Abstract: There are increasing numbers of synchronous multiple primary lung cancer (SMPLC) patients in clinical practice, with most lesions presenting as ground-glass opacity (GGO). For SMPLC patients, surgical resection should be a prior option for all lesions suspected of being malignant, if medically and technically feasible. However, it is frequently a dilemma for the management of residual GGO lesions that were unresected simultaneously with the main tumor in SMPLC patients. We report a case of SMPLC, in which the patient underwent surgical resection of the major lesion with EGFR mutation and then received compelling EGFR-TKI treatment for one enlarging residual GGO lesion after 12 months since operation. Furthermore, a comprehensive literature review about the risk for the progress of GGOs unresected simultaneously with the main lesion and the management of these residual GGOs was also summarized. With the treatment of EGFR-TKI gefitinib for 3 months, the biggest residual GGO lesion (more than 10mm) achieved a complete response (CR), three lesions reduced in size, and the other three lesions remained stable in this case. Surgical resection for major lesion and EGFR-TKI treatment on unresected GGOs might bring favorable outcome for patients with EGFR-mutated multifocal lung cancer. This strategy is safe and effective, which could be a promising therapeutic approach for unresectable GGO lesions in EGFR-mutated SMPLC patients after primary surgery. Notably, folate receptor-positive circulating tumor cell (FR⁺-CTC) for therapeutic monitoring was more sensitive for GGO-featured lung adenocarcinoma than serum markers.
Keywords: multiple primary lung cancer, ground-glass opacity, epidermal growth factor receptor-tyrosine kinases inhibitor, folate receptor-positive circulating tumor cell, literature review