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Pascal Alexandre Thomas
MA20 - Thymic Tumors: From Molecular to Clinical Results and New Challenges in Other Rare Thoracic Tumors (ID 149)
- Event: WCLC 2019
- Type: Mini Oral Session
- Track: Thymoma/Other Thoracic Malignancies
- Presentations: 1
- Now Available
- Moderators:Kazuya Kondo, Edith Michelle Marom
- Coordinates: 9/10/2019, 11:30 - 13:00, San Francisco (2009)
MA20.07 - Thymomectomy and Total Thymectomy or Simple Thymomectomy for Early Stage Thymoma Without Myasthenia Gravis: An ESTS Thymic Working Group Study (Now Available) (ID 1683)
11:30 - 13:00 | Author(s): Pascal Alexandre Thomas
Resection of thymic tumors has traditionally included removal of the tumor and the thymus gland (thymothymomectomy). Nevertheless, in recent years, some authors questioned the need to remove the thymus gland in non-MG thymomas, suggesting that resection of the tumor (simple-thymomectomy) is enough from an oncological point of view in Stage I (TNM stage classification) thymoma patients. The aim of our study was to compare short- and long-term outcome of thymothymomectomy vs. simple-thymomectomy using European Society of Thoracic Surgeons (ESTS) Thymic Database.Method
We investigated 1131 patients with thymic epithelial tumors included in the ESTS-Thymic Database. Three-hundred twenty-four clinical stage I (cT1N0M0, according to the 8th edition of the UICC/AJCC TNM stage classification) without Myasthenia Gravis (non-MG) thymoma cases were evaluated from 23 contributing centers (2000-2017), of which 300 (93%) thymothymomectomy and 24 (7%) simple-thymomectomy. Surgical upstaging was evaluated. In pathological stage I, we compared the completeness of resection, the rate of complications, the 30-day mortality, the overall survival and the disease-free survival (DFS).Result
Overall, we observed an upstaging to stage III in 10 (3%) patients. We did not observe any significant difference between the two techniques in terms of the completeness of resection, the rate of complications and the 30-day mortality. The 5-year overall survival rate was 94% in the thymothymomectomy group and 56% in the simple-thymomectomy group (Figure 1 - P= 0.0004). The 5-year DFS was 95% in the thymothymomectomy group and 82% in the simple-thymomectomy group (Figure 1 -P= 0.013).
Patients affected by stage I TNM non-MG thymoma submitted to thymothymomectomy presented a significantly better DFS and overall survival than those submitted to simple-thymomectomy. Thymothymomectomy should be considered the procedure of choice in Stage I TNM non-MG thymomas, also considering the not negligible rate of pathological upstaging.
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P2.09 - Pathology (ID 174)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Pathology
- Presentations: 1
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
P2.09-15 - PD-L1 Expression and Lymphocyte Infiltration in Resected Stage IIIAN2 NSCLC: Preliminary Data from a Lung ART Ancillary Study (ID 1344)
10:15 - 18:15 | Author(s): Pascal Alexandre Thomas
Patients with resectable stage IIIA N2 NSCLC, are at high risk of both systemic and loco-regional relapse following surgical resection, necessitating neo-adjuvant or adjuvant treatments. Prognostic biological markers are needed. Parameters from the immune microenvironment, including PD-L1 expression and lymphocytic infiltration, have been poorly described in this group of patients. Thus we assessed simultaneously PD-L1 expression and TIL density in a cohort of stage IIIA N2 Lung ART patients, and correlated the results with clinical and pathological features before adjuvant treatment.Method
Formalin fixed paraffin-embedded tumor surgical specimens from 247 patients included in the Lung Adjuvant Radiotherapy Trial (NCT00410683) were studied. PD-L1 immunohistochemistry was performed centrally on whole slides using a validated clinical PD-L1 assay. Expression of PD-L1 in tumor cells (TC) and immune cell (IC) was scored by a trained pathologist. Morphological assessment of TIL density (percentage of tumor area) was performed on whole hematoxylin-eosin stained slides. Surgical and pathology reports were reviewed by an independent expert committee for tumor staging. Association between immune parameters and baseline clinical characteristics were assessed in exploratory analyses in order to provide insights on immune activity in resected NSCLC patients.Result
PD-L1 expression in ≥1% TC, ≥50% TC, ≥1% IC, ≥10% IC was observed in 47.8%, 21.9%, 61.5%, 7.3% of patients, respectively. In univariate analysis, high PD-L1 expression in both tumor cells and immune cells for all cut points correlated strongly with a higher TIL density (p-values ≤0.001). In 41 (16.6%) patients with preoperative chemotherapy (CT), a higher TIL density was observed (mean 28.1 vs. 17.5%, p=0.0018) as compared to patients without preoperative CT, but no difference was noted for PD-L1 expression in both TC and IC,. Skip N2 metastases were associated with a higher TIL infiltration (mean 22.9% vs. 17.4% p=0.014). We found no significant correlation between PD-L1 or TIL infiltration with the number of mediastinal lymph nodes stations involved on pathological examination and with histological tumor subtypes (squamous cell carcinoma vs. adenocarcinoma).Conclusion
PD-L1 expression levels in TC and IC appeared similar in stage IIIA N2 NSCLC as compared to other stages. Expression in both TC and IC strongly correlated with TIL infiltration, suggesting a prominently immune-induced expression mechanism. Preoperative chemotherapy was associated with a higher TIL infiltration but not higher PD-L1 expression. Patients with skip N2 metastases harbored a higher level of TIL density, a finding consistent with a more active immune microenvironment in this group of patients with better prognosis. These data will be subsequently updated on a larger number of patient and correlated to clinical follow-up.