A Swedish woman undergoing treatment for cancer said she was shocked to receive a letter from the Swedish Social Insurance Agency declaring her dead.

The Boden, Sweden, woman said she received the letter just as she was beginning treatments for cancer and the insurance agency has since apologized for the mix-up, Swedish news agency Tidningarnas Telegrambyra reported Tuesday.

"Unfortunately this is a case of human error. The administrator was dealing with several cases simultaneously and a mix-up occurred with the address details," said Eva Sjoberg, a representative from the agency's Malmo office. "We apologize profusely for this. It has never happened before and I hope that it will never happen again."

Officials told TT the agency has altered its operating procedures as a result of the incident. Workers are now allowed to have only one opened case file on their desk at a time to avoid further mix-ups.