A simple cyst is a benign finding and requires intervention only for symptomatic relief. Complicated cysts are those which do not fulfill all of the criteria of a simple cyst such as when internal echoes or septations are seen within a cyst or when there is no increased through transmission. These are mostly benign and may not require aspiration. In one series only 1 of 243 lesions (0.4 %) proved malignant; this lesion was 1 of 33 complicated cysts that did not yield fluid [17]. Even when cytology yields atypical cells, the final histology is mostly benign [17]. In a large series of 6,782 cyst aspirations over a 7-year period, the incidence of intracystic papillomas was 5 [0.1 %] [18]. All cases of papilloma showed blood-stained fluid. Overall only 2 % of cyst fluids were blood stained. Cytology of six cases of papilloma was positive in two, negative in two, and falsely positive in two cases [18]. These investigators recommended cytology only when aspirate is blood stained. A cyst that demonstrates thick indistinct walls, thick internal septations, or mixed solid and cystic components requires core biopsy sampling. Clustered microcysts and septate cysts are generally benign [19]. A recently published large series of 5,375 aspirations performed over a 16-year period of noncomplex cysts reported a malignancy rate of 0.3 % [20]. Atypical cytology revealed malignancy in 21 % of cases. All atypical results should undergo further workup. Malignant cytology revealed malignancy in 91 % of cases and hence all patient with malignant histology need to undergo biopsy [20].

Sensitivity of mammography in women with dense breasts has been reported to be as low as 48 % [21]. About 41 % of women may have dense breasts on a mammogram [22]. Increased breast density is an independent risk factor for breast cancer and increased the risk by a factor of 5 [23]. Supplemental ultrasound has been shown to detect additional cancers in women with dense breasts in those with an elevated risk as well in those with an average risk [24–27].

Recently based on these facts and a public campaign undertaken by a breast cancer survivor, several states have passed a law called the “Henda’s law” or the “dense breast law” requiring women with dense breasts to be informed by their clinician about their breast density and discussing the option of undergoing supplemental screening depending on their risk factors.

The ACRIN 6,666 trial showed that 4.2 additional cancers were identified by ultrasound in women with an elevated risk for breast cancer [24]. The dense breast law passed in Connecticut requires notification of women with a greater than 50 % density and recommendation for supplemental screening ultrasound; the law also required insurance to pay for supplemental ultrasound screening. A study from Connecticut looking at such women showed that ultrasound lead to an additional yield of 3.25 cancers per 1,000 in women with dense breasts, normal mammograms, and no additional risk factors [25]. Although the NPV [99.9 %] and sensitivity was very high [96.6 %], the positive predictive value was low at 6.7 % [25]. Yet in another study of 5,519 women with dense breasts who underwent sonographic screening, the supplemental yield was only 1.8 per 1,000 and positive predictive value was low at 5.5 %, and mean tumor size was 9.7 mm [26]. Post enactment of the Connecticut law, a study that looked at women with low risk [614/935], intermediate risk [149/935, 15.9 %], and high risk [87/935, 9.3 %] found one cancer in each of the three groups. All of these three cancers were small solid masses in postmenopausal women for a cancer detection rate of 3.2 per 1,000 women screened again with an expected low positive predictive value of only 6.5 % [27].

About half of the countries that use screening mammography have implemented double reading, although direct evidence of its effectiveness in the context of a national screening program is lacking [28]. Analysis of ten cohort studies showed that overall double reading increases the cancer detection rate by 3–11 per 10,000 women screened and most of the cancers thus found are small cancers. The effect on recall rate depended on the methodology. Double reading with unilateral recall increased the number of women recalled from 38 to 149 per 10,000 women screened. In programs where a consensus or arbitration policy was in place, the recall rate decreased between 61 and 269 per 10,000 women screened [28]. In a large majority of cases, double reads do not lead to disagreement; when there is one mutual consultation, this further diminishes the number of recall. In some facilities cases with disagreement are referred to an arbitration panel. The effectiveness of this methodology of referral to an arbitration panel has been studied. In a series from Netherlands involving screening of 65,779 women, there was concordance in the reads of double readers in 98.7 % of women, and there was agreement on the need for referral in 0.8 % of cases and disagreement on the need for referral in 0.5 % of cases which decreased to 0.3 % after mutual consultation. These 183 studies were referred to the arbitration panel which referred 89 of these for further workup that resulted in a cancer diagnosis in 20/89 [22 %]. Among the 94 cases that were not referred, there were 3 cancers [3 %] at the site of the discrepant mammographic findings [29]. Screening mammograms with discrepant findings form a small but significant subset that may lead to a diagnosis of breast cancer.

Clinical breast examination [CBE] in conjunction with screening mammography can be implemented concurrently when administered in a breast center by a registered nurse or when a screening mammogram is done following a well woman exam as is more often the case. The former has been studied to determine the added benefit of increasing cancer detection. There were 232,515 women in the group receiving CBE and 57,715 in the group undergoing screening mammogram without a clinical breast exam. Sensitivity in the CBE group was 94.9 % vs 88.6 % for the screened group without CBE. However, the false positive was also higher for those women who had CBE with screening mammography compared to those who did not receive CBE [12.5 % vs 7.4 %] [35]. Another large study with dual screening in 300,303 women, CBE increased the rate of detection of small invasive cancer by 2–6 %. Without the concurrent use of CBE, three cancers would be missed for every 10,000 screens [36]. The cost-effectiveness of offering CBE in a comprehensive breast center was reported in a cohort of 60,000 women who received CBE by a nurse practitioner. Four hundred and seventy four had a positive exam leading to a diagnostic evaluation. Forty-six cancers were identified, 32 of which would have been identified by mammography alone, and only 14 were not seen on a mammogram. The cost of CBE was 122,598 per cancer detected based solely on CBE findings [37].

A male breast is composed of subcutaneous tissue, atrophic ducts, and stromal elements with preponderance of fat [38]. Conditions that affect the male breast are therefore related to ductal and stromal proliferation and include the most commonly encountered gynecomastia, invasive ductal carcinoma, and papillary neoplasm. Most commonly men are referred for a breast lump, breast enlargement, or tenderness. Mammography is the initial imaging and may be the only modality needed. If abnormality cannot be imaged on mammography or if findings are questionable, sonography is indicated. The most common cause of breast symptoms are due to gynecomastia.

The term overdiagnosis of breast cancer by screening mammography in population-based studies refers to the difference between cancer detection and subsequent treatment of abnormal findings and the corresponding effect on mortality. The percentage of overdiagnosis represents the estimated percentage of cases that were detected and treated but that would not have affected mortality if had been left alone. In other words mammography identifies cancers that are nonlethal and do not lead to mortality [43, 44]. Bleyer and Belch used a model for expectation values and estimated that 31 % of cancers that are diagnosed breast cancer represent overdiagnosis [43]. They then concluded that the reduction in mortality can be attributed to improvements in therapy and not to early diagnosis [43]. In an opinion article in response to this theory, Gur and Sumkin correctly point out that once a decision to screen is made, the role of a breast imager should be to detect disease early and towards this end due diligence is needed to detect and correctly diagnose all abnormalities at the earliest stage possible. It is then the responsibility of other specialties to make the best use of the information provided by the radiologist to decide how best to use the information in the appropriate management of the patient. They state that there can only be a “correct, partially correct or an incorrect diagnosis and there can only be optimally managed, suboptimally managed and mismanaged and over treated disease” [44]. They go on to appropriately state “There should not be any doubt that the overall objective of a screening program is to first and foremost detect, correctly diagnose, and appropriately treat early preclinical cancers that, if left alone, would become life threatening cancers” [44]. This seems to be a reasonable and appropriate response to the criticism of overdiagnosis of breast cancer.