Approximately 30% of breast cancers are not detected at screening, but rather between two screening examinations, and are known as interval breast cancers.
Interval, breast cancers are likely to be diagnosed at later stages and are more likely to present with metastases in local lymph nodes, thanpatients with a diagnosis of mammographic screening detected cancers.
Interval breast cancers are more likely to be estrogen receptor negative, progesterone receptor negative, and triple negative as compared with screen detected breast cancers.
Interval, breast cancers are associated with a worse prognosis.
Patients with interval breast cancers, have a higher likelihood of having first-degree relatives with breast
Patients with interval breast cancers are also more likely than those with screened detected breast cancer to develop other tumors come indicating a genetic cause.
Higher mammographic density reduces screening sensitivities and increases the likelihood of subsequent interval breast cancer.
The germline protein truncating breast cancer variants in five genes – ATM, BRCA1, BRCA2, CHEK2, and PALB2 all are strongly associated with the risk of breast cancer, and are found to be more common in patients with interval, breast cancers.