The variety of newly recognized breast most cancers instances and associated deaths is the very best amongst feminine malignancies in practically all international locations1. The estimated annual proportion change in mortality elevated by a median of 0.29% to 0.75% per yr from 1990 to 2019 in low- and middle-Social Demographic Index (SDI) international locations. In distinction, the estimated annual proportion change in mortality decreased by a median of 1.52% per yr in excessive SDI international locations2 as a result of early prognosis and therapy. Most East Asian international locations haven’t seen proof of a discount in breast most cancers mortality1.
The Worldwide Company for Analysis on Most cancers Working Group advocate mammography (MG) as the first screening technique. Nonetheless, breast most cancers screening utilizing MG could be a problem in locations the place MG items and skilled professionals are unavailable. The scarcity of machines and radiologists limits the implementation of MG-based breast most cancers screening packages in some low-resource international locations. Moreover, the sensitivity of MG decreases from 86% in girls with near-entire fatty breasts to 61% in girls with extraordinarily dense breasts3. Asian girls sometimes have denser breasts. To handle the issue of false-negative MG in East Asian international locations, ultrasound has gained broad utilization. Automated breast ultrasound (ABUS) standardizes the picture acquisition process in comparison with hand-held ultrasound (HHUS). Subsequently, ABUS is taken into account extra goal, making ABUS a promising various to each HHUS and MG for breast most cancers screening.
We reviewed the present standing of breast most cancers screening to establish the limitations to implementing breast most cancers screening. We additionally summarized the proof on utilizing HHUS and ABUS for breast most cancers screening to reveal the feasibility and scientific validity of performing HHUS- and ABUS-based breast most cancers screening in Asian international locations.
Proof on utilizing HHUS for breast most cancers screening
HHUS as a supplementary technique
The sensitivity of the take a look at and participation charge are thought-about two foremost components influencing the screening impact on breast most cancers mortality. A number of prior research reported elevated breast most cancers detection when utilizing HHUS as a supplementary technique to MG amongst girls with dense breasts or girls at an elevated danger of creating breast most cancers4,5. Frequent methods for integrating HHUS into breast most cancers screening embody utilizing HHUS for girls with adverse MG outcomes and all girls no matter MG outcomes. HHUS detected a further 4.90 cancers per 1,000 screens, which was considerably greater than tomosynthesis (2.83 cancers per 1,000 screens)4. Combining MG with HHUS, no matter MG outcomes, considerably elevated most cancers detection charges in high- and average-risk girls. Nonetheless, this method is related to elevated false-positive findings and recall charges. As an alternative of including HHUS for all girls with adverse MG outcomes, Dong et al. concluded that adjunctive HHUS ought to solely be really helpful for girls who had been labeled as breast imaging reporting and knowledge system (BI-RADS) 0–2 by MG however not for girls labeled as BI-RADS 3. Dong et al. additionally concluded that adjunctive HHUS needs to be really helpful for girls with BI-RADS 0–2, not just for girls with dense breasts but additionally girls with a historical past of benign breast illness (Table 1)6.
Abstract of screening effectiveness of HHUS, ABUS, and MG
The results of MG plus HHUS in girls with non-dense breasts are inconsistent throughout completely different research. Nakamura et al. reported no important distinction in most cancers detection and recall charge between girls who underwent MG alone and ladies who underwent MG plus HHUS7. Nonetheless, Harada-Shoji et al. reported that MG plus HHUS had larger sensitivity in girls with dense and non-dense breasts8.
HHUS as the first screening technique
A pooled evaluation of 11 joint screening research indicated that HHUS, as a major screening technique, carried out comparably to MG alone with respect to sensitivity, specificity, most cancers detection charge, biopsy charge, and the proportion of node-negative cancers amongst screening-detected invasive cancers. Nonetheless, HHUS had the next detection charge for invasive cancers9. Furthermore, in comparison with MG, HHUS alone detected extra breast cancers throughout all age teams with the impact being extra pronounced amongst girls < 50 years of age (< 50 years: 77.4% vs. 50.6%, P < 0.001; > 50 years: 70.4% vs. 65.9%, P < 0.001)10. Nonetheless, breast most cancers detection charges with HHUS had been additionally similar to MG (52.3% vs. 53.2%) in high-risk Caucasian girls, though HHUS detected extra invasive and node-negative breast cancers than MG11.
A number of cross-sectional, observational, and potential research carried out in China reported that HHUS is a extra delicate technique for breast most cancers detection in Chinese language girls. Research carried out in high- and average-risk Chinese language girls revealed that major HHUS detected extra breast cancers than MG, particularly in girls with dense breasts. An actual-world examine carried out in Beijing, China confirmed that HHUS for major screening adopted by MG for triage or combining each HHUS and MG had considerably larger sensitivity in comparison with HHUS alone or MG as major screening adopted by HHUS for triage in high-risk girls (Table 1)12.
Better than 50% of Chinese language girls have heterogeneous or extraordinarily dense breasts, which is considerably larger that Caucasian counterparts. Consequently, ultrasound is more and more thought-about an efficient various for personalised breast most cancers screening in these geographic areas. Extra importantly, HHUS has the flexibility to detect extra breast cancers at an early stage11,13. International locations that achieved a 2% annual discount in breast most cancers mortality charges recognized at the very least 60% of instances in levels I and II, which was aligned with one of many targets established by the International Breast Most cancers Initiative (GBCI) launched by the World Well being Group. Ohuchi discovered that 78% of breast most cancers instances detected utilizing HHUS alone had been in scientific levels 0–I13. This highlights the potential of adopting HHUS screening to fulfill the GBCI targets for breast most cancers management.
ABUS proof for breast most cancers screening
HHUS is operator-dependent and lacks reproducibility, which limits use of HHUS in medical resource-constrained areas with out skilled radiologists or physicians. In contrast to HHUS, ABUS is user-independent and separates picture acquisition from interpretation, which allows further comparability or evaluation. These options are anticipated to facilitate the institution of an imaging interpretation heart, growing the screening accuracy and standardizing the screening process with the increasing utilization of ABUS in screening actions.
Research evaluating ABUS screening efficiency have principally been carried out amongst asymptomatic girls. Like HHUS, including ABUS to MG in girls with dense breasts elevated the invasive breast most cancers detection charge in a number of potential research carried out in asymptomatic girls. Whereas no distinction in tumor measurement was existed in cancers detected by ABUS and MG within the Gatta examine14, Kelly famous that joint screening with ABUS and MG doubled the breast most cancers detection charge in girls with dense breasts (3.60 to 7.20 per 1,000 screens). ABUS detected invasive breast cancers that had been smaller in measurement. An observational screening examine with a bigger pattern measurement reported comparable outcomes to Kelly, however with a smaller enhance in most cancers detection (5.40 to 7.30 per 1,000 screens)15. In a examine involving Chinese language asymptomatic girls revealed that ABUS sensitivity alone was larger than MG with no loss in specificity. These variations had been extra pronounced in girls with dense breasts however not statistically important in girls with non-dense breasts16. When used as a supplementary technique for girls with adverse MG outcomes and dense breasts, ABUS plus MG detected 99.1% of breast cancers in Chinese language girls (Table 1)17.
Few research have evaluated the effectiveness of ABUS within the screening settings. In a retrospective examine, ABUS confirmed comparable screening efficiency to earlier screening leads to scientific settings. Potential research evaluating ABUS as the first screening technique for breast most cancers in screening settings in East Asian girls have proven excessive sensitivity and specificity. Amongst Korean girls, the sensitivity of ABUS alone was 83.3% and the specificity was 90.7%18. Amongst Chinese language girls aged 45–54 years with dense breasts, including ABUS to MG detected a further 0.83 cancers per 1,000 screens, considerably greater than MG alone. Nonetheless, no important variations had been noticed in girls aged 55–64 years or these with non-dense breasts19.
Well being system traits, together with breast most cancers early detection packages, breast most cancers early detection pointers, nationwide most cancers plans, breast most cancers referral techniques, and pathology companies, are extra developed in high-income international locations (HICs) than low-income international locations (LICs), which results in disparities in breast most cancers mortality between these international locations. Practically 68% of LICs lack breast most cancers early detection packages or pointers and 60% haven’t any breast most cancers referral techniques20. Breast most cancers screening and early prognosis initiatives have been applied on the provincial or institutional stage in most Asian international locations, a few of which implement ultrasound and/or scientific breast examination (CBE) with MG-based screening packages. To handle these gaps, pragmatic approaches to well being system strengthening inside a resource-stratified framework are important to enhance breast most cancers care. Institution of an imaging interpretation heart and integration of synthetic intelligence (AI) system into ABUS screening is anticipated to extend screening high quality and lengthen protection in areas with out professionals.
Issues with HHUS and ABUS use for breast most cancers screening
Excessive false-positive and recall charges are the principle considerations relating to adjunct screening with ABUS or HHUS as a result of additional examination is required in girls with constructive screening outcomes by MG or ultrasound. Implementing an built-in evaluation system that mixes MG with adjunctive ultrasound might probably handle this difficulty. In such a system, adjunctive ultrasound is utilized based mostly on MG findings and the ultimate class is determined by the evaluation of mixed MG and ultrasound to scale back pointless remembers. Chinese language researchers proposed risk-based BI-RADS evaluation standards to enhance the diagnostic effectivity of HHUS. Particularly, the Gail mannequin was mixed with BI-RADS classes to switch the ultimate BI-RADS classes in accordance with the person danger stage calculated utilizing the Gail mannequin. The mixed sensitivity, specificity, constructive predictive worth, adverse prediction worth, and AUC had been 95.6%, 91.3%, 85.0%, 97.6%, and 97.6%, respectively21. A danger prediction mannequin might be included with HHUS and ABUS sooner or later to extend screening accuracy and scale back pointless biopsies.
The time-consuming nature of ABUS poses a priority when adopting ABUS for mass screening. Brunetti et al. in contrast the picture acquisition and interpretation occasions of ABUS to HHUS. Brunetti et al. reported that the common time to carry out and browse photos was 5 min for HHUS and 17 min for ABUS. Moreover, roughly 60% of the time was spent on ABUS execution and the remaining 40% was spent on picture interpretation. Nonetheless, the ABUS examination time decreased as technologists turned extra acquainted with the method. Beforehand, producers really helpful three-view scanning for all girls, whereas four-view scanning was recommended for girls with giant breasts. Breast protection was passable in 94.1% and 91.9% of ladies with small breasts with two- and three-view scanning, respectively. As well as, there was no distinction in sensitivity and specificity between two- and three view-scanning22. Scanning and studying occasions diversified relying on the variety of views. Subsequently, choosing two-view scanning for population-based breast most cancers screening could be a possible and time-saving technique for many Asian girls who’ve small breasts (Table 1).
Research evaluating screening efficiency of ABUS had been principally carried out amongst asymptomatic girls in research with small pattern sizes or in retrospective screening research. The dearth of large-scale potential randomized scientific trials evaluating the effectiveness of ABUS alone in screening settings restricted the robustness of the proof and hindered definitive conclusions relating to the scientific utility and impression on breast most cancers outcomes. Furthermore, the long-term screening impact of HHUS or ABUS on breast most cancers mortality stays unclear as a result of inadequate follow-up in earlier research. The five-year survival charge of ultrasound-detected breast most cancers was reported to be practically 98% with a median follow-up of seven years in Korea23. As an alternative of extending the follow-up interval of current research, modeling research might be used to estimate the impression of ultrasound screening on breast most cancers mortality.
Adapting a screening technique based mostly on danger
Threat-based screening has grown considerably lately as a result of population-based screening is probably not essentially the most environment friendly use of assets. Quite a few observational and modeling research have proven that personalised screening is cost-effective. Breast density-stratified screening, which entails altering screening intervals fairly than including supplemental strategies, has been confirmed cost-effective for girls at common danger of breast most cancers. Incorporating supplemental screening based mostly on the chance of masking as a result of excessive breast density requires further assets and will scale back cost-effectiveness. In distinction, figuring out high-risk girls for adjusted screening approaches and adopting fewer intensive methods for girls at decrease danger has confirmed to be cost-effective24. The principle components included within the danger prediction fashions are age, breast density, household historical past, and former biopsies, with some fashions additionally incorporating genetic data. Nonetheless, the web well being profit will depend on the actual risk-stratification technique and extra research are warranted to evaluate newer risk-stratification applied sciences, particularly these specialised for the Asian inhabitants.
Other than mammographic breast density, which is calculated because the proportion of dense breast tissue (together with glandular and stromal), restricted or absent lobular involution has been independently related to the next danger of creating breast most cancers. The glandular tissue part, which displays the extent of lobular involution, could be distinguished by HHUS and ABUS and has been reported to be independently related to breast most cancers danger25. Subsequently, utilizing HHUS- and ABUS-adjusted breast density measurement may enhance breast most cancers danger prediction.
Future views
A number of key areas require additional exploration to optimize the mixing of HHUS and ABUS into nationwide screening packages. First, large-scale potential randomized scientific trials are wanted to guage the long-term effectiveness of HHUS and ABUS in lowering breast most cancers mortality. Modeling research might complement these trials to estimate the impression on inhabitants well being outcomes.
Second, the mixing of AI into HHUS and ABUS interpretation holds nice potential to reinforce diagnostic accuracy, scale back studying occasions, and decrease false-positives. AI-assisted imaging interpretation facilities might assist broaden entry in geographic areas with restricted radiologic experience. Warning needs to be exercised when integrating AI into screening actions with a robust emphasis on rigorous analysis and cautious consideration of the position of those rising applied sciences.
Third, personalised, risk-based screening approaches needs to be additional developed and validated for the Asian inhabitants. Incorporating HHUS- and ABUS-adjusted breast density measurement could enhance breast most cancers danger prediction and screening effectivity. Value-effectiveness analyses also needs to information the implementation of tailor-made screening methods to make sure resource-efficient deployment in numerous healthcare settings.
Lastly, pragmatic approaches to well being system strengthening are essential, particularly in resource-limited settings. Establishing sustainable screening packages, enhancing coaching for healthcare professionals, and enhancing infrastructure for imaging interpretation can be important steps towards closing the hole in breast most cancers outcomes between high- and low-resource areas. By addressing these challenges, ABUS might have a transformative position in reaching the GBCI targets and in the end lowering breast most cancers mortality worldwide.
Battle of curiosity assertion
No potential conflicts of curiosity are disclosed.
Creator contributions
Conceived and designed the evaluate: Huijiao Yan, Daehee Kang, Youlin Qiao
Collected the info: Huijiao Yan, Qiankun Wang
Wrote the paper: Huijiao Yan, Qiankun Wang
Reviewed and revised the paper: Fanghui Zhao, Youlin Qiao, Daehee Kang.
- Obtained December 4, 2024.
- Accepted March 4, 2025.
- Copyright: © 2025, The Authors
