Non small cell lung cancer (NSCLC) account for more than 80% of lung cancer cases.
Among those, approximately 7.4% of non small cell lung cancer (NSCLC) patients will have brain metastases (BM) at presentation 2) , and between 20–40% of Non small cell lung cancer (NSCLC) patients will develop intracranial metastases 3) 4).
The concept of “oligometastasis” has emerged as a basis on which to identify patients with stage IV Non small cell lung cancer (NSCLC) who might be most amenable to curative treatment. Limited data have been available regarding the survival of patients with node-negative oligometastatic NSCLC.
Of 802 patients with non-small cell lung cancer who underwent primary staging by a single-day protocol of whole-body PET/CT plus brain PET/MR, 72 cases with adenocarcinoma and brain metastases were enrolled for a prognostic analysis of OS. On the basis of the available follow-up brain status, only 52 patients were eligible for prognostic analysis of nTTP. Metastatic brain tumors were identified on post-contrast MR imaging, and the tumor-to-brain ratio (TBR) was measured on PET images.
Multivariate analysis revealed that FDG-PET findings and eligibility for initial treatment with targeted therapy were significant independent predictors of nTTP and OS. A new index, termed the molecular imaging prognostic (MIP) score, was proposed to define three disease classes. MIP scores were significant predictors of both nTTP and OS (P < 0.001). Pre-existing prognostic indices such as Lung-molGPA scores were significant predictors of OS but did not predict nTTP.
When staging is performed with whole-body PET/CT plus brain PET/MR, this new prognostic index may be helpful to stratify the outcomes of patients with lung adenocarcinoma and brain metastases. The superior prognostic power of this index for nTTP might be used to select appropriate patients for intracranial control and thereby achieve better quality of life 7).
Consecutive patients with advanced NSCLC who attended Kindai University Hospital between January 2007 and January 2016 were recruited to this retrospective study. Patients with regional lymph node-negative disease and a limited number of metastatic lesions (≤5) per organ site and a limited number of affected organ sites (1 or 2) were eligible.
Eighteen patients were identified for analysis during the study period. The most frequent metastatic site was the central nervous system (CNS, 72%). Most patients (83%) received systemic chemotherapy, with only three (17%) undergoing surgery, for the primary lung tumor. The CNS failure sites for patients with CNS metastases were located outside of the surgery or radiosurgery field. The median overall survival for all patients was 15.9 months, with that for EGFR mutation-positive patients tending to be longer than that for EGFR mutation-negative patients.
Cure is difficult to achieve with current treatment strategies for NSCLC patients with synchronous oligometastases, although a few long-term survivors and a smaller number of patients alive at last follow-up were present among the study cohort. There is an urgent clinical need for prospective evaluation of surgical resection as a treatment for oligometastatic NSCLC, especially negative for driver mutations 8).