BACKGROUND: Breast cancer worries are important determinants in relation to behavior favoring breast cancer screening.

OBJECTIVE: To determine the effect of theory-based training to promote breast cancer screening among women with high and low levels of breast cancer worries.

DESIGN AND SETTING: Randomized controlled trial, conducted in two family health centers.

METHODS: In total, 285 women were recruited. Women with low levels of breast cancer worries were included in the first intervention group (112 women) and the first control group (112 women), while women with high levels of breast cancer worries were included in the second intervention group (37 women) and the second control group (43 women). Theory-based training to promote breast cancer screening was given to intervention groups. The women's willingness to undergo breast cancer screening and breast cancer worry scores were evaluated at 1, 3 and 6 months.

Breast cancer is the most frequent type of cancer and the most common cause of cancer death among gynecological cancers. One in every four women with cancer in the world has breast cancer. The International Cancer Agency reported that there were around 2,088,849 new cases and 626,679 deaths due to breast cancer worldwide in 2018. The incidence of breast cancer is higher in developed countries than in developing countries, but the numbers of deaths due to breast cancer are lower in developed countries than in developing countries.

It is known that breast self-examination, clinical breast examination and mammography play an important role in making an early diagnosis of breast cancer. The uptake rate for mammography performed on a regular basis is low because this is an expensive method, considering that not all individuals have health insurance and public funding is inadequate, especially in developing countries. Hence, breast self-examination (which has no cost) and clinical breast examination (which only has low cost) remain important diagnostic methods. Moreover, during clinical breast examination, healthcare professionals have the opportunity to advise on breast cancer, risk factors, prevention methods and screening methods.

Inclusion Criteria:

• The participants included did not have any diagnosis of breast cancer, had not been performing breast self-examination regularly (every month), had not previously had a mammogram, had not previously had a clinical breast examination, were not pregnant or breastfeeding and were literate.

Exclusion Criteria:

• Missing data collection forms.