For a young patient with advanced TNBC with a single lung nodule status post NAC, not amenable to biopsy, would you consider SBRT to the lesion?

Look for prior imaging (they’re young so may not have prior chest imaging with any significant lead time to draw any conclusions). In the absence of any evidence of other sites of disease and no history of evolution of that nodule, I’d move forward with the completion of appropriate adjuvant therapy...

I would probably continue adjuvant chest wall/nodal radiation and would treat the lung nodule with SBRT. The patient is likely in trouble if she progressed during NAC, but local recurrences can be very morbid and the radiation is not associated with really bad toxicity. Regarding the lung metastasis...