For a pathologic Stage I squamous cell carcinoma of the oral tongue with negative margins and adequate neck dissection, is perineural or lymphovascuar invasion alone an indication for adjuvant radiotherapy?

I think Dr Eisbruch is spot on- patients with PNI do worse in the surgical literature, but the benefit of XRT in this scenario to obviate recurrence is far from robust. My personal belief is that PNI is not a sign of neurotropism like in melanoma or adenoid cystic ca, but likely another surrogate for margin, with PNI suggesting inadequate margin (recognizing that margins are only interpreted on selected slices, as the entire specimen is not truly looked at microscpically). Based on a sense that ...

PNI or lymphvascular invasion in oral cavity cancer, in the absence of any other risk factor, are indications for post-op RT according to NCCN recommendations (even for small T stages). There is more data about PNI compared with LVI as a factor that increases substantially the risk of local failure. This added risk is between 20-40% depending on the series. There is much less literature about the impact of lymphvascular invasion; it probably increases risk of LN metastases in the way that this r...

I add postop RT for PNI but not for LVI as a sole indication.