How do you approach a patient with NSCLC and 3 oligometastatic lesions that are 4-5 cm in muscles of the extremities?

This is a great question which I suspect will lead to a wide range of answers. My thought is that if the indication is strong enough (which could be iffy as these are likely poor prognosis metastatic sites) that I would proceed with SBRT in this setting - the strongest factors in my decision of SBRT versus palliation/observation would be the natural history of disease to date, and the perceived risk of aggressive treatment of the lesions based on their location (and secondarily size).

Muscular/soft tissue metastasis are rare, so it is not clear that one can extrapolate at all from available data, though ideally, the case would fit the selection criteria of either the Iyengar et al., PMID 28973074 and Gomez et al., PMID 31067138 trials, or S...

I will not chime in on the medical rationale for locally aggressive therapy in an oligometastatic lesion in soft tissue/muscle, as this indeed could be an indicator of disease aggressiveness and it's hard to know if there will be a long-term benefit. Certainly, it's plausible.

However, if one has already decided to treat a muscle lesion with SBRT, one could extrapolate dose from our experience (N>120) of hypofractionated preoperative radiation for soft tissue sarcoma of the extremity/trunk, published in 2020 and most recently updated at ASTRO 2021. A dose of 30 Gy in 5 fractions is safe and effective even in the preoperative setting, even for very large tumors >10cm. The group led by Dr. @Dr. First Last at MCW has used 35 Gy in 5 fractions ...

I am skeptical this will be a good idea for the patient to offer SBRT given this presentation is atypical and not representative of an oligomet scenario that would more typically benefit from SBRT, but rather indicative of unusually aggressive disease with poor near term prognosis. My inclination would be to first speak with medical oncology if the patient is out of options.

Imaging perspective muscle mets: (https://www.sciencedirect.com/topics/medicine-and-dentistry/muscle-metastasis.

“Different types of CT findings have been recognized, including focal intramuscular masses with homogeneous contrast enhancement, abscess-like intramuscular lesions, diffuse metastatic muscle infiltration, multifocal intramuscular calcification, and intramus...