Undergoing surgery for breast cancer will always be a life changing experience, both physically and emotionally. However, a new technique being trialled in Auckland has the potential to reduce the long term physical side effects, such as swelling of the arm or chronic pain, which sometimes follow surgery for breast cancer.



Photgraph L to R: Ms Lea Devereux, the first recruit into the sentinel node biopsy trial, Mr Richard Harman, breast surgeon, North Shore Hospital, Ms Lorraine Neave research nurse and trial coordinator.

The procedure, known as Sentinel Node Biopsy (SNB), is currently being investigated in an Australasian trial, and surgeon Mr Richard Harman of Waitemata Health is running the New Zealand arm of the study.

Says Mr Harman, "It is always harder to obtain funds for surgical research as opposed to drug trials and we were in danger of not being able to complete our part of this important trial. However, a recent grant from the Genesis Oncology Trust means that North Shore Hospital can employ a part time research nurse to co-ordinate this hospital's input and we can now continue to recruit patients and feed data into the trial centre in Sydney."

So what is Sentinel Node Biopsy and why might it be better for the patient?

"When an invasive breast tumour is removed, most of the lymph nodes under the arm on the same side of the body are usually cut out as well," explains Mr Harman.

"Removal of these axillary nodes is termed Axillary Clearance. We do this because when cancer cells escape from the primary tumour, they travel through the lymph system and are collected by these axillary nodes. The cancer can start to grow in the lymph nodes and eventually escape to cause new tumours in organs such as the liver, brain lung etc. It is these secondary cancers that can kill a patient so it is important that the affected nodes are removed."

Lumpectomy or mastectomy, coupled with axillary clearance, is the accepted "gold standard" surgical treatment for breast cancer and surgeons have prolonged many lives with this procedure. However, it is not without complications and long term side effects.

"The lymphatic system is a drainage network that removes fluid from tissue - fluid that has seeped through small blood vessel walls to nourish the tissue. If the drainage system is damaged, i.e. by surgery, then fluid can build up. This 'lymphoedema' in the arm is the cause of mild to severe disability in up to 50% of women and men who undergo axillary clearance.

"Fluid in each area of breast tissue drains into one or two axillary nodes and any cancer cells from a tumour in that part of the breast will localise in these nodes - the "sentinel" nodes."

Mr Harman says it occurred to surgeons 20 years ago that if the sentinel nodes could be identified and checked for cancer, the need for axillary clearance could be greatly reduced, and consequently reduce the incidence of lymphoedema and other complications.

"The tricky bit is identifying these nodes," he says. "Building on work carried out in melanoma patients, researchers in Santa Monica, California developed a combination of radioactive tracer and dye techniques which allow an experienced surgeon to pinpoint the sentinel nodes with 97% accuracy."

The key to successful sentinel node biopsy is the skill of the surgeon.

A few hours before surgery, a low level radioactive tracer is injected into the breast in the area of the tumour. Then, just before the operation, a blue dye is injected in the same area.

Both these tracers accumulate in the sentinel node. After the surgeon has excised the tumour, the area around the armpit and shoulder is scanned with a small hand held radiation detector probe.

"The detector "pings" when it is over the sentinel node or nodes and the surgeon makes a small incision to remove these. The accumulation of blue dye provides visual confirmation that the node(s) removed are likely to be sentinel. A pathologist then examines the node under the microscope to determine if there are cancer cells present.

"If there are none, no further nodes are removed. If cancer cells are present in the sentinel node then this indicates that the cancer cells have escaped from the breast and a full axillary clearance is performed."

Mr Harman says it takes a lot of practice with the radiation detector to be able to accurately identify the sentinel nodes.

"The American College of Surgeons recommends that physicians perform at least 30 sentinel node biopsies followed by complete axillary clearance before they consider using sentinel node biopsy on its own," he says.

"During this probationary period the nodes that the surgeon identifies as sentinel, as well as all the other axillary nodes, are checked by the pathologist for the presence or absence of cancer cells. Once surgeons have reached an 85% success rate in identifying sentinel nodes they are deemed proficient in the technique. All the surgeons involved in our trial have reached or surpassed this level of proficiency."

Mr Harman says the trial is extremely important.

"If you have a proven and very effective surgical procedure in place, you have to be very sure that any new technique is better, and this requires research. Because axillary clearance has been such a successful part of surgery for breast cancer, it has taken over ten years of research and follow up to establish the potential of sentinel node biopsy as an alternative to axillary clearance, and our trial is part of the final stage of this accreditation process."

All women who take part in the trial will undergo the sentinel node biopsy procedure. However, half of them will have a full axillary clearance immediately after. Those in the sentinel node biopsy only group, whose nodes are clear, will have no further treatment. If cancer cells are found in the nodes of those who have only had sentinel node biopsy, axillary clearance is carried out to remove the rest of the axillary nodes. "Therefore", says Mr Harman, "we will have two groups of women with the same range of diagnoses and breast surgery, some of whom have had sentinel node biopsy alone and some of whom have had full axillary clearance.

"We will be evaluating these patients regularly over the first 12 months and then at yearly intervals over the next five years. Our primary interest will be in the incidence of the side effects that can sometimes follow full axillary clearance - swelling of the arm, arm function, pain, infection, damage to nerves etc. Evidence to date suggests that these adverse events are very much reduced in patients who undergo sentinel node biopsy alone. " Survival and disease status will continue to be monitored for life. In New Zealand the number of women undergoing surgery for breast cancer is increasing as a result of early detection from screening. Therefore, any technique that limits the long term negative effects of treatment of breast cancer will be a major advance.

Currently 650 patients have consented to participate in the SNAC trial throughout Australasia. North Shore Hospital has the 4th highest accrual in Australasia with 49 women agreeing to participate since 2001.

Lea Devereux, the first patient to enter the North Shore trial, had sentinel node biopsy performed in January 2002, at the age of 37. A therapist specialising in Jiin Shin Jyutsu, she says her recovery time was less than one week.

"I had only one night in the hospital, took it easy at home for a few days and was back at full time work within two weeks," says Lea.

When Lea discovered she had breast cancer, she says she wanted a plan of action. She met with Richard Harman the week she was diagnosed and was informed about the trial.

"I feel lucky that I was able to take part. At no stage do I feel I have put myself in any danger by opting to be part of the trial. Rather I feel very protected and extremely well informed."

Lea has continued to have regular follow-up visits and is extremely pleased with her progress.

Says Mr Harman, "we are grateful to the Genesis Oncology Trust for helping us to bring sentinel node biopsy one step closer to mainstream treatment of breast cancer."