A hard drive containing the medical records of 781 cancer patients has been stolen from a researcher at Amsterdam’s Antoni van Leeuwenhoek hospital.

The drive, which was not secured with a password, was taken from the boot of a hospital worker’s car in December. The specialist cancer hospital made the theft public on Thursday.

The drive contains information about patients who are or were taking part in academic research and lists their names, dates of birth, the types of tumors they have and details of any experimental treatment they are undergoing. Of patients, 199 are still alive, and have all been informed about the theft.

The hospital said its staff are not allowed to take away patient information which has not been secured and that it had only recently been informed about the theft. The contract with the researcher concerned will not be extended, the hospital said.

The theft of the information will not have an impact on patient treatment or ongoing research, the hospital said.