Detection of Rare Mutations in EGFR-ARMS-PCR-Negative Lung Adenocarcinoma by Sanger Sequencing

PURPOSE: This study aimed to identify potential epidermal growth factor receptor (EGFR) gene mutations in non-small cell lung cancer that went undetected by amplification refractory mutation system-Scorpion real-time PCR (ARMS-PCR). MATERIALS AND METHODS: A total of 200 specimens were obtained from the First Affiliated Hospital of Guangzhou Medical University from August 2014 to August 2015. In total, 100 ARMS-negative and 100 ARMS-positive specimens were evaluated for EGFR gene mutations by Sanger sequencing. The methodology and sensitivity of each method and the outcomes of EGFR-tyrosine kinase inhibitor (TKI) therapy were analyzed. RESULTS: Among the 100 ARMS-PCR-positive samples, 90 were positive by Sanger sequencing, while 10 cases were considered negative, because the mutation abundance was less than 10%. Among the 100 negative cases, three were positive for a rare EGFR mutation by Sanger sequencing. In the curative effect analysis of EGFR-TKIs, the progression-free survival (PFS) analysis based on ARMS and Sanger sequencing results showed no difference. However, the PFS of patients with a high abundance of EGFR mutation was 12.4 months [95% confidence interval (CI), 11.6−12.4 months], which was significantly higher than that of patients with a low abundance of mutations detected by Sanger sequencing (95% CI, 10.7−11.3 months) (p < 0.001). CONCLUSION: The ARMS method demonstrated higher sensitivity than Sanger sequencing, but was prone to missing mutations due to primer design. Sanger sequencing was able to detect rare EGFR mutations and deemed applicable for confirming EGFR status. A clinical trial evaluating the efficacy of EGFR-TKIs in patients with rare EGFR mutations is needed.

Clinical analysis of 36 cases of advanced non-small cell lung cancer (NSCLC) with performance status (PS) scores between 2 and 4 / 中华肿瘤杂志

Objective@#To analyze the treatment of advanced non-small cell lung cancer (NSCLC) with performance status (PS) scores between 2 and 4, in order to improve the diagnosis and treatment of these patients.@*Methods@#A total of 36 patients with advanced NSCLC with hypoxemia were reviewed. The clinical data of disease characteristics, etiology, complications, manifestation, therapy, progression, and secondary biopsy were collected. The clinical efficacy was graded according to the Response Evaluation Criteria In Solid Tumors (RECIST): complete response (CR), partial response (PR), stable disease (SD) and disease progression (PD).@*Results@#All patients had hypoxemia, of whom 86.1% (31 patients) had complications and 55.6% (20 patients) had noninvasive ventilator for respiratory support. 77.8% (28 cases) received broad-spectrum antibiotic treatment, and 78.6% of them got lung osmotic relief after the anti-infection treatment. 15 cases received bedside fiberoptic bronchoscopy suction, of whom two cases were treated with airway stent deposition due to airway obstruction, four cases with thoracic drainage, four cases with anticoagulation, and one with thrombolytic therapy. After these supportive treatment, the PS score of these patients decreased from 3.4±0.5 to 2.5±0.7, while SPO2 improved from (89.0±5.2)% to (95.0±3.5)%. As first-ling anti-cancer treatment, nine patients were administrated with targeted medicine orally, 13 patients with a combined chemotherapy of pemetrexed plus bevacizumab or carboplatin, eight patients with paclitaxel plus carboplatin, four patients with gemcitabine plus carboplatin, and two patients with docetaxel plus gemcitabine. In the first response evaluation, there were one case of CR, 23 cases of PR, four cases of SD, and eight cases of PD, with a clinical benefit rate of 66.7% and a disease control rate of 77.8%. A total of 22 patients experienced disease progression, of whom eight cases had a secondary biopsy and six cases had gene sequencing. Of these 36 patients, 10 (27.8%) patients survived at the last follow-up, with a progression-free survival of (10.0±6.5) months.@*Conclusion@#Besides prompt anti-cancer treatment and best supportive treatment should be incorporated to improve PS and improve outcome.