Written informed consent was obtained from all participants and they were informed that participation was voluntary, and all personal information was confidential. The ethical permission was received from manager desk of high schools (no 56/7, date 10 Sep 2017). Also, an educational pamphlet was designed and provided freely for all participants, also a face-to-face discussion and conversation has been performed by the main researcher (KFD).

This study was performed as a cross-sectional analytical research study, on high-school students from different region of Tabriz City, East Azerbaijan, North West of Iran, from 22 September 2017 to 19 June 2018 (academic year in Iran). Based on previous similar study [19], and using STATA software, the least value of the Odds Ratio (OR) 2, and by considering a 95% confidence level, 90% Power, with α error=0.05, and 20% for dropout, the sample size resulted 500 cases. The study subjects’ of 500 students, selected as simple randomisation from 4 different high-schools who agreed to answer the questionnaires and participated in study. The schools were selected randomly from four main regions, one school from each formal educational area of Tabriz City. In Iran, students started the high-school from 14 years old and duration was 6 years.

Inclusion criteria: Participants were aged between 14 to 19 years, high-school students and living in Tabriz.

Exclusion criteria: Participants unwilling to participate in the study.

Questionnaire was designed and implement according to researchers’ aims and scopes using references [13,19,20]. This questionnaire was a Persian self-administered, anonymous, easy to answer tool and needed about 10-15 minutes to fill. The scientific validity of the instrument was determined by the validity of the content. The reliability of the instrument was also calculated by Cronbach’s alpha coefficient. The average estimated Cronbach’s alpha coefficient was 0.79, with Spearman’s Brown Correlation of 0.68 in this reference study [19].

First the socio-demographic information was obtained, which has been validated before [13] and contains questions about parent(s) current marital status, parent(s) education, residency, and family income. For family income, it was somehow difficult to identify income amounts per month in Iran, so it was categorised as family satisfaction level as low, moderate, good, and very good. The response options were designed as Likert scales and each variable scored from worst to best status and the total scores indicated the SDS. Based on reference [13], the cut-points used for SDS were considered as poor for 1-5, moderate for 6-10, good for 11-15, and perfect for >15 scores.

Then 65 questions were provided about the knowledge (n=20), attitude (n=20) and protective behaviour (n=25) regarding cancer, in general for all cancers [13,20]. They were assessed with three answers from disagree, agree, completely agree (means that I agree with every aspect of this question) and coded as Likert scales (score ranges are provided below). Knowledge dimension was evaluated about cancer causes, risk factors, chemical and hazards exposures, dietary and life-style factors; attitude about self-perceived risk of cancer, perception of general beliefs about cancer cause, cancer treatment, cancer prevention; and Protective behaviours, beliefs about early detection and screening modalities for most common cancers in world, Iran and East Azerbaijan; modification and improvement of dietary and life style habits; avoid risky habits attributed to cancer were assessed. First, the scores were calculated for each sub-category:

Knowledge: 0-20 poor, 21-40 moderate, 41-60 good;

Attitude: 0-20 poor, 21-40 moderate, 41-60 good;

Protective behaviour: 0-25 poor, 26-50 moderate, 50-75 good.

In order to better assess the level of knowledge, attitude, and protective behaviours, the total scores obtained in these areas (for knowledge, attitude, and protective behaviour) were summarised and then categorised into five groups from worst to best status as: 0-40 (very poor), 41-80 (poor), 81-120 (moderate), 121-160 (good) and 161-195 (very good).

Student volunteers, after receiving information about the aims and methods of study and after getting consent forms, involved in study. Filled questionnaire were gathered and primary information were summarised in excel file. The results were registered and recorded, and each criteria were scored according to defined measurement and scales. After calculating the scores of knowledge, attitude, and protective behaviour, all scores were summarised and converted to range.

Demographic data and average score results were analysed using STATA MP 14.2 (Stata Corp LP, College Station, Texas 77845 USA). Basic descriptive data were presented as number and percentages for nominal, and mean±standard deviation for numeric variable. The normality of numeric data was tested by Skewness and kurtosis tests. Multinomial Logistic regression analysis was performed to assess any relationship between socio-demographic factors and knowledge and attitude, and behaviour scores. Adjusted Odd Ratios (ORs) along with 95% Confidence Intervals (CIs) were presented. Two tailed p-value was considered significant at ≤0.05 level. The dependent variable was the total score of knowledge, attitude and protective behaviours’ scores, as was multinomial as: Very Poor, Poor, Moderate, Good, and Very Good.

From 500 enrolled students, 471 students accepted to participate in this survey, 251 (53.3%) were male and 220 (46.7%) were female. They were between 14-19-year-old with mean age of 16.79 (±SD 1.22) years. A total of 232 (49.3%) students had positive family history at least one from any cancer. The mean SDS was 11.68 (±SD 2.02) with range of 6 to 18 scores, which was considered almost good according to the defined category. Most of the students was in good SDS (332, 70.5%), and 130 (27.6%) in moderate SDS, and just 9 students (1.9%) were in perfect SDS [Table/Fig-1].

For knowledge, attitude and protective behaviours the scores were calculated separately and then the total scores were gained. The total mean score for three dimensions, in 471 students was 136.05 (±SD 3.24) which was considered as good according to the defined categories. From these 73 students (15.5%) had moderate and 398 students (84.5%) had good total scores. None of the 471 students had very poor, poor and very good total scores [Table/Fig-2].

Multinomial regression analysis was performed, and the dependent variable was score of knowledge, attitude and protective behaviours’ and their total scores, as was multinomial. Main effects were used like model, included intercept, and model fitting information. 95% CIs and likelihood ratio tests were assessed, and covariate patterns by factors were defined.

The results showed that SDS had some effects on each skills, as students with higher SDS had higher knowledge, attitude, and protective behaviours. Students with good SDS had about 2 times higher knowledge scores (OR=2.25; 95% CI: 1.59-8.58), about 3 times higher attitude scores (OR=2.92; 95% CI=1.74-11.45), and about 4 times higher protective behaviour scores (OR=3.76; 95% CI: 1.98-7.13, p=0.001).

Total scores of knowledge, attitude and protective behaviour was significantly higher in better SDS of students, as students with moderate SDS had 3.85 times higher total scores (OR=3.85; 95% CI=2.03-7.29, p=0.001) and students with good SDS had about 2 times higher total scores (OR=1.94; 95% CI=1.42-4.91, p=0.001) and these differences were statistically significant. Also, male students had slightly higher total scores compared to female students (OR=1.15; 95% CI=0.69-1.89, p=0.59) but this was not statistically significant. Increasing age of the students their total scores were significantly increased, but the higher total score was obtained in 16-17th age group, which 16-17 old-ages had about 2 times higher total scores than 14-15ths (OR=1.97; 95% CI=1.03-3.76, p=0.04). Positive family history at least one, from any cancer didn’t have significant association with knowledge scores at all [Table/Fig-3]. The choice of variables was taken after the discussion with statistician in this [Table/Fig-3].

The aim of this cross-sectional analytic study was to evaluate the main aspects of knowledge, attitude and protective behaviour regarding different aspects of cancer including risk factors, cancer cause, cancer treatment, cancer prevention, and cancer early detection and screening. The study also evaluated the SDS of 471 male and female high-school students, from 4 randomly selected high-schools of Tabriz, East Azerbaijan and assess any relationship between SDS and knowledge, attitude and preventive behaviour’s total scores. The higher SDS was significantly associated with higher knowledge levels of students, as students with moderate SDS had about 4 times and students with good SDS about 2 times higher levels of knowledge, attitude and protective behaviour. The results showed better levels of knowledge, attitude and protective behaviour levels at all high-school students of Tabriz as about 84.5% had higher scores which defined as good level. Also, as students get older their knowledge, attitude and protective behaviour levels increased significantly.

Although there were few studies about knowledge and attitude about all aspects of cancer in general populations, there were limited studies on high-school students, at least in Iran [4-8,19]. So, because of the importance and significance of these age groups as the main future makers of communities, this study was performed. Some free educational pamphlets were provided including main risk factors of most common cancers, early detection and screening modalities, and healthy diet and life style rules. Also, the last information about most common cancers statistics in East Azerbaijan was provided using the results of East Azerbaijan Population Based Cancer Registry data as a book for all of the students.

There was disparity and conflicting results about knowledge and attitude and SDS in high-school students. There were very low knowledge levels in male and female high-school students [21,22], even in developed world in high-school students [23,24]. Lack of knowledge, attitude and behaviours was obvious in high-school students of Saudi Arabia, while the mean knowledge index was 22.9% [22,25]. Many students reported that they may have heard about any aspects of cancer, but low percentage of them had any attitude and interest to find scientific and descriptive information about the same [22]. However, the results showed a good knowledge, attitude and protective behaviour levels, comparing with previous reports from Iran and East Azerbaijan [5,26-29]. Having at least one positive family history has a large impact on young adolescents to have attitude about any cancer and risk factors [22,23]. In this study, any association between positive family history and knowledge levels in the high-school students did not found.

Providing and enhancing knowledge and attitude and deliver and conduction of evidence based information and beliefs about all aspects of cancer in adolescent life period is so important, as it provides accurate teaching skills and shaping health behaviours and beliefs into adulthood in early stages of their life [21,30]. These knowledge and skills can help and empower young adolescent to play main roles in their healthy life style and risk factor controls and responsibility for their own and family, friends and relatives health behaviours [21]. Conducting educational interventions, training and raising the knowledge levels of students have had significantly efficient impact in high-school students’ knowledge, attitude and protective behaviour regarding all aspects of cancer [30]. It has been well established that educational programs had significantly positive effect on promote awareness, attitudes and preventive behaviour of cancer, in high-school students [4,19]. So developing and establishing evidence based education and giving the right information in young adolescent group is strongly recommended. Public health policy makers and cancer epidemiologists are responsible to design and implement continuous educational training programs for young adults, even starting from primary schools and enhancing to high-schools and continue at university levels [31].

SDS had a strong impact on knowledge and attitude levels of high-school students. Parent(s) higher educational levels help young adolescent to be more interested and curious about updated information about cancer, while most of the students received their knowledge from their parent (s). Educated families are the most important source of information in theses age groups [30]. Also, according to previous experiences most adolescents gain their knowledge and information from different media sources [23,24]. Access and availability of these sources is mostly dependent to SDS of families and their provided facilities for their children. Meanwhile higher educated parent (s), provide more and accurate information about risky behaviours regarding cancers, and then better protective beliefs and behaviour like smoking, dietary habits and life style factors [14,32-36].

Knowledge, attitude and protective behaviour levels was obviously higher in 16-17 age group in this study compared with younger students, which has been reported to other similar studies [14]. As students get older, increasing the total knowledge levels is rational but most of the students in 18-19 age groups had some more responsibility about their school courses and university entrance exams, so this may have led to less time and lower knowledge [14].

As of our knowledge, this study was designed and performed for the first time in East Azerbaijan, about knowledge, attitude and protective behaviour in high school students. The study enrolled 500 students, and about 95% of them (n=471) participated in this study. Also, the study provided some free educational pamphlets for students for increasing their KAP, acknowledging for participating and taking the time for this study. Most of the students had good (n=332, 70.5%) socio demographic status. This was mostly due to the selection of private schools from the urban areas, and availability of the students.

The limitation of this study was the limited included schools from study region. More comprehensive studies with a larger sample size from all urban and/or rural areas of the region are recommended.

In conclusion knowledge, attitude and protective behaviour regarding cancer has been increased in the high-school students. As family knowledge and attitude is so important in increasing the students’ interests and attitude regarding cancer, so increasing knowledge and attitude at population levels and providing some training courses for students and their families is strongly recommended. It is extremely essential to establish programs and activities that increase awareness among both male and female high-school students and the community at large scales about the main risk factors of cancer, preventional and early diagnostic modalities. Health policy makers should provide additional information about controlling and reducing main cancer risk factors, to help young adolescents to have healthy habits and share their knowledge with population.