AMAROS trial: radiotherapy versus lymph node dissection in breast cancer

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Published: 2 Jun 2013
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Dr Robert Mansel - Cardiff University, UK

Dr Robert Mansel talks to ecancer at ASCO 2013 about the AMAROS trial which investigated complete axillary lymph node dissection with axillary radiation therapy in treating women with invasive breast cancer.

ASCO 2013

AMAROS trial: radiotherapy versus lymph node dissection in breast cancer

Dr Robert Mansel - Cardiff University, UK

We presented the AMAROS trial which is the comparison between radiotherapy to the axilla and surgery in a patient who has a positive sentinel node. This is a long-awaited trial, a large trial and previously we had only very small studies so we didn’t know the answer whether radiotherapy actually could work for the positive sentinel node. So this trial demonstrated very clearly that in terms of controlling the disease in the axilla in breast cancer that radiotherapy was just as good as surgery. So it has big implications because it means patients don’t need to go on and have more surgery when they have a positive sentinel node.

There are 4,800 patients involved and they were randomised when they had a positive sentinel node, so it’s a sub-group of the 4,800, and they were then randomised to either radiotherapy, which was very carefully controlled, or surgery in European centres. We found that the control of the disease in the axilla was equivalent, in other words radiotherapy was just as good as surgery. Because at the moment the standard of care is more surgery so this means that radiotherapy can be used instead of surgery, you don’t have to go back.

The other very important finding was the side effects issues because surgery actually showed more lymphoedema, more arm swelling, and this clearly is of major concern to patients. So surgery at one, three and five years had more arm swelling than radiotherapy did. The only thing that was increased on radiotherapy is a bit more stiffness of movement in the arm but that disappeared by five years and there was no difference between surgery and radiotherapy at the five year mark.

What do you think the clinical implications should be?

I think they’re very big and also economically very big because it means basically that patients don’t need to go back to the operating room for more surgery so that will save surgery time. At the same time patients will get less morbidity and less side effects so again that’s a big saving for the health system. In fact, lymphoedema was half as common on axillary radiotherapy compared to surgery and lymphoedema is expensive to treat because it is a lifetime condition.

Is this being implemented in other countries?

It is as a result of the Z11, the US trial which had actually surgery versus nothing, or they think nothing, in the axilla but those patients, as were the AMAROS patients, also had a lot of systemic therapy so that’s having some effect on the axillary disease. But there are a number of issues around Z11 in the sense that it was very underpowered and the radiotherapy schedules were not all that well controlled. So there’s a concern that in fact in Z11 the good effect of doing nothing more might well have been a by-product actually of the radiotherapy. In other words you might argue that Z11 maybe was just a pilot to AMAROS but in AMAROS we do know where the radiotherapy is given and what the doses were. The problem in Z11 is the radiation protocols were left up to the institution, they weren’t set by the trial.

What are the cost implications and will this save money?

Yes you can because you’ll certainly save it on operating room time and surgical bed occupancy. If you use radiotherapy instead of surgery there will be an increase in radiotherapy but this group of patients is having radiotherapy anyway so it’s just a difference in the planning system. You don’t actually have to subject people to radiotherapy who weren’t going to get it because both trials, Z11 and AMAROS, are mainly patients having breast conservation who are going to have radiotherapy to the breast anyway.