A 71-year-old never-smoker man underwent left upper lobectomy and thymectomy in July 2018. Pathology reported a (left lung) adenocarcinoma. The tumor invaded the pleura and thymic lymph nodes; thus 6 cycles of pemetrexed 800 mg day 1 (d1) and carboplatin 400 mg (d1) were subsequently delivered until January 2019. Then he accepted the accurate Gamma Knife (GK) radiosurgery to the lesions in the upper left side of the mediastinum (DT 38.4 GY/12F) in February 2019. Then the patient took Chinese medicine to recuperate, the specific details were unknown.
A computed tomography (CT) scan performed 18 months after surgery (January 2020) detected multiple lung and lymph nodes lesions (Fig. 1②-④), and CEA level increased to 14.8 ng/ml, and CA153 level increased to 28.6 µ/ml and CA125 level increased to 47.8 µ/ml. Ultrasound-guided needle biopsy of the intraperitoneal lymph node biopsy was performed on January 23. Pathology reported metastatic adenocarcinoma originated from lung. Immunohistochemically, the tumor cells tested positive for cytokeratin 7 (CK7), NapsinA, Ki-67 (labeling index = 30%), P40, and CKAE1/AE3 and the tumor cells were negative for cytokeratin 20 (CK20) and CK5/6. The next generation sequencing (NGS) was performed and the molecular results from intraperitoneal lymph node tissue biopsy did not show any abnormality (EGFR, KRAS, NRAS, ALK, ROS1, MET, HER-2, FGFR2, NTRK1, NTRK2, RET, PIK3CA) except BRAF exons 15 (p.D594N pathogenicity mutation). The patient developed symptoms of right progressive hypotonia to grade 1 and distortion of right commissure. Magnetic resonance imaging (MRI) of head showed that there was a mass (about 1.3 cm in diameter) in the left frontal lobe with brain edema, which was deemed metastatic (Fig. 1①). Furosemide and 20% mannitol were used to treat cerebral edema and the muscle tension recovered to grade 2. The patient refused the treatment of whole brain radiotherapy and systemic chemotherapy.
The patient started to take trimetinib (2 mg qd po) based on the molecular results from February 2, 2020. There have been systemic pruritus and hand-foot syndrome during the treatment, which was evaluated as grade 2 adverse reaction according to Common Terminology Criteria for Adverse Events (CTCAE) 5.0. and no other adverse reactions were observed. He got relief after taking positive measures. A CT scan performed 8 months after medication (October 15, 2020) showed a partial response of brain metastasis, pulmonary nodule, portal lymph node metastasis and peritoneal lymph node metastasis (Fig. 1⑤-⑧). CEA, CA125, and CA153 all returned to normal level. The improvement of quality of life of the patient depended on the recovery of muscle tension. In November 2020, the patient developed melena without obvious cause, and gastroscopy showed compound ulcer, so he stopped taking trimetinib. The patient eventually died of gastrointestinal bleeding. He had progression-free survival (PFS) of 8 months of trimetinib monotherapy.