This is a study involving patients with recurrence, metastasis, or new primary malignancies in the thorax requiring radiation and who have previously received radiotherapy to the thorax, where re-irradiation is expected to exceed the dose constraints used for de novo treatments.
Currently, when this group of patients needs another set of radiotherapy, there is a dose limitation based on a percentage of the previous treatment's dose. However, this dose often limits the effectiveness of repeated treatment, with little scientific support for such. Therefore, this study aims to determine the maximally tolerated dose of reirradiation in the thorax, with dose escalation implemented by sequentially increasing the normal tissue recovery factors (i.e. repair factors) to the previously delivered dose.
Using a recovery factor equation associated with a 35% or lower rate of grade 3-5 treatment-related toxicity occurring within 1 year of treatment, accrual will start at level 1 (recovery factor = 10% at 6 months + 0.75% per month thereafter). Patients will be assigned to recovery factors using the TITE-CRM model. The model will use all available information from previously accrued patients to assign the highest dose with a predicted risk of grade 3-5 toxicity of 35% or less.
Pathologically (histologically or cytologically) proven diagnosis of malignancy, with disease in the thorax requiring re-irradiation for any treatment intent. This may include primary lung cancer of any type, esophageal cancer, recurrences, and/or metastasis from any primary. The intrathoracic disease at the time of enrollment does not itself require a biopsy if a prior biopsy has been obtained at that location or another body site. If the risk of biopsy is unacceptable and there is no prior confirmation of malignancy even at the time of the initial course of radiation, enrollment is permitted provided that the case is discussed at a multidisciplinary tumor board or peer-review rounds.
Must have received prior photon thoracic radiotherapy ≥ 6 months ago
Life expectancy > 6 months.
Eastern Cooperative Oncology Group (ECOG) performance status 0-2
Persistent toxicity from previously delivered radiation therapy
Prior development of symptomatic radiation pneumonitis or immunotherapy-related pneumonitis from previous treatment, even if resolved
Cumulative radiation dose for all organs-at-risk is already below dose constraints without a recovery factor applied, or with a recovery factor less than the current dose level of the trial. This will be confirmed by the enrolling team after the planning is completed.
The reirradiation dose-limiting structure is expected to be spinal cord, chest wall, and/or stomach.