Is there a general consensus on margins to use when treating SCCIS or BCC with ED&C?

ED and C is a procedure that is done largely by 'feel'. Tumor is generally softer and more friable than normal skin, and is therefore more susceptible to removal with moderate pressure from a semi-sharpened curette. Generally speaking, I don't obsess over margins when ED and C'ing a low-risk skin cancer. I focus on removing all tissue that is not readily adherent and cauterizing a narrow perimeter around the curetted defect. Facility with a curette is key, and learned with experience. Generally speaking, I semi-aggressively curette any NMSC that I plan to excise. Helps with establishing the extent of the tumor and planning for excision margins. Examination of the excised specimen is also a reasonable quality control measure. If 90% of those...

The literature says that vigorous curettage has a very high cure rate, >95%. I will only curette if the basal cell carcinoma (BCC) is superficial or clearly nodular, with telangiectasia and friability. I use various-sized curettes depending on whether there are focal areas that appear deeper. I make sure I go to the reticular dermis, which leaves a white surface after curetting. A small margin of surrounding epidermis is taken as well. Please note the emphasis on vigorous curettage to the white reticular dermis. Squamous cell carcinoma in situ (SCCis) is treated similarly, with great cosmetic and curative results.

I’m not sure there is a generally recommended specific margin to remove with ED/C of BCC or SCC. But some margin should be taken. It makes sense to take about the same margin that you would if you were going to excise the lesion, since the objective is the same - to clear the lesion. So, for a relatively small, nonaggressive BCC in a non-high-risk area, around 2 mm should suffice. For very small lesions, slightly less; for larger ones, slightly more. Instead of just ED/C, I almost always perform shave + ED/C after carefully assessing and marking the lesion’s border. This way, I know that I’ve taken the specific margin, plus it’s a much “cleaner” procedure, as there is typically very little to curette out if I’ve gauged the depth well.