When does perineural invasion for a squamous cell carcinoma of the skin of the head and neck merit adjuvant radiotherapy?
Following Mohs surgery and in the absence of other high risk features, do you offer RT for any PNI? A single nerve < 0.1 mm? A single nerve > 0.1 mm? "Multifocal PNI"? Named nerve? Or do you use combinatorial requirements?
Answer from: Radiation Oncologist at Academic Institution
In cutaneous squamous cell carcinoma, the presence (vs absence) of perineural invasion is associated with a higher likelihood of local tumor recurrence after a margin negative excision.
However, several recent studies have shown that for small caliber perineural invasion (invasion of a nerve &...
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Answer from: Radiation Oncologist at Academic Institution
I think @Christopher A. Barker's answer is perfect. The problem is that Mohs surgeons don't measure the caliber of the nerve diameter; despite the literature on this subject, the reports in my experience remain highly subjective. However I wouldn't radiate a small (presumably <0.1 mm) single focu...
Answer from: Radiation Oncologist at Community Practice
Here is a retrospective review that defines extensive versus focal involvement in regards to PNI and helps define the risk of failure + or - RT.
http://www.sciencedirect.com/science/article/pii/S0167814016311677