While many breast tumors are detected through routine mammograms, which use X-rays, tumors can develop in between yearly mammograms. These tumors, known as interval cancers, account for 20% to 30% of all breast cancer cases, and they tend to be more aggressive than those found during routine scans.

Detecting these tumors early is critical: When breast cancer is diagnosed in the earliest stages, the survival rate is nearly 100%. However, for tumors detected in later stages, that rate drops to around 25%.