Sentinel lymph node for melanoma ($LN)

My letter in the BMJ is here. Sadly they sanitised my rapid response (here) which ended saying:

Finally, the simplest explanation for the persistence of SLN — in the absence of convincing RCT support— is surely that given by people such as John Wennberg in explaining variation in health care provision: money — or at least practice styles that encourage consumption at the margin of rationality [4]. It is known as $LN for a reason.

J. Meirion Thomas deserves credit for challenging this dogma about $LN biopsy