A small girl in a pink sweater waved goodbye through the smudged window of a bus as it prepared to depart Gaza on Saturday, packed with 37 ill and injured patients, most of them children with cancer, in need of medical treatment that Gaza’s war-ravaged hospitals cannot provide.

It was the first time in nine months that medical evacuees have been able to leave Gaza by the Rafah border crossing, and outside Nasser Hospital in Khan Younis, weary mothers held their sick and listless children…