P50 A Case of a Patient Harboring an EGFR -T790M Mutation Positive in Squamous Cell Lung Cancer

Abstract

Actually, the treatment of lung cancer who express driver mutations consist in block this target, the majority of this patients has an adenocarcinoma histology only few of them has the squamous type. We describe a case report of a 58-year-old female, non-smoker, with a persistent cough of 2 months of evolution. On May 2016, the CT scan reported lesion of 72x56mm in right segment 6, infiltration of hilum, pulmonary artery and mediastinal adenopathies. No extrathoracic disease. Biopsy: squamous cell carcinoma. Since the lesion was considered unresectable, she initiates concurrent ChT-RT (cisplatin / gemzar). After the 4th application, local progression was evidenced. Mutation studies, showed EGFRm Exon 19. She starts treatment with Afatinib (40mg / d) but, after 2 weeks, presented G3 gastrointestinal toxicity, so a dose-adjustment to 30mg / d was performed, G2 dermal toxicity also was reported. By December 2016, due to the response obtained, a medial and inferior lobectomy was performed. Pathological report (PR): middle lobe: pneumonitis. Lower lobe: squamous carcinoma. T: 3.5cm, G1, LVI (+), parenchymal margin (+). A PET / CT scan 4 weeks after the surgery, demonstrating right parahilar hypermetabolic lesion, pleural nodules and subcarinal adenopathy. The systemic treatment was restart in January 2017 with erlotinib 150mg /d. A PET / CT control 2 months later just showed slight metabolism in subcarinal adenopathy. She remains asymptomatic until October 2017, when presented aphasia and behavioral alterations. MRI: single left cortico-subcortical lesion of 2.2 x 2 cm with edema and subfalcial herniation. An hypo-fractionated radiotherapy scheme with corticoids was programmed but with minimal benefit. Six weeks after having completed RT (December 2017), greater neurological involvement is evidenced associated with weakness in lower limbs. MRI: lesion of 17.6 x17.3mm with contrast hyper-uptake and edema. CT thorax: no evidence of disease. Considering these findings and clinical deterioration a cerebral metastasectomy was performed. PR: squamous cell carcinoma. EGFRm deletion 19 (+) T790M (+). Due to the post-surgery clinical deterioration, the patient did not receive systemic treatment until March 2018, CT scan: multiple subcarinal adenopathies, contralateral pulmonary nodules and a 6mm nodule in the right lobe of the cerebellum. Patient is currently under treatment with osimertinib, with clinical neurological recovery and no respiratory symptoms. The use of TKI in SQCLC has a benefit in this patient, but the magnitude of this could be lower than adenocarcinoma according with a few series. However, this does not seem to be the case.