Analysis of clinicopathological features of seven patients with lung adenocarcinoma translating to small cell lung cancer / 中国肿瘤临床

ABSTRACT

Objective: To analyze the clinicopathological features of small cell lung cancer transformed from lung adenocarcinoma. Methods: We retrospectively analyzed the clinical and pathological characteristics and follow-up data of seven patients who had been diagnosed with small cell lung cancer transformed from lung adenocarcinoma following treatment from January 2014 to December 2018 at the Fourth Hospital of Hebei Medical University. Results: The latest follow-up had been performed on June 1, 2020. The median time of small cell lung cancer transformation from lung adenocarcinoma following treatment was 31 months; the median time of tyrosine kinase inhibitor (TKI) application before transformation is 14 months. Three patients had transformation at the same site as the original. Seven patients had higher levels of neuron-specific enolase (NSE) before transformation. Before the transformation, disease progression mostly occurred at multiple sites, and the lung, bone, brain, pleura, and lymph nodes were commonly affected. In all cases, immunohistochemical indicators after transformation showed that thyriod transcription factor-1 (TTF-1) was positive; Napsin A was negative; Syn, CD56, and AE1/AE3 were positive; Ki67 expression was high; and PD-L1 expression was negative. Genetic testing after transformation showed that six patients had maintained the original mutant EGFR gene. Treatments after transformation were mainly comprehensive, based on chemotherapy. The median progression-free survival time after transformation was 6 months, and median survival time after transformation for five patients who died was 10 months. Conclusions: Once lung adenocarcinoma undergoes transformation to small cell lung cancer, the disease progresses rapidly, and survival time is short. Patients with lung adenocarcinoma due to EGFR E19 mutation who undergo EGFR-TKI therapy are more prone to small cell lung cancer transformation, and the time to transformation generally exceeds 2 years. The sites of disease progression before transformation are often multiple, and NSE is increased. After transformation, patients generally maintain the original EGFR mutation.