Would you ever consider repeating chemoradiation for patients with locally recurrent small cell lung cancer after prior chemoradiation for LS-SCLC?  

As with any good question, the answer is, it depends. Several factors would impact this decision - specifically the time frame - has it been a very short interval or long? I would at least ask the question if the relapse is SOLELY local-regional (i.e., no evidence of recurrence outside of the chest ...

I have re-treated in-field local recurrence SCLC advising thoracic radiotherapy first using SBRT dose and technique. Also, new lung cancers are more common in those who could not stop smoking.

An unfortunate situation but unfortunately, most patients do relapse even after definitive therapy. I think there is a "could you" aspect and a "should you" aspect. Can you repeat chemoradiation? This is more of a safety question and it largely depends on the location, the underlying lung function, ...

This is a rare clinical scenario, but if confirmed recurrence pathologically and no distant metastatic disease, repeat chemoRT can be considered.  The main issue boils down to feasibility - I agree with discussing with your local Rad Onc regarding this. SCLC frequently has more central diseas...