Partial Tumor Irradiation and Immunotherapy for Unresectable Lung Cancer

The present study will explore a novel treatment strategy for unresectable lung adenocarcinoma combining a unique unconventional radiotherapy technique for high dose partial tumor irradiation (PTI) sparing the peritumoral immune microenvironment (PIM) with an immune checkpoint inhibitor (ICI)-based immunotherapy. The present study will focus on patients with larger, unresectable bulky lung tumors who previously failed standard of care therapy, or are unsuitable for conventional radio-chemotherapy due to tumor size and volume, and do not have any further therapeutic option left. This concept implies that a very high, ablative radiation dose (typically 20-25Gy per fraction) is delivered exclusively to the central bulky-tumor segment sparing at the same time surrounding PIM and therefore preserving its function. The present study will explore the potential clinical advantages of the above described innovative treatment concept as a rechallenge treatment: following the disease progression during initiated first-line ICI-therapy, or following discontinuation of ICI-therapy, a same previously used agent (ICI) will be added the PTI to boost its immunologic anti-tumor effects. The treatment response will be measured by comparing the progression-free survival 1 (PFS-1) (ICI-therapy alone) and progression-free survival 2 (PFS-2) (combined rechallange PTI-ICI) rates. The primary endpoint will be ∆PFS rate (PFS-2 vs PFS-1) assessed according to the modified iRECIST criteria. Secondary endpoints will include overall survival, toxicity, and exploration and validation of the anti-cancer immunity. Once treatment is completed, follow up will be performed on a regular basis (at 6 and 12 weeks, and every 3 months later on) by CT, MRT or PET-CT imaging to allow for endpoints assessment, or at any time in case of suspected disease progression. Patients will also be followed clinically with history and physical examinations, vital signs, and laboratory examinations as indicated.