PROVIDENCE, R.I. (WPRI) — Cancer patients undergoing radiation treatment at four local health care centers had to have their appointments moved due to a software outage caused by a cyberattack on an outside vendor.

The outage affected at least 50 patients at Southcoast Health’s cancer centers in Fall River and Fairhaven and an unknown number of patients at Rhode Island Hospital and the Lifespan Cancer Institute in East Greenwich.

Elekta, which hosts the hospital networks’ radiation oncology cloud service, said it was the victim of a malware/ransomware attack on Tuesday. The company said it “immediately took action to contain the attack,” while Lifespan and Southcoast rescheduled appointments on Tuesday and Wednesday as a precaution.

In a statement Wednesday afternoon, Elekta said the threat had been fully contained and they anticipated its systems would be fully operational by Thursday.

As of 2:30 p.m. Wednesday, Southcoast said its systems were back online and they were running tests to make sure everything was working properly.

Thursday morning, Lifespan said they had resumed use of the Elekta cloud infrastructure and resumed treating patients at both affected locations.

Both Elekta and the two hospital groups said there’s no indication that any patient data was compromised.

“This appears to have been a ransomware attack intended to encrypt the data stored on this system,” Elekta wrote in the statement. “There is no evidence that any data were extracted or copied and we do not believe that the hackers have any of the stored data in their possession.”

Lifespan said appointments for Tuesday were moved to Saturday, April 10, while Wednesday’s appointments were rescheduled for Sunday, April 11.

Southcoast also noted that had the outage lasted more than a few days, it has contingency plans in place to make sure patient care wouldn’t be totally interrupted.