Screening mammography has led to decreased breast cancer-specific mortality, and both digital mammography (DM) and digital breast tomosynthesis (DBT) are available modalities. A study by Lowry and colleagues evaluated DM and DBT performance in over 1,500,000 women age 40-79 without a prior history of breast cancer and demonstrated greater DBT benefit on initial screening exam. DBT benefit persisted on subsequent screening for women with heterogeneously dense breasts and scattered fibroglandular density, while no improvement in recall or cancer detection rates was seen for women with extremely dense breasts with DBT on subsequent exams. A physician survey showed 30% utilization of DBT, with higher uptake in academic settings and those with higher number of breast imagers and mammography units. Interestingly, 16% of respondents used mammographic density as a criterion to select patients to undergo DBT. Guidelines to help determine which women benefit from DBT would be a useful asset to clinicians and help optimize resources.
Although the majority of breast cancers are detected by screening mammography, a significant proportion are first noticed by a patient. Interval breast cancers, those detected between a normal mammogram and next scheduled mammogram, have more unfavorable features and worse survival compared with those detected by screening . Niraula et al found that interval breast cancers accounted for approximately 20% of cases, were over 6 times more likely to be higher grade, nearly 3 times more likely to be estrogen receptor-negative, and had a hazard ratio of 3.5 for breast cancer-specific mortality compared to screening-detected breast cancers. These findings are not entirely surprising as tumors with more aggressive biology are expected to have a faster onset and progression. Development of more personalized screening strategies may help address breast cancer heterogeneity.
Breast cancer diagnosed in women ≥70 years of age tends to be early stage and hormone receptor (HR)-positive. These cancers carry an excellent prognosis, and omission of routine sentinel lymph node biopsy (SLNB) and post-lumpectomy radiotherapy (assuming endocrine therapy is given) are acceptable strategies. However, these modalities are still utilized at fairly high rates nationally. Wang and colleagues conducted a qualitative study in women ≥70 years of age without a diagnosis of breast cancer, to evaluate treatment preferences in the setting of a hypothetical diagnosis of low-risk HR-positive breast cancer. A total of 40% stated they would elect to undergo SLNB, regarding the procedure as low-risk and providing prognostic information. Most women (73%) would choose to avoid radiation, due to perception of risk/benefit ratio and inconvenience. This study highlights the importance of effective communication regarding the excellent prognosis of these cancers in older women, and that de-escalation strategies are presented to reduce overtreatment and potential harms while achieving similar benefit.
Higher rates of genetic mutations (non-BRCA 1/2) have been observed in patients with breast cancer and another primary cancer compared to those with single primary breast cancer. Maxwell et al demonstrated rates of 7-9% compared to 4-5% for those with multiple primary breast cancer and single breast cancer, respectively. Further, they showed gene mutations (other than BRCA) are found in up to 25% of patients with breast cancer and another primary with their first breast cancer diagnosed ≤30 years old. Genetic testing is not a one-size fits all method and many patients are offered multigene panel testing. A multidisciplinary approach is key to identifying patients at higher risk, implementing effective screening and hopefully preventing future cancer development.
Erin Roesch, MD
The Cleveland Clinic
References:
Hardesty LA, Kreidler SM, Glueck DH. Digital breast tomosynthesis utilization in the United States: A survey of physician members of the society of breast imaging. J Am Coll Radiol 2016; 11S:R67-R73.
Bellio G, Marion R, Giudici F, Kus S, Tonutti M, Zanconati F, Bortul M. Interval breast cancer versus screen-detected cancer: comparison of clinicopathologic characteristics in a single-center analysis. Clin Breast Cancer . 2017;17:564-71.
Piccinin C, Panchal S, Watkins N, Kim, RH. An update on genetic risk assessment and prevention: the role of genetic testing panels in breast cancer. Expert Rev Anticancer Ther. 2019; 19:787-801.