The mean age (SD) of participants was 47.63 (10.46) years and the majority of individuals were at age 35-49 years (61.5%) and the minority (7.1%) was at age 65-85 and the rest were at age of 50-64 years. The majority of women were at an educational level of high school or higher (81.0%) and housewife (74.1%). A few participants (7%) had a family history of breast cancer in first-degree relatives. Almost, 84.9% were married and 6.6% single and the remainders were either divorced or widow (8.5%). About half of participants had a low level of knowledge of breast cancer risk factors and 34.8% had a low level of awareness of signs and symptoms of breast (Table 1). Table 2 shows that the mean of self-reported perceived 5-year risk and lifetime risk was significantly higher than actual risk (9.19±16.1 vs. 0.89± 0.89, p=0.001, and 14.87 ±20.79 vs. 8.87± 3.84 vs p=0.01 respectively). While the median of perceived risk was rather lower than actual risk (0% vs 0.7%, and 5.0% vs. 8.3%). But the third quartile (Q3) of perceived risk much greater than the actual risk for both 5-year and lifetime risk. Table 3 indicates that among participants with low or average 5-year risk for disease, roughly 45.7% of women, their perceived risk was over-estimated. While among high risk, 54.1% of participants under-estimated in their perceived risk. Based on the objective/actual 5-year risk assessment (Gail criteria) 61 women (7.5%) were at high risk. In contrast, for perceived risk with a similar cutoff value was 366 (45.8%). This also shows that higher level 5-year perceived risk compared to the actual risk for BC. The Kappa statistics across data in Table 3 show that there is no agreement between perceived risk and actual risk (Kappa=0.00, p=0.98).
Table 1. Characteristics of study subjects
Characteristics
|
N (%)
|
Age (year)
35-49
50-64
>=65
|
492 (61.5)
251 (31.4)
57 (7.1)
|
1st menstrual age (year)
<12
>=12
|
119(15.1)
667(84.9)
|
Age at 1st birth (year)
<20
20-24
25-29
≥30
|
249 (33.2)
317(42.3)
141 (18.8)
43 (5.7)
|
Breast cancer at 1st degree of relatives
No
Yes
|
742 (93.0)
58 (7.0)
|
No of biopsy
None/not applicable
≥1
|
744 (93.0)
56 (7.0)
|
Education
Illiterate
Primary
High school
University
|
78 (9.8)
154 (19.3)
393 (49.1)
175 (21.9)
|
Occupation
Housewife
Employee
Retired
|
593 (74.0)
175 (21.9)
32 (4.0)
|
Marital status
Single
Married
Divorced/Widow
|
53 (6.6)
679 (84.9)
68 (8.5)
|
Knowledge of risk factor
Low
High
|
419 (52.6)
377 (47.4)
|
Awareness of signs and symptoms of BC
Low
High
|
275 (34.8)
516 (65.2)
|
Table 2. The mean (SD) and the quartiles of self- perceived risk and estimated actual risk of women BC development in study sample
|
Perceived 5-year risk
|
Perceived lifetime risk
|
Actual 5-year risk
|
Actual lifetime risk
|
Mean (SD) %
|
9.19 (16.1)
|
14.87 (20.79)
|
0.89 (0.89)
|
8.87 (3.84)
|
Q1 %
|
0.00
|
0.00
|
0.50
|
6.82
|
Q2 (Median) %
|
0.00
|
5.00
|
0.70
|
8.30
|
Q3 %
|
10.00
|
20.00
|
1.10
|
10.30
|
Table 3. The self-perceived 5-year risk of BC development according to corresponded estimated actual 5-year risk˦
Perceived 5-year risk
|
Actual 5-year risk
|
All
|
<1.66% risk
|
≥1.66% risk
|
<1.66%
|
401 (54.3)
|
33 (54.1)
|
434 (54.3)
|
≥1.66%
|
338 (45.7)
|
28 (45.9)
|
366 (45.8)
|
All
|
739 (100)
|
61(100)
|
800 (100)
|
Kappa=0.00; p=0.98
˦The data show the frequencies and percentage in the parenthesis.
Table 4 shows that women at high lifetime risk, 44.0% times under-estimated their risk while low or average-risk subjects, 45.0% of times over-estimated their risk in BC development. Based on actual lifetime risk, 225 (28.1%) subjects were labeled as high risk but this figure for perceived risk was 385 (48.1%) individuals. The Kappa statistics were 0.09 (p=0.005) which shows a low level of agreement between perceived risk and actual risk (Kappa=0.09, p=0.005).
Table 5 also presents that among women with low/average risk, the percentage of over-estimate of perceived risk was significantly higher among younger (p=0.05), the high level of knowledge of risk factors (p=0.002) and symptoms & signs (p=0.004) were associated with the higher education level (p=0.04). While in a high-risk group, the data did not show a clear pattern of under-estimate of perceived risk with individuals’ characteristics.
Table 4. The self-perceived lifetime risk of BC development according to corresponded estimated actual lifetime risk˦
Perceived lifetime risk
|
Actual lifetime risk
|
All
|
<10% risk
|
≥10% risk
|
<10%
|
316 (55.0)
|
99 (44.0)
|
415 (51.9)
|
≥10%
|
259 (45.0)
|
126 (56.0)
|
385 (48.1)
|
All
|
576(100)
|
225 (100)
|
800 (100)
|
Kappa=0.09; p=0.005
˦The data show the frequencies and percentage in the parenthesis.
Table 5. The distribution of over-estimate and under-estimate with respect to individuals’ characteristics of women among low/average risk and high risk groups
Characteristics
|
Low/average risk
(n=739)
|
|
High risk
(n=61)
|
|
Accurate
n (%)
|
Over-estimate
n (%)
|
p-value
|
Accurate
n (%)
|
Under-estimate
n (%)
|
p-value
|
Age group (year)
35-49
50-64
relatives≥65
|
241(49.9)
125(56.8)
24(66.7)
|
242(50.1)
95(43.2)
12(33.3)
|
0.05
|
3(33.3)
14(45.2)
11(52.4)
|
6(66.7)
17(54.8)
10(47.6)
|
0.63
|
Breast cancer at 1st degree relatives
None
Yes
|
376(53.0)
14(48.3)
|
334(47.0)
21(51.2)
|
0.62
|
16(47.1)
12(44.1)
|
18(52.9)
15(55.6)
|
0.84
|
No of biopsy
None
≥1
|
370(53.0)
20(48.8)
|
328(47.0)
21(51.2)
|
0.59
|
20(45.5)
8(47.1)
|
24(54.5)
9(52.9)
|
0.91
|
Knowledge of risk factors
Low
High
|
221(58.3)
167(46.9)
|
158(41.7)
189(53.1)
|
0.002
|
20(50.0)
8(38.1)
|
20(50.0)
13(61.9)
|
0.37
|
Knowledge of symptoms & signs
Low
High
|
155(59.8)
230(48.8)
|
104(40.2)
241(51.2)
|
0.004
|
5(31.2)
23(51.1)
|
11(68.8)
22(48.9)
|
0.17
|
Education
Illiterate
Elementary
High school
University level
|
47(69.1)
78(53.1)
182(50.3)
83(51.2)
|
21(30.9)
69(46.9)
180(49.7)
79(48.8)
|
0.04
|
6(60.0)
2(28.6)
14(45.2)
6(46.2)
|
4(40.0)
5(71.4)
17(54.8)
7(53.8)
|
0.65
|
Occupation
Housewife
Employee
Retired
|
292(52.7)
93(55.4)
5(29.4)
|
292(47.3)
75(44.6)
12(70.6)
|
0.12
|
18(46.2)
4(57.1)
6(40.0)
|
21(53.8)
3(42.9)
9(60.0)
|
0.75
|
1st menstrual age
<12 y
≥12
|
48(45.3)
335(54.0)
|
58(54.7)
285(46.0)
|
0.09
|
7(53.8)
20(42.6)
|
6(46.2)
27(57.4)
|
0.47
|
The p-values were calculated using Chi-square test.
Table 6 and Figure 1 in panel (a) and (b) display the corresponded accuracy and the location of ROC curves of perceiving risk in the prediction of actual 5-year and lifetime risk. The AUCs were 0.53 (95%CI: 0.44- 0.61; p=0.47) and 0.58 (95%CI: 0.54-0.62, p=0.001) for perceived risk in prediction of actual 5-year risk and lifetime risk respectively. The perceived risk has appeared with very low sensitivity and specificity (Sen=45.9% and Sp=54.3% for 5-year risk and Sen=56%, Sp=55% for lifetime risk). These findings also show the low performance for accuracy of self-perceived risk on VAS in the prediction of the actual risk. Additionally, the perceived risk in VAS yielded low performance in positive predicted value (PPV) but relatively high in negative predicted value (NPV).
Table 6. The performance of accuracy of self-perceived risk in BC development compared with actual risk
Perceived risk
|
AUC (95%CI)
|
p-value
|
Sen
(%)
|
Sp
(%)
|
PPV (%)
|
NPV
(%)
|
5-year risk
|
0.53 ( 0.44-0.61)
|
0.47
|
45.9
|
54.3
|
7.6
|
92.4
|
Lifetime risk
|
0.58(0.54-0.62)
|
0.005
|
56.0
|
55.0
|
32.7
|
76.1
|
AUC: area under the curve; Sen: sensitivity; Sp: specificity; PPV: positive predicted value; NPV: negative predicted value