Stereotactic Body Radiotherapy (SBRT) for Reirradiation of Inoperable Lung Lesions

Stereotactic Body Radiotherapy (SBRT) for Reirradiation of Inoperable Lung Lesions: an Italian Multicenter Retrospective Analysis (STRILL IT)

Radiotherapy (radiation treatment) is often used to treat lung cancers and lung tumors that have spread from other cancers. It can be very effective, especially in early-stage lung cancer or when there are only a few tumor sites. Even so, some patients later develop a local recurrence, meaning the cancer comes back in the same area that was previously treated with radiation.

When this happens, treatment options are limited. Surgery can sometimes remove the recurrent tumor, but many patients are not able to have surgery because of their general health or because the tumor is difficult to remove. For these patients, a second course of radiotherapy (called re-irradiation) may be the only possible treatment. One type of radiotherapy, called stereotactic body radiotherapy (SBRT), delivers very high doses of radiation very precisely. SBRT has been used successfully as a second treatment after standard radiotherapy in some patients. However, there is very little information about using SBRT again in patients who already received SBRT the first time.

Because only small studies have been done and the patients were very different from each other, doctors still do not know enough about how safe and effective a second SBRT treatment is. In particular, it is still unclear whether giving another high-dose radiation treatment is possible without causing serious side effects. More research is needed to better understand this option and help guide treatment decisions for patients.

Inclusion Criteria:

• Inoperable primary non-small cell lung cancer or other metastatic primaries with lung metastases, already treated with radical dose SBRT
• Inoperable local recurrence (defined as a tumor recurrence overlapping the 50% isodose field) confirmed by documented radiographic findings and/or pathological biopsies within the thoracic area
• Patients had previously received curative intent SBRT with a biologically equivalent dose equal or higher than 75 Gy
• Stereotactic reirradiation with ablative purposes up to 8 fractions
• No active distant metastasis or controlled distant metastasis at the time of re-irradiation
• More than 12 months from previous SBRT
• PS ≤ 2

Exclusion Criteria:

• Previous conventional RT
• Reirradiation with palliative doses
• Reirradiation with conventionally fractionated or mildly hypofractionated RT