Do you have a maximum size cutoff for lung SBRT in central NSCLC?

The bigger the tumor size, the lower the efficacy of SBRT. Typically, I wouldn’t treat lesion of size >7 cm for the following reasons:

1. The local control is lower even with BED>100 Gy;
2. There is high chance that the PTV overlaps with critical structures so toxicities could be high.
3. There is high possibility of occult lymph node involvement and distant metastasis so we need to balance toxicities due to high dose RT vs high chance of regional/distant recurrences.
4. There is no much data about SBRT fo...

This question regarding appropriateness for lung SBRT has many components which I will break down one at a time. Regarding tumor sizes 5 cm and greater, we are comfortable offering a lung SBRT approach. As long as the OAR constraints we standardly use for our smaller tumors are met, then we feel comfortable treating this way. We published our retrospective review for this cohort of patients [Woody et al., PMID 25841625]. The conclusions were that: "Lung SBRT for medically inoperable node-negativ...

Technically, large T3 lesions (up to 7cm) were included in the protocols and studies, however, their numbers weren't well represented.

Anything above 7 cm would be a T4 lesion and I would favor chemorads followed by a year of imfinzi if the patient is eligible.

This is an interesting question which I have been addressing. As many may know, during our phase I dose escalation study in Indiana in the early 2000's we had two separate escalation strata, one being for tumours >3 cm and reached a dose of 2400cGy X 3 fractions (7200cGy total) without inhomogeneity corrections. We felt this was the DLT level using the dosimetry employed at the time. Like all larger tumours, you tend to lose conformality, the larger the volume. Nonetheless, I now have no max siz...

I do not have a maximum size cutoff for SBRT for either peripheral or central SBRT. My decision on using SBRT is based predominantly on whether I can meet safe dose constraints. This often becomes challenging for tumors >5-7 cm, depending on tumor location and patient anatomy/lung volume. Once I am not able to meet safe dose constraints, I consider either a hypofractionated approach with 60 Gy in 15 fractions, or concurrent chemoradiation with a conventional 60/30, particularly for tumors on the...

To me, it’s an issue of dosimetry. If you can achieve dose constraints, you’re fine with any size tumor. It’s certainly more difficult as they get bigger and I am more likely to use an 8 or 10 fraction course.