|Year : 2014 | Volume
| Issue : 4 | Page : 145-150
Sonographic breast pattern in women in Ibadan, Nigeria
Millicent Olubunmi Obajimi1, Adenike Temitayo Adeniji-Sofoluwe1, Babatunde O Adedokun2, Temitope O Soyemi1, Oku Sunday Bassey1
1 Department of Radiology, Medical Statistics and Environmental Health, College of Medicine, University College Hospital, University of Ibadan, Nigeria
2 Department of Epidemiology, Medical Statistics and Environmental Health, College of Medicine, University College Hospital, University of Ibadan, Ibadan, Nigeria
|Date of Web Publication||7-Oct-2014|
Adenike Temitayo Adeniji-Sofoluwe
Department of Radiology, College of Medicine, University College Hospital, University of Ibadan, Ibadan
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Sonographic breast density pattern like mammography is dependent on the relative proportion of connective and glandular tissue. Breast density is a marker for breast cancer risk and has received wide spread interest in many countries in recent times.
Aims and Objectives: This paper aims at describing the sonographic breast pattern in women in Ibadan using the American College of Radiology in its breast imaging reporting and data system (ACR-BI-RADS) lexicon. It will also estimate the prevalence of the different sonographic breast patterns and attempt to find any association between the breast patterns and various demographic variables in the women studied.
Materials and Methods: A prospective, descriptive study of the sonographic breast pattern in 573 women carried out at the Department of Radiology, University College Hospital, Ibadan. Nigeria. Breasts scans were performed with an Aloka SSD and Logiq P5 machine.
Results: A total of 573 women were recruited into the study. Their age ranged between 14 and 74 years (mean = 38.91 ± 12.51 years and median = 38 years). The modal age group was 30-39 years (26.9%). The women attained menopause between 35 and 59 years (mean = 46.2 ± 5.1 years) while the median age for menopause was 47 years. The majority of the women studied were either obese or overweight (66.9%). Sixty-one (10.6%) women had a positive family history of breast cancer with the heterogeneous fibroglandular (60.7%) breast pattern being commonest in this high risk group; and in the entire study population (52.7%). Significant associations between the sonographic breast pattern, age, menopausal status, parity, body mass index (BMI), and waist-hip ratio (WHR) was found. BI-RADS 2 breast pattern appeared to decrease with increasing age while BI-RADS I breast pattern increased with increasing age (P < 0.001).
Conclusion: Ultrasonography like mammography, can define the parenchymal breast pattern accurately. Strong correlation exists between parenchymal breast pattern and demographic, parity variables, and breast cancer risk factors.
| Abstract in French|| |
Contexte: Modθle de densitι du sein ιchographique comme mammographie est fonction de la proportion relative de tissu conjonctif et glandulaire. La densitι mammaire est un marqueur de risque de cancer du sein et a reηu un large intιrκt de propagation dans de nombreux pays ces derniers temps.
Buts et Objectifs: Ce document vise ΰ dιcrire le modθle du sein ιchographique chez les femmes dans Ibadan en utilisant le lexique ACR-BI-RADS. Il permettra ιgalement d'estimer la prιvalence des diffιrentes formes du sein ιchographiques et tenter de trouver une association entre les motifs du sein et diverses variables dιmographiques dans les femmes ιtudiιes.
Matιriel et Methods: Une ιtude prospective et descriptive de la configuration du sein ιchographique chez 573 femmes menιe au Dιpartement de radiologie, University College Hospital, Ibadan. Nigeria. Seins analyses ont ιtι effectuιes avec un Aloka SSD et Machine Logiq P5.
Rιsultats: Un total de 573 femmes ont ιtι recrutιs dans l'ιtude. Leur βge variait entre 14 ΰ 74 ans [moyenne = 38,91 12,51 et mιdian = 38 annιes]. Le groupe d'βge modal est 30-39 ans (26,9%). Les femmes ont atteint la mιnopause entre 35 et 59 ans (moyenne = 46,2 5,1 ans) alors que l'βge mιdian de la mιnopause est de 47 ans. La majoritι des femmes ιtudiιes ιtaient obθses ou en surpoids (66,9%). Soixante-et-un (10,6%) des femmes avaient des antιcιdents familiaux de cancer du sein avec le motif du sein hιtιrogθne fibroglandulaire (60,7%) ιtant plus frιquente dans ce groupe ΰ haut risque, et dans l'ensemble de la population d'ιtude (52,7%). Des associations significatives entre le modθle, l'βge, le statut, la paritι, l'indice ιchographie mammaire mιnopause masse corporelle et le rapport taille-hanche. Motif du sein BI-RADS 2 semble diminuer avec l'βge alors que BI-RADS motif du sein I augmente avec l'βge (P < 0,001).
Conclusion: L'ιchographie comme la mammographie, permet de dιfinir la configuration du sein du parenchyme prιcision. Forte corrιlation entre les habitudes du sein du parenchyme et dιmographiques, les variables de paritι et les facteurs de risque du cancer du sein.
Mots-clιs: Ιchographie, Femmes, Ibadan, motif du sein, Nigeria
Keywords: Breast pattern, Ibadan, Nigeria, sonography, women
|How to cite this article:|
Obajimi MO, Adeniji-Sofoluwe AT, Adedokun BO, Soyemi TO, Bassey OS. Sonographic breast pattern in women in Ibadan, Nigeria. Ann Afr Med 2014;13:145-50
| Introduction|| |
Whole breast ultrasound is a useful tool for the evaluation of the normal and diseased breast. ,, It is invaluable in tissue characterization and guidance procedures, the former facilitating the description of the breast pattern in female patients. Though its accuracy with respect to diagnosis of breast cancer is not considered to be high enough to be relied upon,  Stavros et al.,  reached high sensitivity for differentiation for benign and malignant breast nodules by sonography. However, the advent of dedicated whole breast sonographic scanners has given sonography a boost. ,,
Sonomammographic breast density pattern like mammography is dependent on the relative proportion of connective and glandular tissue. ,, This breast density is known to be a marker of risk for breast cancer. In the United States of America, ,,, reports show that the African American woman is likely to be diagnosed of an aggressive variant of breast cancer at a much younger age reiterating the reports of Chen et al.,  and Del Carmen et al.,  on the significant impact of race and ethnicity on breast cancer. The question is, do racial differences in the breast density pattern explain these disparities. Expectedly, breast density pattern is a known independent predictor of breast cancer. 
In 2003,  the American College of Radiology in its breast imaging reporting and data system (ACR-BI-RADS) classified the mammographic breast pattern into four BI-RADS categories namely BI-RADS 1 with <25% glandular tissue, BI-RADS 2 with 25-50% glandular tissue, BI-RADS 3 with 51-75% glandular tissue, and BI-RADS 4 with >75% glandular tissue. Conversely, three BI-RADS categories for sonomammography exists.  They are designated as BI-RADS 1: Homogenous fatty, BI-RADS 2: Heterogeneous fibroglandular, and BI-RADS 3: Homogenous fibroglandular breast patterns.
This premier prospective study will provide important local data on the distribution of the various sonographic breast patterns among women in Ibadan according to the sonomammographic ACR-BI-RADS. It will also seek to find any association between these reported patterns and age at study, age at first birth, menopausal status, waist-hip ratio (WHR), and family history of breast cancer.
| Materials and Methods|| |
Five hundred and seventy-three women of different ages who self-presented or were referred by a physician to the breast imaging unit were recruited for this prospective and descriptive study carried out in the Radiology Department of the University College Hospital between 2007 and 2011. This study population included asymptomatic women (screening scans) and those with breast complaints (diagnostic scans), breast scans was performed on women without and with breast complaints. Breast sonographic scans were performed on a General Electric Logiq P5 and Aloka SSD ultrasound Machine using a linear-array, 10 MHz transducer. Informed consent was obtained from all patients; thereafter an assisted questionnaire was administered before a physical examination was performed by the radiologist. Breast ultrasound examination was performed with adjustments made for focal zones, system gain, and time gain compensation settings. The patients were scanned supine in the contralateral posterior oblique position while she positioned her ipsilateral hand behind her head.
The scan was performed in orthogonal planes. On detection of a mass, its location was described using the face of the clock and measured in two planes; lesions were measured in their widest diameter (width) and tallest diameter (height), findings were also characterized using the descriptors in the ACR BI-RADS. Static images of any lesion/abnormality detected during scanning were clearly labeled and recorded/documented.
The axillae were also scanned to evaluate the presence of enlarged lymph nodes; their shape, density, number, size, and vascularity was documented. The sonographic breast density was categorized by the interpreting radiologists M.O and ATS using the ACR sonomammographic breast pattern BI-RADS categories which was converted to numeric values; designated as: BI-RADS 1: Homogenous fatty breast pattern; BI-RADS 2: Heterogeneous fibroglandular pattern; BI-RADS 3: Homogeneous fibroglandular.(10) The reported breast scan was also assigned a final BI-RADS category dependent on overall findings by the radiologists. These are BI-RADS 0: Inconclusive study, BI-RADS 1: Normal/negative study, BI-RADS 2: Benign finding, BI-RADS 3: Probably benign finding, BI-RADS 4: Suspicious finding, BI-RADS 5: Highly suspicious of malignancy, and BI-RADS 6: Known cancer. The ACR Sonomammographic breast pattern BI-RADS lexicon is standardized. Its use makes intra and interobserver variations in the assessment of the breast categories negligible.
Data was entered into Statistical Package for Social Sciences (SPSS) version 17, edited, and analysis carried out. The association between the described sonographic breast pattern and selected sociodemographic and clinical variables were tested using the Chi-square test.
| Results|| |
A total of 573 women were recruited into the study. Their age ranged between 14 and 74 years with a mean age of 38.91 ± 12.51 years and a median of 38 years. The modal age group was 30-39 years (26.9%). The women attained menopause between 35 and 59 years (mean = 46.2 ± 5.1 years), while the median age for menopause was 47 years. Sixty-one (10.6%) women had a positive family history of breast cancer and the predominant breast pattern in this high risk group of women was the BI-RADS 2-heterogeneous fibroglandular pattern (60.7%).
[Figure 1] shows the sonographic breast pattern distribution by the ACR BI-RADS categories in the women studied. The BI-RADS 2 heterogeneous fibroglandular was the most common (52.7%) breast pattern found, while the homogenous fibroglandular breast pattern was least common (14%).
A greater number of women with normal WHR demonstrated the heterogeneous fibroglandular breast pattern (P < 0.001). Women with >4 births were more likely to have the homogenous fatty breast pattern (61.9%) compared with those who had no births (8.2%) (P < 0.001).
Use of oral contraceptives was also divided into two groups namely "ever used" and "never used". BMI was subclassified into the underweight, normal, overweight, and obese groups.
[Table 1] shows the association between selected variables and sonographic breast patterns. The ages of the women was stratified into four groups (<30, 30-39, 40-49, >50 years); parity into three categories (0 birth, 1-3 births, and >4 births) and family history into two; positive and negative family history of breast cancer.
|Table 1: Association of selected variables with sonographic breast patterns|
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[Figure 2] shows the breast patterns by menopausal status. The premenopausal group were more likely to have the heterogeneous breast pattern when compared to the postmenopausal group (P = 0.006).
[Table 2] shows multiple logistic regression analysis of sonographic breast patterns with certain variables. Complete data for 497 women were available for analysis with logistic regression. age, parity, body mass index (BMI), WHR, and menopausal status remained statistically significant independent predictors for the homogenous fatty breast pattern. The odds of having a homogenous fatty breast pattern increased significantly with increasing age, BMI, WHR, and degree of parity.
|Table 2: Multiple logistic regression of sonographic breast patterns on variables|
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There were significant associations between the sonographic breast pattern and age, menopausal status, parity, BMI, and WHR. The proportion of women with the heterogeneous fibroglandular breast pattern appeared to decrease with increasing age while the proportion of homogenous fatty breast pattern increased with increasing age (P < 0.001). The majority of the women studied (66.9%) were either obese or overweight. In the obese population (BMI > 30), the homogenous fatty breast pattern was predominant 5.5%. On the other hand, women who were of normal weight or overweight had the heterogeneous fibroglandular pattern
(50-74.7%). Women with increasing BMI and who were obese (BMI > 30) were more likely to have the homogenous fatty breast pattern (P < 0.001).
| Discussion|| |
In 2003, a standardized lexicon for sonography was developed by the ACR because of an increasing clinical use of sonography.  It was also developed with a similar intent as the mammographic BI-RADS lexicon; to standardize terminology ,,, and facilitate accurate and consistent reporting, interpretation, and communication between clinicians. ,,, Our study clearly demonstrated an inverse correlation between sonographic breast patterns and age, BMI, WHR, parity as well as with menopausal status. A similar inverse correlation was also found in a previous study between these variables and sonographically-defined parenchymal breast patterns.  The sonographic breast pattern showed similar association with age, menopausal status, and parity. These associations resemble those of previous authors. ,,
Mammography has been proven to be of benefit in women especially with the homogenous fatty breast pattern but less promising in those with the homogenous and heterogeneous fibroglandular breast patterns.  The latter breast patterns constituted the majority found in our study in women less than 39. Approximately, 82 and 13% of the women in the less than 30 age group had the heterogenous and homogenous fibroglandular breast patterns, respectively. Stomper et al.,  evaluated the parenchymal density of mammograms in women aged 29-79 years and found 62% of women in their 30 s, 56% of women in their 40 s, 37% of women in their 50 s, and 27% of women in their 60 s with at least 50% parenchymal densities evident on mammography. It is clear that dense tissue is common, especially in younger
Women in the less than 40 age group are not candidates for screening mammography with sensitivity to cancer detection as high as 98.4% in women 50-years-old or older with fatty breasts and 83.7% in women with dense breasts (P = 0.01)  and 81.8% in fatty breasts and 85.4% in dense breasts of women less than 40 years. Kerlikowske et al.,  also found out that in women less than 50-years-old with a family history of breast cancer, mammographic sensitivity decreased to 68.8%. The breast parenchymal patterns have been shown to be markers of varying risk of breast cancer. , A two- to eight-fold relative risk of breast cancer has been reported in women with dense breast when compared with a fatty breast pattern. 
Thus, in women with dense breasts, and particularly those at increased risk because of a family or personal history of breast cancer or atypia, methods to supplement mammography are sought. Sonomammography is therefore an indispensible adjunct to mammography.  No randomized controlled trials have been conducted to evaluate the impact of screening sonography alone on breast cancer mortality rates. A combined detection rate of sonography with mammography has been conducted in randomized controlled trial in Taiwan. The study demonstrated higher detection rate, better performance using mammography; but also indicated the complementary role of ultrasound. This further suggests that the optimal screening modality for young women in an Asian country is to combine mammography with ultrasound.  Also, several single center studies with whole breast bilateral sonography have been shown to depict small nonpalpable invasive breast cancers not seen on mammography, particularly in dense breasts. ,,,,
| Conclusion|| |
Our study clearly demonstrates that ultrasonography like mammography, can define the parenchymal breast pattern accurately. However because of the three categories of ultrasound breast, it is somewhat less reliable in its ability to predict the classification described by Wolfe.  We have also strongly correlated parenchymal breast pattern with demographic and parity variables. These findings are in consonance with other studies ,,, that also show well-established correlations between mammographic breast patterns, demography, and breast cancer risk factors.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]