SAITAMA (JAPAN) - Three elderly patients had to undergo additional surgery to remove surgical sponges left in their bodies during earlier medical procedures.

The separate incidents took place at Saitama Prefectural Cancer Centre in Japan.

In the latest case in November, a foreign object was discovered inside an 84-year-old woman a day after she had endoscopic surgery for lung cancer, according to Japan Today, citing a Fuji TV report.

Following an x-ray, it was found that the object was a surgical sponge measuring 5cm long and 3cm wide. It was lodged in the space between the patient's lung and ribs.

A surgery was immediately performed to remove the sponge, the cancer centre's officials said at a news conference on Wednesday (Nov 22).

There were two other similar incidents in February and July this year, reported Japan Today. The patients involved - a 79-year-old woman and an 81-year-old men - had also undergone endoscopic surgery.

Hospital officials did not say if the same surgeon was involved in all three cases.

None of the patients' lives were in danger, said the officials at the news conference. They apologised for the incidents and pledged that they would not happen again, reported Japan Today.