After having both breasts removed, the patient can opt to leave her chest flat or undergo further surgery to rebuild the breasts.
A mastectomy without breast reconstruction carries a minimal risk (1 to 2 per cent) of wound infection, if the patient has other risk factors such as diabetes or obesity.
Adding breast reconstruction raises the risk of complications to 2 to 10 per cent.
The risk of a double mastectomy with breast reconstruction is more than twice that of the process on a single breast - 5 to 25 per cent - as the operation requires a longer time.
Breast reconstruction is done by a team that includes a breast surgeon and a plastic surgeon, said Dr Esther Chuwa, a breast surgeon at Gleneagles Hospital.
Such surgery can be done using either breast implants or tissue taken from elsewhere in a woman's body, she said.
It can either be done immediately, during the same operation as the mastectomy, or in a separate operation later.
With immediate reconstruction, the surgeon rebuilds the breasts during the same operation as the mastectomy, and uses a technique called skin sparing or nipple sparing mastectomy, said Dr Chuwa.
In each breast, all of the skin including the nipple is preserved, but the underlying breast tissue and the ducts behind the nipple are removed.
This operation carries a 5 to 20 per cent risk of nipple necrosis (tissue death) due to poor blood supply to the nipple as it is left with only its surrounding skin as its source of blood, Dr Chuwa said.
The insertion of the implant in a breast is usually done in two stages.
The surgeon inserts a device called a tissue expander underneath the skin and chest muscle that remain after a mastectomy.
The device is gradually filled with fluid during the patient's subsequent visits to the doctor's clinic after surgery.
After the chest tissue has been stretched sufficiently to create space for the implant - usually about three months after a mastectomy - the device is replaced with an implant.
If the patient chooses to have breast reconstruction using her own tissue, the tissue is taken from elsewhere in her body, most commonly from her abdomen, and used in place of the implant.
Women can choose their type of breast reconstruction method based on what is important to them, Dr Chuwa said.
Reconstruction surgery using tissue is technically more challenging than that using implants, and can take up to eight to 10 hours, more than twice the time needed for implant-based reconstruction, she said.
During surgery, patients tend to lose more blood and could develop complications, such as excessive bleeding and blood clots forming due to the longer surgery, which could block the lung arteries and cause the lungs to fail.
In the longer term, patients may have pain, weakness and scarring in the area where the tissue was taken from, and the transferred tissue could die.
But such serious complications occur in less than 3 per cent of patients in experienced hands, said Dr Chuwa.
Patients who have had tissue-based breast reconstruction also require longer hospitalisation and recovery periods.
However, reconstruction using tissue results in breasts that look more natural, and patients are less likely to need repeat procedures than if they had implants inserted, Dr Chuwa said.
About one in three women with implant-based reconstruction will need some form of revision in the 10 years after the initial surgery, she said.
For instance, the implant has to be removed if the area becomes infected.
The implant could break through the skin or rupture, leading to the silicone leaking into the surrounding tissue and lymph nodes (small, oval glands that trap bacteria and viruses).
This results in pain and formation of hard scar tissue around the implant.
The longer a woman has implants, the more likely she is to have complications and to need to have her implants removed or replaced, Dr Chuwa said.
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