Calcutta: A cancerous bone in the right arm of a 13-year-old boy was removed so that doctors could use high doses of radiation to get rid of the tumour in it and fix it back in a cancer-free state in a nine-hour surgery in the city.

If treated in the conventional method of radiotherapy, doctors said, it would take several sessions and months for the treatment to be completed.

The boy from Tripura, Iman Hossain, had been experiencing pain in his arm since the middle of 2017. The teenager almost lost use of the arm after the tumour caused it to twist.

Nine months after the surgery, Iman is not only able to eat and write with his right arm again but has resumed playing badminton.

Doctors said the procedure, calledÿ extracorporeal radiotherapy, allowed them to put the bone through 50 "gray" (a unit of radiation dose) and free it of the tumour.

Had he been subjected to radiotherapy with the bone inside, Iman would have received 40 gray of radiation over 25 sittings, which would have been a long drawn process.

"The entire surgery took nine hours. The cancerous bone, 35cm long, was first removed from the body. It was taken to the radiation oncology department with all precautions. The bone was exposed to radiation before being brought back to the operating theatre and re-implanted," said Kaushik Nandy, ortho-oncologist at Narayana Superspeciality Hospital, who led the team of doctors who performed the procedure.

Tests after the surgery showed no cancerous cells but the child is still undergoing chemotherapy, which will end shortly. The boy will be off medicines after the chem-otherapy but there will be chances of a relapse, doctors said. Oncologists said this technique of treating certain bone cancers, in vogue in developed countries for four to five years, led to faster cure and less suffering for the patients.

"The challenge is to be able to ensure that blood supply to the bone is restored and it does not become dead," said surgical oncologist Arnab Gupta.

Jiban Krishna Bhattacharya, 53, from Palta in Barrackpore, underwent a similar operation during which three-fourths of his hip bone was taken out, treated with radiation and put back in January. Bhattacharya walks with a walker and his physiotherapist has assured him that he will gradually regain the strength to move around without support.

The procedure costs Bhattacharya Rs 4.5 lakh. A doctor said the expense would have touched Rs 30 lakh had Bhattacharya opted for an artificial implant. "An artificial implant would have lasted at the most five years, whereas his own bone would last for life," the doctor said.

The type of cancer Bhattacharya was afflicted with does not respond to or require chemotherapy.