Skin case with PNI

[Haybrant]

Kind of a dumb question but didn't do a lot of skin in residency. I have a patient that underwent resection of a 3 cm left posterior shoulder squamous cell carcinoma (not immunosuppressed). Path said there was PNI of a nerve that was 0.31 cm in size. Mod differentiated, negative margins no LVI. Technically he has a reason for post op RT (size/PNI of a large nerve greater than nccn cutoff); if you would treat this what would you cover? Would you cover the dermatomal distribution up to the nerve root? What dose? He had a ct no concerning nodes. Thanks

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[OTN]

Size > 2 cm and PNI are both risk factors for local recurrence, so I would treat. I generally treat to 60 Gy in 2 Gy fx postop if the pt can travel, or 50 Gy in 20 fx if travel is an issue, though you will get much greater skin toxicity with the later regimen. I've never covered dermatomal distribution to the nerve root, but usually include a wide margin on initial disease with PNI- at least 2.5 cm. If all that's left is an incision, you'll need to put a wide margin on the incision (again, 2.5-3 cm), and check for postop changes on CT planning to make sure you're covering the area at risk. I would likely use en face electrons in this case, making sure to cover down to the shoulder musculature and adding bolus as needed to get Rx dose to the skin. Should be tolerated very well, and chances of success should be high.

 

[Neuronix]

Things that would reassure me not to go chasing anything (nodes or nerves) are: not a named nerve, no clinical symptoms of nerve involvement (e.g. numbness, neurologic pain prior to surgery). You can make an argument for regional nodal irradiation for PNI in the H&N, but here on the shoulder you're looking at treating a fairly low risk axilla with unclear benefit assuming they're clinically node negative.

Otherwise agreed with OTN.