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O17 - Anatomical Pathology I (ID 128)
- Event: WCLC 2013
- Type: Oral Abstract Session
- Track: Pathology
- Presentations: 1
O17.01 - Prognostic and predictive value of a new IASLC/ATS/ERS lung adenocarcinoma classification in a pooled analysis of four adjuvant chemotherapy trials: a LACE-Bio study (ID 3255)
10:30 - 12:00 | Author(s): E.M. Brambilla
A new IASLC/ATS/ERS classification for lung adenocarcinoma has been proposed to classify invasive lung adenocarcinoma patients according to the predominant growth pattern present in the tumor: lepidic (LEP), papillary (PAP), acinar (ACN), micropapillary (MPP) and solid (SOL). Several studies have reported consistently that early stage resectable lung adenocarcinoma patients with LEP predominant pattern have a better prognosis, while MPP and SOL predominant patterns have a significantly poorer prognosis. However, the prognostic significance of these histological patterns has not been tested in clinical trials. Furthermore, the clinical utility of this new classification for predicting benefit from adjuvant chemotherapy is unknown.
The representative single H&E slide of 1766 non-small cell lung cancer patients from IALT, JBR.10, CALGB 9633 and ANITA adjuvant chemotherapy trials who participated in the LACE-Bio study were reviewed to confirm the histological diagnosis. These cases were independently assessed by two pathologists involved in the development of this new IASLC/ATS/ERS classification for subtyping. Discordant cases were resolved by consensus. Clinical outcomes were overall survival (OS, main outcome), disease-free survival (DFS) and specific disease-free survival (SDFS) (DFS with censoring deaths not related to cancer). Multivariable Cox models stratified by trial were used for prognostic analyses and the interaction between treatment (chemotherapy / control) and histology subtypes added for predictive analyses. The five histology subtypes were first analysed separately and 3 groups (LEP, PAP+ACN and MPP+SOL) were considered.
573 patients were classified as 23 (4%) as LEP, 148 (26%) as ACN, 99 (17%) as PAP, 39 (7%) as MPP and 264 (46%) as SOL. The distribution of histology subtypes was different across trials (p=0.02) but not related with standard prognostic variables. The number of deaths, events and cancer-related events were 269, 320 and 292 respectively. No significant difference was observed between the survival curves of 5 subtypes whatever the endpoint. No prognostic value of 3 histological subtypes was observed for OS (p=0.21 in the control arm) contrary to DFS (p=0.04) and SDFS (p=0.03). These last 2 results were explained by the difference between PAP+ACN and MPP+SOL with hazard ratio (HR)~ACN+PAP vs. MPP+SOL~=0.66 95% confidence interval (CI)=[0.47-0.91] and HR~ACN+PAP vs. MPP+SOL~=0.67 [0.44-0.89] for DFS and SDFS, respectively. Due to the small number of patients with LEP predominant pattern, the predictive value was assessed after excluding this subtype. MPP+SOL patients reported significant DFS benefit from adjuvant chemotherapy (HR=0.58 [0.43-0.80], p<0.001) compared to ACN+PAP patients (HR=1.12 [0.79-1.59], p=0.53; p interaction < 0.01). A similar result was observed for SDFS with HR=0.58 [0.42-0.80], p<0.005 in MPP+SOL compared to HR=1.13 [0.78-1.63], p=0.52 in ACN+PAP (p interaction <0.01) while no predictive effect for OS.
Resectable lung adenocarcinoma patients with micropapillary and solid predominant patterns showed a trend for poorer DFS and SDFS compared to patients with the other subtypes, and they show a significantly higher benefit from adjuvant chemotherapy on these outcomes. Histological subtypes according to the IASLC/ATS/ERS classification may be proposed as a stratification factor in design of future adjuvant chemotherapy trials.
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P3.02 - Poster Session 3 - Novel Cancer Genes and Pathways (ID 149)
- Event: WCLC 2013
- Type: Poster Session
- Track: Biology
- Presentations: 1
- Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P3.02-010 - A PCR-based test detecting ectopic expressions of placenta/germline genes can predict aggressive lung tumours (ID 1648)
09:30 - 16:30 | Author(s): E.M. Brambilla
Cell transformation and tumour progression are associated with severe alterations of the epigenetic control of gene expression. Although the abnormal repression of tumour suppressor genes has been thoroughly investigated, the concept of tissue-specific gene aberrant reactivations in cancer is only starting to emerge. The extent of this process has not been reported yet, mainly because of the difficulties in detecting these expressions by the currently used transcriptomic analyses
We have developed a simple approach, exploiting genome wide expression data, which has enabled us to demonstrate that these "off-context" gene activations occur in any cancer, providing a universal source of cancer biomarkers. By applying this analysis to our series of lung cancer patients (n=297) with the corresponding precise clinical annotations and 5 to 10 years patient follow-up, we found that hundreds of germline-specific genes are ectopically expressed in the tumours and that a subset of 26 genes are specifically activated in a subgroup of highly aggressive metastatic-prone tumours, even at an early stage of the disease. This approach has enabled us to define and isolate a homogeneous group of very aggressive tumours called P3 with at least 3 genes ectopically expressed, independently of other prognosis parameters (histo-pathological or stage) (Rousseaux et al. Sci Transl Med 2013, 5 (186): 186ra66).
Based on these data we setup a PCR based test to directly rank lung tumours by detection of the prognosis associated gene activations. This test was first validated on a series of 60 tumour samples from the same cohort (also analyzed by an affymetrix transcriptomic approach), which revealed the remarkable robustness of the PCR approach and showed a higher sensitivity of the PCR-based detections in tumour ranking. We then extended these PCR-based analyses to include additional patients with precise clinical and pathological annotations and 10 years follow-up but for whom transcriptomic data were not available. Here again we could show that our test successfully ranked the patients into groups with significantly different survival probabilities. we show here the intermediate analysis on a first group of 88 patients without lymph node metastasis treated by surgeryFigure 1
In conclusion we are ready to launch a prospective study based on this PCR test to evaluate its ability to predict tailored follow up of patients after surgery and also tumour sensitivity to design specific targeted therapies including immunotherapy since this ectopic activation may lead to very innovative treatment .