Evaluation of the European Society of Medical Oncology-Magnitude of Clinical Benefit Scale Version 1.1 for the Treatment of Extracranial Oligometastatic Non-Small Cell Lung Cancer With Radiosurgery.

[PURPOSE] The European Society of Medical Oncology (ESMO) magnitude of clinical benefit scale (MCBS) version 1.1 is an evaluation scale that was developed to evaluate the MCBS reported in clinical research studies of cancer treatments. The American Society for Radiation Oncology (ASTRO) and the European Society for Radiotherapy and Oncology (ESTRO) created joint guidelines for the use of local therapy in the management of extracranial oligometastatic non-small cell lung cancer (NSCLC). We applied the ESMO-MCBS v.1.1 to evaluate the clinical benefit reported in studies that informed the ASTRO/ESTRO guidelines.

[METHODS AND MATERIALS] We applied the ESMO-MCBS v1.1 to the 23 studies identified by the ASTRO/ESTRO taskforce. As well, we evaluated the recently published Consolidative Use of Radiotherapy to Block Oligoprogression study and Stereotactic Radiotherapy for Oligo-Progressive Metastatic Cancer Trial, for a total of 25 studies evaluated. All evaluated studies were graded by at least 3 of the authors. Any discrepancies were subsequently reviewed by the scoring authors.

[RESULTS] The addition of stereotactic body radiation therapy to all sites of oligometastatic disease in combination with standard-of-care chemotherapy was associated with substantial improvements in survival. These studies resulted in a score of 4 using form 2a (noncurative treatment with overall survival from standard therapy between 12 and 24 months). Of the 10 prospective single-arm studies, 9 received a score of 3 using form 3, due to progression-free survival exceeding 6 months. No studies received a score of 5 (highest clinical benefit).

[CONCLUSIONS] The use of local radiation in the treatment of extracranial oligometastatic NSCLC is associated with a substantial clinical benefit, according to the ESMO-MCBS v1.1. Radiation therapy was comparable to established and groundbreaking targeted therapies such as pembrolizumab in combination with pemetrexed for epidermal growth factor receptor and anaplastic lymphoma kinase-negative NSCLC, and osimertinib for epidermal growth factor receptor-mutated NSCLC. MCBS would be even higher if quality-of-life improvements are found in future trials.