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Natasha Rekhtman
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MA09 - Lung Cancer Surgical and Molecular Pathology (ID 908)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Pathology
- Presentations: 2
- Moderators:
- Coordinates: 9/24/2018, 15:15 - 16:45, Room 202 BD
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MA09.04 - Discussant - MA 09.01, MA 09.02, MA 09.03 (ID 14605)
15:30 - 15:45 | Presenting Author(s): Natasha Rekhtman
- Abstract
- Presentation
Abstract not provided
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MA09.06 - The Newly Recognized Filigree Pattern of Micropapillary (MIP) Lung Adenocarcinoma (LADC) is as Clinically Important as the Classical Pattern (ID 11874)
15:50 - 15:55 | Author(s): Natasha Rekhtman
- Abstract
- Presentation
Background
Filigree pattern is a newly recognized addition to the morphological spectrum of the poor prognostic category of micropapillary (MIP) LADC. However, its morphologic features and clinical importance are not well understood. The aim of this study was to investigate the morphologic spectrum and clinical significance of filigree MIP pattern.
a9ded1e5ce5d75814730bb4caaf49419 Method
Filigree pattern was defined as tumor cells growing in delicate lace-like narrow stacks of cells (at least 3 piled-up nuclei) without fibrovascular cores, with frequently visible attachments to alveolar walls. This differs from the 2015 WHO description of classical MIP pattern as tumor cells growing in papillary tufts forming florets that lack fibrovascular cores. In order to assess for filigree vs classical MIP, we documented the frequency and extent of both patterns in 1325 Stage I LADC. These were correlated with recurrence free probability (RFP) and lung cancer-specific survival (LCSS) using Kaplan-Meier analysis.
4c3880bb027f159e801041b1021e88e8 Result
In addition to 87 MIP predominant ADC previously diagnosed, we identified 57 more cases of MIP predominant LADC due to the new criteria of MIP filigree pattern. Of these 57 cases, 37, 16, and 4 cases were reclassified from papillary, acinar, and solid predominant LADCs, respectively. Survival curves of previously diagnosed MIP and newly diagnosed MIP for RFP showed a similar worse prognosis compared to other LADC histologic subtypes (previously diagnosed MIP vs newly diagnosed MIP, 5-year RFP 66% vs 68% [Figure]) as well as LCSS (previously diagnosed MIP vs newly diagnosed MIP, 5-year LCSS 82% vs 85%). When the MIP cases were divided into filigree or classical predominant MIP, no significant prognostic differences were observed between the two groups.
8eea62084ca7e541d918e823422bd82e Conclusion
The lack of significant prognostic difference between filigree vs classical predominant MIP LADC supports our proposal that the filigree pattern is an important addition to the morphologic spectrum of the MIP subtype.
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MA16 - Novel Mechanisms for Molecular Profiling (ID 917)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 13:30 - 15:00, Room 203 BD
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MA16.04 - Clinical and Molecular Characteristics of EGFR Mutant Lung Cancers with Concurrent TP53 and RB1 Mutations. (ID 12513)
13:55 - 14:00 | Author(s): Natasha Rekhtman
- Abstract
- Presentation
Background
20% of patients with metastatic lung adenocarcinoma have activating EGFR-mutations. EGFR-mutant lung cancers can undergo histologic transformation to small cell lung cancer (SCLC) as a response to the selective pressure of EGFR-TKIs in <5% of patients after earlier-generation EGFR-TKIs and have been reported after osimertinib. SCLC nearly universally harbor TP53/RB1-alterations which are rarely seen in EGFR-mutant lung adenocarcinomas. We sought to identify this subset of patients, describe their clinical course and likelihood of SCLC transformation.
a9ded1e5ce5d75814730bb4caaf49419 Method
Retrospective review of targeted next generation sequencing (NGS, MSK-IMACT) at Memorial Sloan Kettering (MSK) was performed to identify patients with concurrent EGFR-activating mutations and TP53/RB1-mutations within the same tumor sample from NGS between April 2014 to February 2018 with a data cutoff of March 2018. For comparison, consecutive patients with lung cancers harboring EGFR-mutations who were EGFR-TKI naïve and TP53/RB1-wildtype were also collected during that time-period.
4c3880bb027f159e801041b1021e88e8 Result
Of the 21% of lung cancer patients with activating EGFR-mutations (759/3662), 5% (40/759) had concurrent TP53/RB1-mutations. 43% (17/40) were female, 58% former-smokers (23/40, median pack-years: 8), and median age of 68 (range 25-86 years). 88% (35/40) were adenocarcinoma at diagnosis, of which 11% (4/35) transformed to SCLC during treatment; 10% (4/40) were de-novo SCLC at diagnosis, and 1 was large cell neuroendocrine. The transformation rate was significantly higher compared to previous work from MSK evaluating EGFR-mutant patients showing 4% (4/155) transformation (p=0.04). Concurrent PIK3CA mutations were more frequently seen in the EGFR/TP53/RB1 mutant group compared to the TP53/RB1-wildtype group (17% (n=6/35) vs 7% (n=4/60), p=0.11). 20 patients were EGFR TKI-naïve at the time of NGS; the median time on EGFR-TKI (ToT) was 7.6 months versus 14.2 months in the TP53/RB1-wildtype group (HR 4.48, p=0.0003). The overall survival (OS) of this cohort versus TP53/RB1-wildtype was not different (4.3 vs 4.1 years, HR 1.35, p=0.51). In the 4 patients with SCLC transformation, the median time to transformation was 2.4 years after a median of 1.5 EGFR-TKI therapies (range 1-5 lines). Median OS from time of transformation was 7 months. 63% (25/40) of the EGFR/TP53/RB1-mutant cohort had brain metastases during their disease course as compared to 50% (n=30) in the TP53/RB1-wildtype group (p=0.30).
8eea62084ca7e541d918e823422bd82e Conclusion
SCLC transformation is enriched in EGFR/TP53/RB1-mutant lung cancers, occurring in 11% of patients. Once SCLC transformation occurs, overall survival is short. Patients with EGFR/TP53/RB1 have a shorter time on EGFR-TKI. Further investigation into optimal treatment for this subset of EGFR/TP53/RB1 mutant lung cancers is critical.
6f8b794f3246b0c1e1780bb4d4d5dc53Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
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MA22 - New Therapeutics, Pathology, and Brain Metastases for Small Cell and Neuroendocrine Tumour (ID 925)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Small Cell Lung Cancer/NET
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 15:15 - 16:45, Room 206 BD
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MA22.05 - Impact of Tumor Spread Through Air Spaces (STAS) in Lung Neuroendocrine Tumors (NETs) (ID 14221)
15:45 - 15:50 | Author(s): Natasha Rekhtman
- Abstract
- Presentation
Background
We have previously reported the prognostic significance of STAS in lung adenocarcinoma and squamous cell carcinoma. The aim of this study was to investigate the incidence and prognostic impact of STAS in lung NETs.
a9ded1e5ce5d75814730bb4caaf49419 Method
We evaluated all tumor slides (range 2-7, median 3) for presence of STAS from patients with p-Stage I-III primary lung NETs [n=628, typical carcinoid (TC, n=305), atypical carcinoid (AC, n=38), large cell neuroendocrine carcinoma (LCNEC, n=93) and small cell lung carcinoma (SCLC, n=57)]. Patients with combined NETs were excluded from this analysis (n=19). Cumulative incidence of recurrence (CIR) and lung cancer-specific cumulative incidence of death (LC-CID) were analyzed by competing risks approach.
4c3880bb027f159e801041b1021e88e8 Result
STAS was identified in 25% of NETs (15% in TC, 37% in AC, 43% in LCNEC, and 46% in SCLC). Prognostic analysis in TC cohort was not conducted due to the small number of events (<5 events). Patients with STAS positive tumors were associated with higher CIR than STAS negative tumors in the total (AC-LCNEC-SCLC) cohort as well as individual AC, LCNEC and SCLC cohorts (Figure 1, A-D). STAS was also associated with higher LC-CID in all cohorts except for AC (Figure 1, E-H). In multivariable analysis, STAS was a significant risk factor for recurrence and lung cancer specific-death, independent of stage and histologic subtype. Stratified by stage, STAS was an independent predictor of recurrence (subhazard ratio [SHR] 2.39, 95% CI 1.26-4.54, p= 0.007) and lung cancer-specific death (SHR 2.42, 95% CI 1.21- 4.84, p= 0.012) in LCNEC. In SCLC, STAS was also an independent risk factor of lung cancer-specific death (SHR 4.06, 95% CI 1.33- 12.35, p= 0.014).
8eea62084ca7e541d918e823422bd82e Conclusion
STAS is a significant prognosticator in individual NET subtypes; AC, LCNEC, and SCLC. STAS is an independent poor prognostic factor in LCNEC and SCLC for lung cancer-specific death.
6f8b794f3246b0c1e1780bb4d4d5dc53Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
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MS10 - Part Solid Nodules, GGN and STAS (ID 789)
- Event: WCLC 2018
- Type: Mini Symposium
- Track: Treatment of Early Stage/Localized Disease
- Presentations: 1
- Moderators:
- Coordinates: 9/24/2018, 15:15 - 16:45, Room 206 F
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MS10.04 - Therapeutic Implications of Spread Through Air Spaces (STAS) (ID 11443)
16:00 - 16:15 | Author(s): Natasha Rekhtman
- Abstract
- Presentation
Abstract not provided
Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
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OA03 - Advances in Lung Cancer Pathology (ID 897)
- Event: WCLC 2018
- Type: Oral Abstract Session
- Track: Pathology
- Presentations: 1
- Moderators:
- Coordinates: 9/24/2018, 10:30 - 12:00, Room 205 BD
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OA03.07 - Three-Dimensional Immunofluorescence Analysis of Dynamic Vessel Co-Option of Spread Through Air Spaces (STAS) in Lung Cancer (ID 14318)
11:35 - 11:45 | Author(s): Natasha Rekhtman
- Abstract
- Presentation
Background
STAS was identified, by the 2015 WHO classification, as a new method of invasion in lung adenocarcinoma, with poor prognosis. Blood vessel co-option is a mechanism by which spreading intraalveolar tumor cells connect to the surrounding vasculature to survive. The aim of this study was to visualize the dynamic mechanism of blood vessel co-option using a high resolution and high-quality 3D reconstruction, and multiplex immunofluorescence (IF).
a9ded1e5ce5d75814730bb4caaf49419 Method
A 3D reconstruction image of a case of invasive lung adenocarcinoma with extensive STAS was performed on the formalin fixed paraffin-embedded (FFPE) block. 150 serial sections were obtained by the automated sectioning system AS410 (DNS. Ltd, Japan), and stained with H&E (100 slides), and multiplex IF (30 slides) for CD31, type IV collagen, TTF-1 and E-Cadherin to assess the relation between STAS and the surrounding lung parenchyma and vasculature. The IF stained sections were scanned with 0.33um/pixel by Panoramic P250 Flash (3D Histech Ltd, Hungary) Whole Slide Imaging Scanner (WSI). The WSIs were reconstructed into 3D exported to Imaris 8.0 (Bitplane, MA, US) for signal assessment.
4c3880bb027f159e801041b1021e88e8 Result
Serial 3D image analysis identifies the presence of STAS mainly in the form of micropapillary clusters. The multiplex IF staining highlighted the co-option which was determined by the spread and then attachment of STAS (TTF-1 and E-Cadherin positive) to distant alveolar wall capillaries (CD31 positive) with preservation of the alveolar wall (figure). This relation between STAS and the surrounding lung parenchyma was visualized in all serial sections of the whole FFPE block thickness.
8eea62084ca7e541d918e823422bd82e Conclusion
The survival of STAS, beyond the tumor edge, in lung adenocarcinoma is a viable mechanism for tumor recurrence. The combination of the high resolution and high-quality 3D reconstruction and multiplex immunofluorescence in our study, supports the concept that dynamic blood vessel co-option is a mechanism for STAS survival.
6f8b794f3246b0c1e1780bb4d4d5dc53Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
