionnaires was approved through face and content validity. Qualitative and quantitative methods were used for approving content validity. For determining the internal consistency of the questionnaire, it was given to 15 to 30 women referred to the selected health centers and the Cronbach’s α was calculated; values more than 0.7 were considered acceptable. In this study, Cornbrash's alpha of this questionnaire was 0.94. Data were analyzed in SPSS statistics for windows, version 16.0 (SPSS Inc., Chicago, III., USA) using chi-square test, Spearman correlation coefficient, one-way analysis of variance, and regression analysis with a significant level of α = 0.05. Regarding the questions of process of change, self-efficacy and balance of decision-making, the range of scores for each participant was divided by the number of questions; so each participant’s mean score was calculated. The range of score for the self-efficacy construct was 8 to 32. For ranking the level of self-efficacy, based on their gained scores, participants were divided into three groups of poor (8-15), moderate (16-23) and good (24-32). To determine the balance of decision-making, the score of perceived barriers was subtracted for the score of perceived benefits.
Ethical issues including getting permission from the research council of the university for conducting the study, providing sufficient information to every participant about the study, assuring the participants about confidentiality of their information and voluntarily participation in the study, were regarded. All the participants signed a written informed consent.
Results
The mean age of women was 47.25±6.97 years old (ranged from 40 to 70). The majority of them were housewives (84.3%), and had health insurance (93%), only 15.7% of them were employed. Regarding their educational level, 53% of them had an under-diploma degree, and 18.7% had college degrees. Mean score of studied women's age at the first mammography was 41.92