Einstein Hospital incorrectly told a woman her mammogram results were normal. A year later, she was diagnosed with cancer.

“We are pleased to report,” the letter from Jefferson Einstein Philadelphia Hospital read, “that the result of your recent mammogram shows no sign of breast cancer.”

But the letter was wrong. Her scan had actually been inconclusive, and an internal error resulted in the patient not being notified to come back for additional testing.

The issue came to light one year later, when the patient returned for another routine mammogram and was diagnosed with breast cancer.

The incident, described in a report released by Pennsylvania hospital inspectors in September, drew one of the state’s harshest warnings for the North Philadelphia hospital formerly known as Einstein Medical Center.

Einstein staff realized that the patient’s scan a year earlier had been misclassified, which resulted in her receiving an incorrect notification letter, Damien Woods, a spokesperson for Jefferson, said in a statement. The hospital referred the woman for follow-up care and reported the incident to the health department.

During the health department’s investigation, inspectors found that the hospital’s board of trustees had not done enough to prevent the mistake from happening again. The board had not investigated the incident or done quality control audits to ensure patient notification letters were accurate.

In a lawsuit filed in Philadelphia in June, another Einstein patient claims doctors also never informed her that her mammogram results were inconclusive, and says she was never asked to come back for more testing. Earlier this year she was diagnosed with breast cancer. The woman’s case falls within the window of time in which health inspectors say the hospital was not conducting quality control audits.

To fix the safety problems inspectors found, Einstein updated its protocol for reading mammograms to reduce the likelihood of another patient notification error.

The electronic system now prevents radiologists from closing out their notes about a patient’s scan if they have not completed the entry. The hospital has also agreed to increased monitoring, to check daily that letters correlate with scans.

“Jefferson Health is committed to providing our community with the highest quality of care,” Woods said. He said the hospital cannot comment on the pending lawsuit.

The Inquirer was unable to reach the woman who is suing or her lawyer.

» READ MORE: Penn’s BRCA cancer vaccine trial aims to prevent the disease in healthy people

Mammogram reporting mistakes are rare but alarming, medical experts said.

Breast screening is considered medicine’s best tool for catching breast cancer in early stages, when it is most treatable. Routine screening is recommended for women with average risk of breast cancer beginning at age 40 by the United States Preventive Services Task Force, a panel of independent experts whose guidance sets national standards.

“We want to be treating cancer because we did the screening and found it, not because someone starts experiencing symptoms,” said Oluwadamilola “Lola” Fayanju, the breast surgery division chief at Penn Medicine, who is not involved in the Einstein cases.

Radiologists follow a detailed process to read and categorize screening mammograms, which are the routine scans for people of average risk.

Mammograms are evaluated using a rating scale called Breast Imaging Reporting and Data System, or BI-RADS. The rating system assigns each scan a number between zero and six.

A zero rating means the scan was inconclusive, and the patient should come back for additional scans.

A rating of one means the scan did not show any signs of cancer; a two means the scan showed an abnormality that doctors believe is benign and not likely to cause cancer. Higher numbers indicate a greater likelihood of cancer and more urgent need for additional testing.

Each BI-RADS score correlates with a letter instructing patients on any additional steps they should take.

Health inspectors found that a patient’s mammogram should have been rated “BI-RAD 0,” and she should have received a letter asking her to return for additional scans.

The lawsuit from a different patient also alleges that her scan was rated inconclusive, BI-RAD 0, and that doctors didn’t ask her to come for more imaging.

Exact protocol can vary by health system, but doctors typically read screening mammograms in batches and send results to patients within a few days, said Claire Streibert, site chief of breast imaging at Fox Chase Cancer Center, who is not involved in the Einstein cases.

Federal law requires notification to patients within 30 days.

Typically notification letters are automatically produced and sent based on the BI-RADS score entered into the patient’s electronic health record, Streibert said, and providers are required by federal law to follow up with phone calls if patients do not respond to notification letters requesting additional testing.

Jefferson said it plans to prevent future errors with a new “hard stop” in its electronic record system that requires a radiologist to enter a BI-RADS classification before they are able to close out their notes about a patient’s scan.