Europe's hospitals and doctors work together to help young patients leave Ukraine.

Since the beginning of the Russian invasion, millions of people have fled Ukraine. Many are suffering from the traumas of war and serious health conditions like cancer.

Europe's hospitals and doctors work together to help young patients leave Ukraine.

Many young patients made the risky trip from war-torn countries to Poland where they are now fighting another battle. Overnight, two critical pediatric patients were transported by volunteers from Lviv to Warsaw. Kirill, a 13-year-old boy, was one of those children. He was brought to the operating room within hours. It was his 36th operation.

CBS News interviewed Dr. Radek Chaber from the Medical University of Rzeszow about the treatment of patients from Ukraine with serious conditions such as cancer and other hematological disorders. He said that they are located just an hour away from the Ukrainian border.

Doctors say that patients who are seriously ill should not have their treatment interrupted in order to have the best chance of recovery. However, in a war zone nothing is certain. St. Jude's Children's Research Hospital, a U.S.-based hospital, partnered with European hospitals and doctors to help the most vulnerable.

Up to now, there are 28 countries and more that 201 clinics around the globe offering support for young people.

Yarsalava, a patient with acute leukemia was brought from Ukraine. She was traveling to Ireland when she was struck by a severe infection. Her mother stated that Yaraslava received the necessary treatment in Poland and her family, which includes her two young siblings have been allowed to stay in her hospital room until she is ready to move.

"These children from Ukraine might not be treated, or cured without treatment outside Ukraine. Chaber said that most of them would die.

"So, you are saying that for these patients with cancer to survive, they need to be treated in Ukraine? Or they might not survive?" Ruffini asked.

"Yes. We must do everything. Chaber replied that every patient from Ukraine should now be, possibility, to receive treatment somewhere else."

These doctors report that around 400 children were evacuated from Ukraine in the first days of the conflict, and another 150 are expected to arrive by the end of this week.