Predictors of Local Control for Stereotactic Ablative Radiotherapy (SAbR) in Pulmonary Oligometastases from Gastrointestinal Malignancies

Abstract

Background/Aim: To assess predictors of local control (LC) for stereotactic ablative radiotherapy (SAbR) in pulmonary oligometastatic disease (OMD) from gastrointestinal (GI) malignancies. Patients and Methods: Patients with pulmonary OMD treated with SAbR from January 2016 to December 2018 were included in this observational analysis. Primary endpoint was LC. Uni-and multivariate analyses to assess variable correlations were conducted. Results: Thirty-seven patients and 59 lung metastases were evaluated. The delivered dose was 30-60 Gy in 3-8 fractions. After a median follow-up of 23.0 months (range=6.3-50.4 months), LC rate at 1/2 years was 89.7%/85.0%, and increased to 96.0%/91.0% for lesions treated with a biologically effective dose (BED 10 ) ≥100 Gy (p=0.03). RECIST response at 6 months was predictive for LC (p=0.002). Conclusion: SAbR is an effective option for pulmonary OMD from GI malignancies. A BED 10 ≥100 Gy and radiological response at 6 months can affect LC.Oligometastasis, a term first introduced in 1995, refers to a limited metastatic state with a small number of lesions and involved organs (1). The notion of oligometastatic disease (OMD) has dramatically changed the concept and therapeutic approach to metastatic cancer (2). Even if systemic therapy remains essential, these patients seem to benefit from local therapy (e.g. surgery and radiation therapy), and multimodality approach is considered potentially able to improve oncological outcomes in selected OMD cases (3). Lung parenchyma represents a common site for oligometastatic seeding. Notably, in a series of 575 patients and 708 lung metastasectomies, 35.6% resulted from gastrointestinal (GI) tumors (4). Surgery represents a mainstay of treatment for lung oligometastasis, resulting in long-term disease control and survival (5). More recently, stereotactic ablative radiotherapy (SAbR), also referred to as stereotactic body radiotherapy (SBRT), has emerged as a consistent alternative to surgery, with reported promising local control and acceptable toxicity (6)(7)(8)(9)(10)(11)(12)(13)(14)(15).Based on this background, we aimed at performing a novel analysis of the efficacy of using SAbR in a cohort of pulmonary OMD from GI malignancies. Factors potentially affecting LC were analyzed. Patients and MethodsStudy design. Patients treated with SAbR for lung OMD from GI cancers between January 2016 and December 2018 were included in this analysis. Each case was discussed by the institutional multidisciplinary tumor board including dedicated Radiation Oncologists, Medical Oncologists, Thoracic and General Surgeons, Pathologists and Diagnostic Radiologists. Indications for SAbR were as follows: oligometastasis and oligorecurrence, treatment of all pulmonary lesions (≤5 lung lesions); oligoprogression and oligopersistence, treatment only of progressive/active lesions after chemotherapy (≤5 lung lesions). In the latter case, the treatment goal was to obtain local control and prevent or delay any change in systemic therapy (CST). All treated patients ga...

Camrelizumab and Apatinib Combined with Radiotherapy Is Effective in Advanced Oligometastatic Non-Small-Cell Lung Cancer

“…The idea of oligometastases was first proposed in 1995 [ 5 ], which believed that cancer in this stage was only limited to one or a few targeted metastases. At present, there is no standard for the definition of oligometastases, but the European Society of Oncology and some recent studies believe that as long as the location of the metastases and the number of metastatic tissues (< 5), oligometastases can be confirmed by a complete radiological examination [ 6 , 7 ]. Oligometastasis is a transitional period in which the local primary tumor spreads to a larger area, and it has the potential to be cured.…”