A public hospital in Chiba Prefecture said Friday it removed the right breast of a female patient in her 30s by mistake based on data belonging to a patient with more aggressive breast cancer.
The prefecture-run Chiba Cancer Center in Chiba city said the woman's cancer was in its early stage and it did not have to remove the entire right breast immediately. It offered apologies to her.
Hospital staff conducted a biopsy on the woman in mid-October, and her data got mixed up with that of a female patient in her 50s at the hospital, it said. The latter woman had undergone an examination the same day and was later diagnosed with aggressive breast cancer.
Early this month, the hospital removed the right breast of the woman in her 30s. But when her tissue was examined on Dec. 15, it realized the mistake had occurred, according to the hospital.
"We wish to offer our deep apologies to the patient and her family for causing such an accident," hospital head Matsuo Nagata said at a news conference.