Hoang Son Pham before his tracheostomy in January. (CBC)

A Vietnamese orphan in Halifax with a benign, disfiguring facial tumour is preparing for a surgery this week at Children's Hospital Boston to reduce the size of the growth.

Son Pham, 11, will have lip reduction surgery on Thursday. Doctors will target a football-sized tumour that has built up in front of his lips so it protrudes less, said Olwyn Walter, who's been caring for the boy over the past year in Halifax.

"He knows that this is the first time that he'll see a significant difference," Walter said in an interview with CBC News: Morning on Tuesday.

"He's used to coming back from Boston actually looking worse than he went because the schlerotherapy treatments cause extensive swelling. In this case, he is going to come back looking different, and hopefully somewhat better, given that the removal of his malformation will have begun."

Son has traveled to the U.S. seven times since January to prepare for the surgery. Doctors have given a series of injections, called sclerotherapy, to reduce the blood and build up of tissue in the affected area.

In January, Son had a tracheostomy, in which an incision is made in the trachea and a tube is inserted to keep the airway open throughout his treatment.

More surgeries ahead

Surgeons will not yet touch the largest part of the growth in Son's cheek area. They plan to do so, but it's not yet known when, Walter said.

Toronto's Hospital for Sick Children spent months reviewing Son Pham's case, but said in October it wouldn't proceed because there were risks to the procedure and the growth was not considered life threatening.

The U.S. team disagreed, deeming his condition life-threatening because they feared the growth could block the boy's windpipe and prevent him from eating properly.

Son faced risks of massive swelling and bleeding, but the sclerotherapy and tracheotomy have mitigated the risks to those of minor surgery, Walter said.

Son arrived in Canada in 2007 after an official with the Children's Bridge Foundation, an Ottawa-based charity, found him at a Vietnamese orphanage.

Walter, vice-president of the foundation, brought Son and his nanny to Halifax, where she lives with her two daughters and husband. The boy is going to school and studying English as a second language while he stays in Canada.

About $300,000 has so far been raised to help Son. Air Canada Kids' Horizons is providing the flights to Boston, and many of the specialists involved in Son Pham's treatment will also be donating their services.

Son will face several more procedures before the growth is manageable and his lips are reconstructed. He could return to a foster family in Vietnam in 2009, Walter said.

With files from Canadian Press