ECC 2015

Time between melanoma excision and sentinel node biopsy does not affect survival

Charlotte Oude Ophuis - Erasmus MC Cancer Institute, Rotterdam, Netherlands

You’ve been conducting a retrospective survey, a retrospective study, of patients treated for melanoma with excision for melanoma. What were you trying to do in this and what was the issue about the interval between excision and the sentinel node biopsy that you were looking at?

As we all know, the sentinel node biopsy procedure is currently advised as a staging procedure as it gives us important information on the prognosis of patients. Currently most guidelines advise to perform the local re-excision and the sentinel node biopsy as soon as possible. The Dutch guideline even states that it should be performed within six weeks. There is little known on this topic but as it has clinical impact on high urgency referrals we decided to do an investigation in a large European cohort of nearly 4,000 people who had a sentinel node biopsy for melanoma.

So it could have clinical impact but what, in fact, did you find?

We found that for both patients with a positive sentinel node or a negative sentinel node the time interval which was taken until the sentinel node biopsy did not have any influence on the melanoma specific or disease free survival.

Why might that be? Is it because the excision is curative or what?

Mostly we think that the disease biology is written within the tumour itself. So the sentinel node biopsy is purely like some sort of landmark of which stage the disease is in, it doesn’t as much affect the disease itself. So it’s not a curative procedure, it’s purely informative.

It’s informative but informative of what?

Of a good or a worse prognosis. For instance, if you have a positive sentinel node then you know that the patients will have a worse outcome.

And then you can decide on therapy?

Exactly.

So what steps forward have you made by this study? You’ve established that the interval between sentinel node biopsy and the initial excision is irrelevant as far as the outcome for the patient?

Exactly, yes. That was our main aim, to look if this time interval did anything on survival and we’ve clearly proven that it doesn’t. So it can be used in clinical practice to reduce patient anxiety as people tend to want to be operated upon as soon as possible. We can now safely say that it doesn’t matter if you are operated on within two weeks or after nine weeks, for instance.

So it really affects the patient’s psychology more than the outlook? Yes, because the patient knows exactly what is happening. What should doctors take home from your findings, then?

That it’s important to perform the sentinel node biopsy as it gives us information on the stage of the disease but it should not be used to perform as soon as possible. So get your information but take your time.

But do you have the higher risk or a higher risk of a positive sentinel node if you wait longer?

Well we’ve studied that in a subgroup of this entire study cohort and we found that analysis there was a higher risk for patients operated on after six weeks but when we corrected for local centre protocols and all the known risk factors then we could not confirm this effect.

So in fact the overall message of your finding is quite reassuring?

Yes, exactly.

Thank you.