Results of Radiation Therapy as Local Ablative Therapy for Oligometastatic Non-Small Cell Lung Cancer

Oligometastatic cancer is characterized by a limited number of metastatic deposits. Compared with lung cancer patients who have more widespread disease, oligometastatic lung cancer patients have more favorable survival outcomes. Therefore, it has been hypothesized that local ablative therapy (LAT) directed at the metastatic deposits in addition to standard-of-care systemic therapy may further improve survival outcomes in oligometastatic lung cancer patients. One LAT modality that has been utilized in oligometastatic lung cancer is radiation therapy. In particular, ultra-hypofractionated radiotherapy, also known as stereotactic body radiotherapy (SBRT), has been shown to provide excellent local control with a favorable safety profile. Here, we reviewed the retrospective studies and prospective trials that have deployed radiation therapy as LAT in oligometastatic lung cancer, including randomized studies showing benefits for progression-free survival and overall survival with the addition of LAT. We also discuss the impact of targeted therapies and immunotherapy on radiation as LAT.

Combination of Local Ablative Therapy and Continuation of Immune Checkpoint Inhibitor (ICI) Therapy Provides Durable Treatment Response Past Oligometastatic Progression in NSCLC: A Case Report

Adenosquamous carcinoma is a rare type of non-small cell lung cancer associated with advanced disease and poor prognosis. There is limited data for the management of mixed histology disease in elderly or frail patients. A 79-year-old woman with no smoking history presented with a right upper lobe lung mass on chest x-ray. Biopsy of the mass demonstrated an EGFR-amplified, PD-L1 positive adenosquamous lung cancer. The mass was surgically resected but the patient was not a candidate for adjuvant chemotherapy. The patient later developed a metastatic paraspinal lesion that was successfully managed with SBRT. Approximately six months later, the patient developed adrenal metastases and pembrolizumab was initiated. After three cycles of systemic therapy, she developed subcutaneous lesions in her back and chest wall, which were managed with palliative resection. Scans demonstrate stable disease and continued responsiveness to pembrolizumab over one year from the most recent local ablative therapy. This case illustrates the potential role of local ablative therapy for oligometastatic progression, as it may confer significant benefit in elderly patients or those with a more indolent disease course. Additionally, we have demonstrated that continuing immunotherapy past progression is reasonable in patients with no viable alternate therapy options, as delayed responses may occur.