Sonia was found hanging from a tree near the hospital's staff canteen at around 9 am, police said. Guru Teg Bahadur hospital authorities have claimed that she was not their patient.
The victim, a resident of Himachal Pradesh, was identified from the medical documents recovered from her.
"Document recovered from her possession revealed that she had been undergoing treatment for cancer for the last several years. There were treatment slips of hospitals of Solan district of Himachal Pradesh and Varanasi in Uttar Pradesh," a police official said.
A team of GTB Enclave police station is investigating the matter and trying to ascertain her family details so that they can be informed, police said.