How do you decide which dose/fractionation to use for consolidative therapy to the lung in patients with oligometastatic NSCLC who have responded well to first-line systemic therapy?

Does the site of oligometastasis matter (ex. brain v bone)? In this trial https://www.ncbi.nlm.nih.gov/pubmed/27789196 20% of patients were treated with SBRT and 56% were treated with intermediate or standard fractionated radiotherapy to the lung (RT details in Appendix Supplementary Table S2).

2 Answers

Mednet Member

Radiation Oncology · University of Colorado School of Medicine

Answered on

For the first part of the question, I broadly think of two groups of patients

1) Lung nodule suitable for SBRT: would then do something like 54 Gy in 3 or 50 Gy in 5 depending on the location

2) Stage III, ie primary in lung and mediastinal nodes: would then do something like 45 Gy in 15 fractions.

The next part of the question is asking about dose/fractionation for oligometastatic disease to other sites. For brain oligometastases I do SRS (either single 20 Gy or 27 Gy in 3). For spine I have been doing either SRS 24-27 Gy in 3 fractions if possible. For other bone locations I have been treating more like 30-35 Gy in 5 fx. So I think it does matter what site is being targeted. What is lacking from my answer is explaining the "rationale". It is really based on personal experience using dose/fractionation regimens in other protocols. I think using the current NRG protocol as a guide is very helpful.

Mednet MemberInvited Expert

Radiation Oncology · University of Rochester

Answered on

I agree with @Dr. First Last. There really is not a correct answer to this question since it depends on the patient and their disease. The ultimate goal is to offer local control and minimize toxicity risks. This becomes a judgement call- and relying on published data, ongoing protocols and personal experience is the only way to approach it. The multi-institutional randomized study (Gomez et al.,) allowed SBRT, 15-fraction hypofractionated RT and chemoradiation. In the literature you will find all types of dose fractionation schedules for oligometastases and primary N0 NSCLC (inlcuding many non-US studies that report 6, 7, 8-fraction regimens). We continue to use a 10-fraction regimen (5-6 Gy x 10) for patients with bulky disease and/or disease compressing normal tissue (is esophagus, brachial plexus ...). MDACC has also reported on their 10-fraction (7 Gy x 10) experience. As Dr Gaspar mentioned, if you are treating 'thoracic Stage III' disease, then you might opt for a more conventional or slightly hypofractionated approach.