Multifocal lung cancer within ground glass lesions: Are favorable outcomes consequent to surgical resection or inherent to the disease?

Abstract

Multiple primary lung cancer (MPLC) is a phenomenon that appears to be increasing in frequency, perhaps as a result of improved resolution of cross-sectional imaging as well as an aging population of lung cancer survivors. 1,2 The diagnosis of MPLC remains complicated, however, because it must be distinguished from metastatic disease. Although criteria for identifying MPLC have been proposed and standardized, 3,4 we still lack reliable and robust means of clearly discriminating patients with MPLC from those with satellite lesions and other intrapulmonary foci of metastatic disease. 1,2 In their article in this issue of the Journal, Chen and colleagues 1 describe their experience with patients who underwent resection of 2 or more malignant pulmonary lesions, with widely accepted criteria used for MPLC (differing histologic type, or same histologic type with anatomic separation and N<2 M0). 1,3,4 The investigators divided the patients into subgroups, with group A including patients with only ground glass opacity (GGO)-dominant lesions, group B including patients who had primary solid nodules with additional secondary GGOs, and group C including patients whose primary and secondary lesions were all solid in nature. After extracting samples for RNA and DNA evaluation, the investigators assessed for somatic mutations in EGFR, TP53, PIK3CA, and BRAF genes, as well as EML4-ALK, ROS1, and RET fusions. Ultimately, Chen and colleagues 1 sought both to characterize differences in survival among the 3 groups and to examine extent of concordance among driver mutations between tumors within individual patients. In this well-written article, Chen and colleagues 1 describe several important findings. The 5-year recurrence-free survival was best for those with GGOs and worst for those with solid nodules (100%, 68%, and 51% in groups A, B, and C, respectively). Further, such results were paralleled on analysis of the overall 5-year survival (100%, 81%, and 60%, respectively). Chen and

The search for reliable markers of ground glass opacity prognosis: The truth remains largely unknown

“…We are still in our infancy of understanding GGOs, however, and just as it is important to understand how much lung to remove, we are also in need of understanding which GGOs will be adequately managed with alternative modalities (such as ablation or stereotactic radiation), which will require systemic treatment, and which will require no treatment at all. 9…”

Commentary: Ground-glass nodules: The challenge of identifying red flags amidst a background of red herrings

“…The size of the GGO, specifically at 1.05-cm cutoff, was the only factor that correlated with invasive adenocarcinoma, which resonates with the TNM 8 th edition in which size increments at 1 cm translate into survival differences for T1 tumors. 5 The Fudan article adds to the literature in that (1) this is the largest series of pure GGO adenocarcinomas; (2) they excluded atypical adenomatous hyperplasia (AAH) cases and grouped adenocarcinoma in situ with minimally invasive adenocarcinoma together as the preinvasive group to compare with the invasive adenocarcinomas; and (3) they focused on CT density as one of the parameters to differentiate preinvasive from invasive groups.…”

“…Furthermore, in the absence of any solid components of the nodules in this cohort, the notion of surgical resection should again be considered cautiously because it is uncertain if the superior outcomes associated with this finding can be ascribed to aggressive surgical resection or an indolent process at the outset. 4,5 Fu and colleagues 1 should be commended for their large series, important findings, and rigorous analytic methods. As thoracic surgeons, we expect interventions for aggressive disease pathology to be supported by a high preponderance of evidence and data to support associated procedural risks.…”