Would you treat an in-field recurrence/marginal recurrence of NSCLC following previous definitive chemoradiation with salvage SBRT?

I would layer the answer to the patient. First question: Local control, yes or no. If yes, then when... to answer that discussion of systemic option and timing in multiD eval. If yes, then how... surgery, IR thermal ablation, radiation. If radiation then dose/technique... 50 Gy 5 fx, 50 Gy 10 fx, 50 Gy 20 fx... and technique being proton or x-ray, then finally SBRT, IMRT, IMPT, 3D CRT...

Too often I hear people answer this question and they want to run to the last piece of either dose or technique... and then they back themselves into a corner on all kinds of EQD2 calcs and the like. Start high level and whittle down to the details... Also, frankly, skip the EQD2 thing. You are just making yourself feel good, which is, I guess, a nice thing...

This would depend entirely on the location of the recurrence and the overlapping dose from the prior plan with organs at risk, as well as the goals of care, patient performance status, and discussion of re irradiation risks. If directly in the mediastinum overlapping PBT/esophagus, there are significant risks, and it would not be unreasonable to select a non SBRT more fractionated approach or discuss with medical oncology the role of systemic therapy alone like immunotherapy instead of RT or in addition to lower dose RT. If recurrence were in the periphery of the lung away from sensitive mediastinal structures, then likely you would have less issues with an SBRT approach.

If I did decide to pursue RT, I would construct an eqd2 composite an...

Any updates on these responses? I have a patient who received prior IMRT to 60 Gy in 30 fractions with chemotherapy for IIIA NSCLC, and now he has recurrence in the primary site only. He is not a surgical candidate and I would like to consider re-irradiation to this 2.5 cm tumor with SBRT.