Mammogram has been the gold standard technique and the mainstay for the detection of breast cancer over decades . Women with the dense breasts meet two major problems, as increased breast density decreases the sensitivity and specificity of mammography owing to a decrease in the contrast between tumor and surrounding breast tissue, and superimposed breast tissues may obscure lesions, resulting in a considerable number of false-negative mammograms. Furthermore, the dense breast itself is a risk factor for developing breast cancer . Tomosynthesis has evolved as advanced imaging technique for early diagnosis of breast lesions with a promising role particularly in dense and treated breasts . Digital breast tomosynthesis provides 3D imaging of the breast, so it reduces the superimposition of breast tissue and improves cancer detection. Previous studies showed that DBT improved the sensitivity, specificity, and accuracy of full-field digital mammography by reducing the recall rate and increasing the cancer detection rate .
In the current study, we compared the performance of digital breast tomosynthesis with the performance of FFDM in all breast densities at different age groups. We observed that digital breast tomosynthesis was superior to FFDM in the detection and characterization of different breast lesions in correlation with the final diagnosis. We also observed improvement in the overall diagnostic capability by adding DBT to FFDM. Sensitivity of lesion detection by DBT was 100% compared to 64.44% by FFDM, specificity 97.77% by DBT compared to 77.78% by FFDM, positive predictive value 97.78% by DBT compared to 74.63% by FFDM, negative predictive value 100% by DBT compared to 68.63% by FFDM, and a diagnostic accuracy 97.7% by DBT compared to 71.11% by FFDM.
Our results were comparable to prior studies done by Conant et al. , Skaane et al. , and Divya et al.  who reported increased sensitivity, specificity, and increased cancer detection when DBT was used. Skaane et al. found increase sensitivity from 54.1 to 70.5% and mild increase in specificity from 94 to 95% by using DBT compared to digital mammography . While Divya et al. showed that sensitivity increased from 83.6 to 100%, also specificity increased from 38.7 to 87.77% and positive predictive value raised from of 56 to 81.67% after adding DBT to FFDM .
In this current study, we observed that 52/90 (57.7%) of cases demonstrated a discrepancy between FFDM and DBT in BIRADS scoring. By adding DBT to FFDM, 13 cases were upgraded from BIRADS I to IV by discovering spiculated lesions and/or architecture distortion in DBT proved by US examination and histopathology were not seen in mammography as patients were with high-density breasts. Another 14 cases were upgraded from BIRADS I to III by discovering well-defined lesions on tomosynthesis proved by the US to be cysts, fibroadenomas, and/or intramammary LNs which could not be seen at mammography by the effect of overlapping breast tissue in the dense breast. Four cases were upgraded from BIRADS III to IV detected at mammography as well defined masses, yet discovering speculation, indistinct border, and/or architecture distortion in tomosynthesis as it reduces the superimposition of the breast tissue and proved by the US examination and histopathology to be IDC. Also 12 cases were upgraded from BIRADS IV to V by finding frank speculation and dense rounded lymphadenopathies proved by US and histopathology to be IDC.
In seven cases, BIRADS scoring were downgraded from IV to II and III by observing a well-defined border by tomosynthesis, which minimizes the effect of tissue overlap and allows better visualization of the masses reported as of indistinct border by mammography. US examination proved them well-defined cysts and/or fibroadenomas. Two cases were downgraded from BIRADS IV to I by proving no evidence of the architecture distortion reported by mammography in DBT and proved by the US examination.
In thirty-eight cases, DBT did not change the BIRADS scoring, but its addition increased the conspicuity of the lesions detected and diagnostic confidence.
Our results were comparable to a study performed by Divya et al. , which conducted a comparison between DBT and FFDM according to the BIRADS scoring. With the addition of tomosynthesis to FFDM 53% of the cases changing their BIRADS scoring, BIRADS was upgraded in 14% and downgraded in 31% of cases and DBT did not change the BIRADS scoring in 47% of cases but its addition increased the diagnostic confidence.
In our study, we noticed the change in BIRADS scoring was detected mainly in patients with dense breasts. As patients with high breast densities (ACR c and d), 61% of cases had changed their BIRADS scoring (49% of cases had upgraded and 12% of cases had downgraded) with the addition of tomosynthesis and 39% of cases had no change in BIRADS scoring (P value 0.04). Yet, in patients with fatty and fibro-glandular breast densities (ACR a and b), 30% of cases had upgraded and 15% of cases had downgraded BIRADS scoring with the addition of tomosynthesis with 55% of cases had no change in BIRADS scoring (P value 0.3).
The results of our study are comparable with the study of Østerås et al. . He said that adding DBT to FFDM yields more speculated masses or architectural distortions in women of all density categories with P value < .001 in women with scattered fibro-glandular and heterogeneously dense breasts and P value > .05 in women with almost entirely fatty and extremely dense breasts.
As reported in several earlier studies, evidence suggests that the sensitivity and specificity of mammography decreased in the breasts with a higher density. In our study, the sensitivity of FFDM in dense breasts (ACR c and d) is 76.7% compared to 84.5% in non-dense breasts ACR (a and b), yet DBT had a sensitivity of 100% in both dense and non-dense breasts. The specificity of FFDM in the dense breasts was 70.5% compared to 83.6% in non-dense breasts, yet DBT had a specificity of 97.7% in dense breasts and 100% in non-dense breasts.
Chiu et al.  reported in their study about the effect of breast density on breast cancer incidence and screening. The sensitivity of mammography was 62.8% in dense breasts as compared to 82% in non-dense breasts and a drop in specificity was reported to be 89.6% in dense breasts as compared to 96.5% in non-dense breasts.
Phi et al.  and Asbeutah et al.  performed a meta-analysis on tomosynthesis in dense breasts for screening and diagnosis. They concluded that DBT increased sensitivity and the cancer detection rate in screening and diagnosis in comparison to mammography alone.
In our study, we noticed that DBT detected more breast masses than did FFDM. DBT detected new lesions in 22 cases especially in patients with dense breasts (ACR c and d) and allows better visualization and evaluation of lesions margins.
Our results supported by the literature of Conant et al.  in their study about digital breast tomosynthesis vs digital mammography in cancer detection and recall rates in different ages and breast densities. He concluded that screening with DBT simultaneously improved breast cancer detection while reducing false-positive recalls which were significant across all age groups and breast densities categories. Invasive cancers detected by DBT were more likely smaller and node-negative compared with cancers detected by digital mammography, particularly in women aged 40 to 49 years.
Rafferty et al.  performed a study that included digital mammography alone and digital mammography plus tomosynthesis for breast cancer screening in the dense and non-dense breasts. They concluded that adding tomosynthesis to digital mammography leads to an increase in cancer detection rate and reduction in recall rate more obvious in women with heterogeneously dense breasts than in those with non-dense breasts or extremely dense breasts.
In our study, we discovered that in patients of the age group 30–40 years (complaining of breast masses or for screening for breast cancer due to 1st-degree relative positive for breast cancer), 61.5% had changed their BIRADS scoring with the addition of DBT (P value 0.02). In patients of age group 41–50 years, 50% of cases changed BIRADS scoring with the addition of tomosynthesis (P value 0.07). Yet, in patients of age group 51–60 years, 61.5% of cases had no change in BIRADS scoring (P value 0.08), and patients in the age group of 61–70 years, 85% of cases had no change in BIRADS scoring with the addition of DBT but increased diagnostic confidence (P value 0.8).
The sensitivity of FFDM in pts. < 50 years is 54.15% compared to 84.2% in pts. > 50 years (as most patients below 50 years were female had dense breast or on hormonal contraceptive method) with sensitivity of DBT 100% in both. The specificity of FFDM in pts. < 50 years is 76.5% compared to 88.6% in pts. > 50 years with a specificity of DBT in pts. < 50 years and 96.31% compared to 100% in pts. > 50 years.
The study of Østerås et al.  was comparable to our results which concluded that the results of DBT were higher for all age strata compared to FFDM. Improvement in the true-positive rate and decrease in false-positive interpretations with P = .008 for ages less than 50 years, P = .02 for ages 51–59 years, and P = .001 for ages 60–64 years.
We noticed in our study that there is a 33% reduction in recall rate after adding tomosynthesis compared to FFDM alone. We observed that across all breast densities and patient ages with statistical significance in all subgroups except in patients with predominantly fatty breast density and patients older than 60 years. Patients receiving the greatest benefit were women with dense breasts (ACR c and d) and those younger than 50 years.
The aforementioned results were in keeping with Haas et al. who concluded that recall rates were much lower in patients who underwent tomosynthesis plus conventional mammography than in those who underwent conventional mammography alone with a 30% reduction in recall rate overall.
Divya et al.  concluded that the most significant decrease in recall rates was due to a reduction in false-positive patients. Combination of the two modalities leads to reduction in BIRADS in 31% of patients with a significant decrease in recall rates seen in ACR categories b, c, d, and age groups < 40 years due to improved sensitivity, specificity, positive predictive value, and reduced false-positive value.
The study done by Lowry et al.  has a comparative effectiveness study between the performance of tomosynthesis vs digital mammography in community practice by patient age, screening round, and breast density. They concluded that both recall and cancer detection rates improved using digital breast tomosynthesis vs digital mammography for women aged 40 to 79 years with heterogeneously dense breasts and for women aged 50 to 79 years with scattered fibro-glandular density; by contrast, the performance was similar in women with extremely dense breasts.
In our study, we found that FFDM is superior to DBT in detection calcification with a sensitivity of DBT 16% lower than FFDM. However, the results of the synthetic 2D image are matching with that of FFDM.
Spangler et al.  in their study said that FFDM appears slightly more sensitive than digital breast tomosynthesis for the detection of calcification. However, diagnostic performance using BI-RADS was not much different.
According to the results of our study, we recommend tomosynthesis as the 1st step diagnostic and screening tool instead of mammography in young females below 40 years and in females with proposed dense breast as on hormonal therapy or hormonal contraception, which may have a favorable risk to benefit ratio.
Tomosynthesis proved to be of higher sensitivity and specificity than FFDM in all breast densities, especially dense breasts. It has the advantages of three-dimensional data, which helps in eliminating the overlap of tissues seen in two-dimensional images of mammography with better resolution of the internal breast contents leading to better diagnostic capabilities. This in turn would reduce false-positive results, unnecessary recalls, and the need for additional time-consuming imaging such as special mammographic views, thereby increasing the efficacy of DBT by reducing the additional radiation dose, time, and money.