Is a close but negative for margin (<5 mm) an indication for adjuvant radiation in oral cavity squamous cell carcinoma?

I treat a close margin in the high-risk post-op PTV (66Gy) but I do not ask med onc to add chemotherapy unless the margin is a true positive.

Hi, I treat close and positive but reexcised negative as positive. The likelihood of salvage is low so go whole hog.

It depends on other factors. In the era of a greater understanding of the biology of SCCHN & given the long-term consequences of therapy, we need to critically assess the role of adjuvant therapies such as these. So what are the factors that would play into my recommendation of adjuvant RT in this setting? They are tumor size, depth of invasion, presence of perineural invasion (PNI), etc. Said more explicitly, a patient with a very small, well-differentiated primary without Perineural invasion and minimal invasion, it becomes difficult to routinely recommend adjuvant RT to the oral cavity.

Like most things in modern medicine, the answers are no longer absolutes but rather more nuanced but rooted in the evolving evidence.