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M. Mikubo
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P3.01 - Poster Session with Presenters Present (ID 469)
- Event: WCLC 2016
- Type: Poster Presenters Present
- Track: Biology/Pathology
- Presentations: 1
- Moderators:
- Coordinates: 12/07/2016, 14:30 - 15:45, Hall B (Poster Area)
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P3.01-023 - Quality Assessment of Resampling Specimens in Primary Lung Cancers with Acquired Resistance to the Initial Therapy (ID 5543)
14:30 - 14:30 | Author(s): M. Mikubo
- Abstract
Background:
Most patients treated against molecular targets eventually develop resistance even after an initial dramatic response. Although rebiopsy of tumors at progression provide information for next-line therapy, it is expected that the tumor tissues would be modified by the therapy.
Methods:
We retrospectively examined histologic features in the resampled specimens in lung cancer patients with resistance to the initial therapy. Furthermore, we also analyzed the differences of tumor cell contents and molecular testing performance according to each biopsy site.
Results:
A total of 315 resampled specimens were submitted to pathology department from 260 patients. Of 315 samples, 116 (37%) were obtained from the lung and 96 (30%) from pleural effusion, 42 (13%) from lymph node, 16 (5%) from liver, 12 (4%) from cerebrospinal fluid (CSF), 10 (3%) from pleura and pericardial effusion, 7 (2%) from bone and 6 (2%) from other biopsy sites. When we compared 48 paired lung tissues between initial and rebiopsies, rebiopsy specimens had significantly less extents of tumor cells and more fibrosis than those in initial biopsy, and these differences were statistically significant with digital quantitation. Resampled sites affect the tumor cell extents and those were high in the order of liver, subcutaneous tissue, lymph node and lung biopsy, whereas pleura and bone samples had a tendency to contain a less number of tumor cells. Molecular testing was performed in 272 samples (from 222 patients). Of 272 samples, 223 (82%) were successfully analyzed, whereas 49 samples were unsuitable for the testing due to low tumor-cell content or complete absence of tumor cells. Higher success rates for molecular testing were seen in the liver and lymph nodes and the value of bone was lowest. Resistant T790M mutations were also differently detected and the higher detection rates were seen in liver, pleura and pericardial effusions.
Conclusion:
Resampled specimens had different property in terms of tumor extents, which differed among the biopsy sites. For molecular testing using resampled specimens, the difference should be taken into account.
