Virtual Library
Start Your Search
H. Hirakawa
Author of
-
+
P2.03 - Chemotherapy/Targeted Therapy (ID 704)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Chemotherapy/Targeted Therapy
- Presentations: 1
- Moderators:
- Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
-
+
P2.03-011 - Correlation and Problems of Re-Biopsy and Liquid Biopsy for Detecting T790M Mutation (ID 8039)
09:30 - 09:30 | Author(s): H. Hirakawa
- Abstract
Background:
T790M mutation test by the approved in vitro diagnostic agent (cobas v2.0) is essential for the use of osimertinib and opportunities for re-biopsy are increasing.
Method:
Success rate and T790M mutation detection rate were retrospectively investigated in 22 cases of 18 patients who took resistance to the 1st and 2nd generation EGFR-TKI at the Saga University Medical School Hospital and underwent re-biopsy. T790M with plasma DNA was examined by MBP-QP, a highly sensitive detection system developed in our laboratory, and cobas v2.0.
Result:
All patients were adenocarcinoma and the mutation status was 8 patients of del 19 and 10 patients of L858R. Re-biopsy sites were 7 bones, 4 primary sites, 3 cases of liver, pleura, lymph nodes, and 2 other sites, respectively, and surgical excision was 31.8%, median time to biopsy from informed consent was 10.5 days (range:1-39). The success rate was 95.5% and the T790M detection rate by cobas v2.0 was 52.3% for all cases, and there was no significant difference between 55.6% for del 19 and 50.0% for L858R. The plasma T790M detection rate using MBP-QP collected at the same time was 65.0% for all cases and there was no significant difference between 55.6% for del 19 and 72.7% for L858R. We experienced one case of atypical angina as a serious complication. Case presentation: ≪No.1≫ First biopsy as re-biopsy (bone): cobas method was negative and MBP-QP method was positive and could not be administered with osimertinib. Second biopsy as re-biopsy (liver): both cobas method and MBP-QP method were positive and could be administered with osimertinib and had a remarkable response. ≪No.2≫ Axillary lymph node biopsies were performed twice, but cobas method was negative and MBP-QP method was positive, and osimertinib could not be administered. Thereafter, hepatic metastasis was biopsied, but both cobas method and MBP-QP method were negative. When plasma specimens by cobas method were tested after insurance approval, plasma T790M was positive, and osimertinib could be finally administered. Although it was effective for axillary lymph node metastases, it had no effect on liver metastases.
Conclusion:
The sensitivity of the test method and the tumor heterogeneity between individuals may influence the detection of T790M mutation. In order to reliably administer osimertinib to patients with indication, it is desirable to establish an appropriate time and site for re-biopsy, and establish examination methods.
