How would you approach radiation for a patient with limited stage small cell lung cancer who refuses chemotherapy?

As the standard of care is systemic therapy for all that are medically fit, I’d spend time probing reasons, or the legitimate fears and concerns trying to change their mind. If limited disease, I would discuss the reasoning for local therapy, start with the standard (45 Gy/BID/3wks) and consider the optimistic 60 Gy/BID/ 4wks to only a PET avid target. My forecast would be systemic relapse. I’d try to get a “blood biopsy” for further evidence that local only is not such a great idea.