Abstract 492P
Background
The third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib is a standard treatment in case of T790M mutation positive after failure to first or second generation EGFR TKI in patients with EGFR-mutant non-small cell lung cancer (NSCLC). We investigated a success rate of rebiopsy and sequential EGFR TKI treatment in real world setting in Korea.
Methods
We retrospectively reviewed medical records of patients with EGFR mutant advanced NSCLC who received first- or second- generation EGFR TKI between Jan 2012 and Jun 2018 at a single center in Korea.
Results
Among 221 patients with EGFR-mutant NSCLC, 68 patients who were lost to follow up (n = 19) or still on 1st- or 2nd- generation TKI (n = 49) at time of analysis were excluded. Forty-three out of remaining 153 patients (28%) did not have a chance of consideration for second line treatment because of deterioration of performance status (n = 21) or death (n = 22), especially in elderly over 70 years. Tests for acquired EGFR mutation were performed in 76% (84/110), among which 73 cases were tissue rebiopsy and 11 cases were plasma EGFR mutation analysis. Acquisition of tumor tissue in rebiopsy was successful in 93% (68/73). The most common reason of not doing rebiopsy was lack of sequential treatment options (n = 24). Ten patients with negative T790M or failure at initial rebiopsy underwent more than two times of repeated EGFR mutation analysis, among which four patients had eventually positive T790M at some point of disease course. Overall T790M positive rate was 54% (45/84). Among 7 patients with initially negative T790M mutation in plasma analysis, further rebiopsy from tumor tissue was performed only in one patients because of patient's refusal (n = 2), physician's decision to continue post-progression EGFR TKI (n = 2), poor performance status (n = 1), and unaccessibility to tumor tissue (n = 1).
Conclusions
About 30% of patients with EGFR mutant NSCLC did not have a chance of consideration for second line EGFR TKI treatment, especially in elderly over 70 years. Success rate of tumor tissue rebiopsy was over 90% in real world setting, and repeated rebiopsy may increase detection rate of acquired T790M mutation.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4P - Impact of chemotherapy and radiotherapy on tissue expander or implant removal in breast cancer patients
Presenter: Sungmi Jung
Session: Poster display session
Resources:
Abstract
5P - Long-term prognostic effect of hormone receptor subtype on breast cancer
Presenter: Ki-tae Hwang
Session: Poster display session
Resources:
Abstract
6P - Effect of apparent diffusion coefficient in predicting pathologic responses in patients with breast cancer treated with neoadjuvant chemotherapy using nanoparticle albumin-bound paclitaxel
Presenter: Yutaka Mizuno
Session: Poster display session
Resources:
Abstract
7P - Current diagnostic strategy for mammographic microcalcification without specific ultrasound abnormality
Presenter: Naoki Sato
Session: Poster display session
Resources:
Abstract
8P - Comparison of standard uptake value of 18F-FDG-PET-CT with tumour-infiltrating lymphocytes in breast cancer ≥1cm
Presenter: Soeun Park
Session: Poster display session
Resources:
Abstract
10P - Prognosis and effect of adjuvant treatment in small, node(-), HER2(+) breast cancer
Presenter: Seungtaek Lim
Session: Poster display session
Resources:
Abstract
11P - The prognosis of rare histopathologic subtype of breast cancer
Presenter: Soo Youn Bae
Session: Poster display session
Resources:
Abstract
12P - Daily collection of physical activity via smartphone application and smart band for development of distress screening tools in breast cancer survivors: A feasibility study
Presenter: Yungil Shin
Session: Poster display session
Resources:
Abstract
13P - Breast cancer distribution in East Azerbaijan, Iran: Results of population-based cancer registry
Presenter: Shima Pashaei
Session: Poster display session
Resources:
Abstract
14P - Validation of the optimum timing of assessment of tumour infiltrating lymphocytes during preoperative chemotherapy for breast cancer
Presenter: Shinichiro Kashiwagi
Session: Poster display session
Resources:
Abstract