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MO26 - Anatomical Pathology II (ID 129)
- Event: WCLC 2013
- Type: Mini Oral Abstract Session
- Track: Pathology
- Presentations: 1
- Moderators:E. Brambilla, V.L. Capelozzi
- Coordinates: 10/30/2013, 10:30 - 12:00, Bayside 105, Level 1
MO26.14 - Histological Prognostic Markers in Squamous Cell Carcinoma of the Lung (ID 2908)
10:30 - 12:00 | Author(s): A. Drilon
The current IASLC/ERS/ATS classification of pulmonary adenocarcinoma indicates that different patterns of growth in adenocarcinoma are associated with prognostic value. There is however, very little information concerning histological prognostic markers in squamous cell carcinomas of the lung. In contrast to adenocarcinoma, squamous cell carcinoma is more homogeneous histologically. However, the World Health Organization classification of lung tumors recognizes different patterns of growth in squamous cell carcinomas. In this study we evaluated several histological parameters including growth patterns and nuclear features and their association with prognosis in a population of stage 1 squamous cell carcinomas.
A cohort of 165 stage I squamous cell carcinomas of the lung were evaluated. The presence of different histological growth patterns such as papillary, infiltrative, pushing borders, intraalveolar, pseudo-glandular, basaloid, small nest and presence of infiltrating single cells, as well as the cell type (clear cell, transitional, syncytial, and glassy) were evaluated in a semi- quantitative manner by recording the percent of each histological pattern or cell type with 10% increments totaling 100% for tumor. In addition, the presence of peripheral palisading, nuclear features (nuclei size, chromatin patterns, nuclear contour, presence of nucleoli, and mitotic figures), and keratinization were also evaluated. The association of predominant pattern of growth, cell type, and nuclear features with recurrence free survival (RFS), characterized by time to recurrence or death of disease and overall survival (OS) were evaluated.
There were 66 women and 97 men in this population with a mean age of 75±9 year old. All patients were smokers. The mean follow-up was of 47.8 months (4 years). Among histological growth patterns, tumors with predominant papillary and pushing borders appear to have a slightly better outcome compared to other predominant patterns of growth (RFS p=0.05 and OS 0.025). It is interesting to note that squamous cell carcinomas with a predominant basaloid growth pattern, which is considered to be a pattern of poor differentiation, did not have worse prognosis copared to other features. There was no association of cell type, nuclear features, presence of palisading or keratinization with prognosis. There was no difference of nuclear features among tumors with different growth patterns and cell types.
Squamous cell carcinomas appear to be more homogeneous than adenocarcinomas of the lung despite some histological variances. Evaluation of several histological parameters like growth pattern, cell type, and nuclear features failed to indicate a strong association of any of these parameters with prognosis, with exception of papillary and pushing border growth patterns that when present as predominant patterns of growth were associated with a better prognosis. This suggests that contrary to adenocarcinoma, a histological based grading system may not be easily established for squamous cell carcinomas of the lung.
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P2.11 - Poster Session 2 - NSCLC Novel Therapies (ID 209)
- Event: WCLC 2013
- Type: Poster Session
- Track: Medical Oncology
- Presentations: 1
- Coordinates: 10/29/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P2.11-026 - RET Fusion-Positive Advanced Lung Cancers: Response to First-Line Chemotherapy and Survival in Comparison to ROS1 and ALK Fusion-Positive and EGFR- and KRAS-Mutant Lung Cancers (ID 1964)
09:30 - 16:30 | Author(s): A. Drilon
RET fusions are novel targetable drivers in non-small cell lung cancers. While the clinicopathologic profile of patients with RET fusion-positive tumors has been described in early-stage disease, little is known regarding clinical behavior in advanced unresectable disease.
Patients with advanced unresectable (stage IIIB/IV) pan-negative lung adenocarcinomas (absence of mutations in EGFR, KRAS, NRAS, BRAF, MAP2K1, ERBB2, PIK3CA, and AKT, and fusions of ALK or ROS1) were screened for RET fusions via dual-probe break apart FISH testing. Upstream partners were identified via RT-PCR and next-generation sequencing whenever possible. A retrospective review of patient records was conducted to determine response to systemic therapy and overall survival (OS). OS was calculated from diagnosis of metastatic disease and compared to patients with ALK and ROS1 fusion-positive, and EGFR- and KRAS-mutant lung cancers. Survival curves were estimated using the Kaplan-Meier method. Differences in survival between groups were assessed by the log-rank test.
A RET fusion was found in 16% (n=12/76, 95%CI 8%-24%) of pan-negative tumors and 19% (n=10/48, 95%CI 10%-33%) of pan-negative tumors from never-smokers. Patients with RET fusion-positive tumors were predominantly never-smokers (83%, n=10/12, 2 patients with 7 and 10 pack-year histories, respectively) with advanced-stage disease at diagnosis (92%, n=11/12 stage IIIB/IV). Fusion partners were identified in 6 patients (4 KIF5B-RET, 1 TRIM33-RET, 1 NCOA4-RET). Eight patients (67%) received first-line platinum-based therapy, 6 of whom (50%) received maintenance pemetrexed and/or bevacizumab. Partial responses (PRs) were seen in 3 patients (38%) and stable disease (SD) in 5 patients (62%). 1-year OS on chemotherapy and median progression-free survival were 47% and 7.3 months, respectively. 1-year and 2-year OS for patients whose tumors harbored RET, ROS1, or ALK fusions, or EGFR or KRAS mutations is summarized below (Table). OS was not significantly different between RET, ROS1, ALK, or EGFR cohorts when RET was compared to each of the latter three cohorts separately. The presence of a RET fusion was associated with improved OS compared to the presence of a KRAS mutation (HR 0.39, 95%CI 0.21-0.74, p=0.004). Of the 11 patients with RET fusion-positive lung cancers, 4 patients (36%) were treated with cabozantinib on a phase 2 protocol (NCT01639508) with disease shrinkage of -66%, -32%, -23%, and -19% via RECIST v1.1.
Driver Detected OS 1-year [95%CI] OS 2-year [95%CI] RET (n=12) 100% 71% [25%-92%] ROS1 (n=9) 88% [39%-99%] 88% [39%-99%] ALK (n=44) 91% [77%-97%] 73% [55%-85%] EGFR (n=102) 85% [76%-91%] 58% [47%-67%] KRAS (n=117) 60% [50%-66%] 26% [18%-35%]
Response to platinum-based first-line therapy in patients with RET fusion-positive tumors is comparable to historical controls. Survival in patients with RET fusion-positive disease is comparable to patients with EGFR mutations and other recurrent gene fusions (ROS1 and ALK) and improved compared to patients with KRAS mutations. Cabozantinib is worthy of further study in RET fusion-positive lung cancers.