The importance of EGFR mutation testing in squamous cell carcinoma or non-small cell carcinoma favor squamous cell carcinoma diagnosed from small lung biopsies

Abstract

Background Adenosquamous carcinoma (ADSC) of the lung, a rare but aggressive subtype of non-small cell lung cancer (NSCLC), is defined as a carcinoma containing components of adenocarcinoma (ADC) and squamous cell carcinoma (SqCC). Mutations of epidermal growth factor receptor (EGFR) are found at a frequency of 15 to 44% in Asian ADSC, and EGFR tyrosine kinase inhibitors (EGFR-TKIs) are a more effective treatment for EGFR-mutated ADSC compared to chemotherapy. However, ADSC in small lung biopsies could be misdiagnosed as SqCC or non-small cell carcinoma (NSCC) favor SqCC due to undersampling, which may result in neglecting of EGFR mutation testing and affecting patients’ clinical management, particularly in Asian patients that relatively have high prevalence of EGFR mutation. Methods A total of 148 small lung biopsy cases with pathological diagnosis of SqCC or NSCC favor SqCC were retrospectively enrolled. The frequency of EGFR mutations and the correlation between patients’ EGFR mutation status and clinicopathological characteristics were evaluated. Results EGFR mutations were found in 8.8% (13 /148) of all cases with 5.2% (7/135) in SqCC and 46.2% (6/13) in NSCC favor SqCC. There were 7 (53.8%) L858R mutation, 4 (30.8%) exon 19 deletions, and 2 (15.4%) cases with coexistent L858R and T790 M mutations. Multivariate analysis showed that EGFR mutations were more prevalent in never-smokers (83.3% versus 16.7%, p = 0.006) and patients diagnosed as NSCC favor SqCC (46.2% versus 5.2%, p = 0.001). Moreover, 75% (3/4) of EGFR mutation-positive cases with subsequent surgical resection or rebiopsy were further diagnosed as ADSC. Conclusions EGFR mutation testing should be performed in Asian patients with SqCC diagnosed from small lung biopsies, especially in never-smokers and patients with diagnosis of NSCC favor SqCC, which have a high probability of being ADSC.

Real-World Characteristics and Outcomes of Advanced Non-Small-Cell Lung Cancer Patients with EGFR Exon 19 Deletions or Exon 21 Mutations

“…EGFR mutations in patients with non-small-cell lung cancer (NSCLC) determine clinicopathology, prognosis and treatment strategies [2] and occur in 10-20% of Caucasian patients and 40-60% of Southeastern Asian patients with lung carcinoma [2]. In general, deletions in exon 19 (ex19del) and the point mutation in exon 21 (Leu858Arg) account for 90% of EGFR mutations in this disease setting [3], with ex19del accounting for 45% of patients and exon 21 (Leu858Arg) accounting for 40% of patients [4]. However, the rates of these mutations can vary by region [2,5], with exon 21 (Leu858Arg) being more prevalent in Asian countries, particularly in Japan [6,7].…”

Osimertinib for compound EGFR exon 19 deletion/T790M mutated lung squamous cell carcinoma

“…They concluded that EGFR mutation testing should be performed in Asian patients with SqCC diagnosed from small lung biopsies, especially in never-smokers and patients with diagnosis of NSCC favor SqCC, which have a high probability of being adenosquamous carcinoma. 17 Tests of multiple biopsies are helpful for accurate pathological and molecular diagnosis. In our case, the patient was a young, light smoker, and diagnosis came from small biopsy.…”

Determination of EGFR Mutation Prevalence in Advanced and Metastatic Lung Squamous Cell Carcinoma in Vietnam

“…Đa số bệnh nhân trong nghiên cứu là nam giới (90,9%), gấp khoảng 10 lần với bệnh nhân nữ giới. Trong nghiên cứu của Amit Joshi và cs (2017), phần lớn đối tượng nghiên cứu là nam giới, gấp khoảng 3 lần so với nữ giới; còn nghiên cứu Hsiang-Ling Ho và cs (2019) thì số lượng nam giới và nữ giới tương đương nhau [8,9]. Với mẫu mô FFPE, các mẫu chủ yếu được lấy bằng phương pháp sinh thiết (96,4%) và tại vị trí u phổi nguyên phát (87,8%).…”

“…Với mẫu mô FFPE, các mẫu chủ yếu được lấy bằng phương pháp sinh thiết (96,4%) và tại vị trí u phổi nguyên phát (87,8%). Nghiên cứu được báo cáo bởi Hsiang-Ling Ho và cs (2019) cho thấy 8,8% (13/148) tổng số bệnh nhân ung thư biểu mô tuyến vảy và ung thư biểu mô vảy có đột biến gen EGFR, trong đó 53,8% đột biến L858R trên exon 21, 30,8% là đột biến xoá đoạn trên exon 19 và 15,4% là đột biến kép L858R trên exon 21 và T790M trên exon 20 [9]. Một nghiên cứu khác của Amit Joshi và cs (2017) báo cáo rằng tỷ lệ đột biến gen EGFR ở bệnh nhân UTBMV là 4,5% (29/639).…”