Rising rates of interval breast cancers have experts calling for more risk-based screenings
New interval cancer data have experts calling into question the use of age-based screening guidelines for women with a history of breast cancer.
Although annual screening mammograms are the most effective way to identify breast cancer in its earliest stages, not all cancers are identified during these exams. This is especially true for women who have a personal history of breast cancer.
Even when these women are adamant about attending their annual screenings, some will still develop interval cancers in between mammograms. Interval cancers (IntCa) are often more aggressive, making them more challenging to treat.
“Mammographic screening is the only proven method for early detection and mortality reduction of breast cancer,” Yuqi Zhang, PhD, with the Department of Medical Epidemiology and Biostatistics at Karolinska Institute in Sweden, and colleagues note. “However, many patients are missed at prior screening; thus, they receive their diagnosis between the interval of screening rounds, called interval cancer. Some IntCas are fast growing between screening rounds.”
A new analysis in JAMA Oncology suggests that IntCa rates among women with a prior history of breast cancer may be as high as 30%. As such, experts believe identifying women at greatest risk of IntCa is critical.
To determine whether certain risk factors increase the likelihood of IntCa diagnosis, researchers retrospectively analyzed the cases of over 500,000 women who underwent breast cancer screening between 1989 and 2020, paying close attention to those who were diagnosed with the disease more than once.
Nearly 30,000 of the women included in the analysis were diagnosed with breast cancer at some point, 10,631 (2.0%) of whom had screening-detected cancer, plus 4,369 (0.8%) who were diagnosed with IntCa. Around 30% of IntCas were identified in women diagnosed via screening.
Clinical factors found to be most associated with IntCa among the group were being older in age at first childbirth, use of hormone replacement therapy and having higher breast density. These women were more likely to have estrogen receptor–negative cancers, which was also found to be strongly linked to a family history of the same type of breast cancer.
The authors suggested their findings warrant reconsidering how women with a history of breast cancer are screened in the future.
“The results of this cohort study suggest that IntCa rates have not decreased with age-based screening, and implementing risk-based screening considering IntCa-specific risk factors is necessary for improving outcomes,” they concluded.
The study abstract is available here.
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.